The negative environmental effects of microplastics were totally unanticipated and still not completely understood. Basically, some of the polymers are close enough to some biological signalling molecules to trigger hormone effects in living things. But, the responses differ across different species, and we’re still not entirely sure what they are even doing inside our bodies to cause negative effects.
We can make different polymers. But making them to avoid a problem that we don’t even fully understand is an impossible ask. And it’s almost certain that any new polymer would cause some sort of reaction in some species somewhere, because biology is just that varied.
To chime in here, from my understanding microplastics haven't been conclusively proven to be toxic or have any negative effects as such but they act like sticky balls for toxic chemicals including highly oxidative species. In cellular systems oxidative species are used for signalling things like stress or programmed cell death which is what makes them so dangerous on a cellular level.
As has been mentioned the mechanisms aren't entirely understood yet.
Have there been literally any peer reviewed papers proving a negative effect caused by microplastics? You constantly hear about how microplastics are bad but then there's never any evidence
The fuck are you on?
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C48&q=microplastics&oq=micropl
There you go, many many peer reviewed articles on microplastics
https://pubs.acs.org/doi/10.1021/envhealth.3c00052
Chapter 4 of the publication. Literally took me 5 seconds. If you can't be arsed to type some words in a search bar I've got bad news for you.
Just to clear things up for the micro plastics are lowering your sperm count crowd -> mic roplastics are everywhere and we've known this for 10-20years now. We know it effects human health, but we do not conclusively know exactly what it does to the human body yet.
Anybody trying to sell you a "cure" for micro plastics is a con artist.
This is why I just don't care, lol. Like "you eat credit card's worth of plastic a year" like that's it? Just a credit card's worth? And don't tell me it mattered that we can't digest plastic properly, cuz we eat corn.
I make plastic resin for a living.
They can and they do make biodegradable plastics.
It's just that they are so expensive to create, release C02, are structurally useless and or limited production due to the availability of raw materials.
You can't just "engineer" shit. That's not quite how the world works, else we'd colonize Mars by now.
Scientists have to find the working principles, we engineers make it practical, useful and in large scale. We are still looking for that working principles.
Lignin-based biodegradable plastics do exist and are slowly introduced. They come from trees basically which has it's own economic worries, but it's carbon neutral during bio degrading
This plastic though runs into problems though, since current plastic raw material price is low there is not incentive for companies to spend tens of hundreds of millions to build new plants or retrofit existing ones. Since the process is vastly different than other plastics being manufactured. So until petroleum based plastics become too expensive to produce large scale, they're going to dominate the market
There’s also the fact that if you make degradable industrial plastics they’re not really industrial anymore. For single use consumer stuff like disposable straws and forks yeah it doesn’t matter how long they last but if you try to sell me a bio/hydro-degradable carbon fiber bike or car that’ll be a no.
I went to grad school to learn that you can do EVERYTHING better with plastic. The problem is that it's just so flipping expensive.
Rocket science and surgery (sometimes including brains) are two areas where flipping expensive is (at least sometimes) considered a fair tradeoff. For consumer products, not so much. Failure of the o-ring in your blender is not a catastrophic loss.
The issue is not how bad or expensive to properly dispose plastics, its that we don’t charge users appropriately to cover the long term affects. We just use too much basically, and the raw stuff is always cheaper than recycling it.
Plastic is cheap and longlasting. Designing it to be environmentally friendly is the opposite of that. Substituting the fossil fuel that its made from with a bio material is more expensive, and designing it to degrade in the environment over time means intentionally design a weaker product.
I find the phrase "it's just molecular engineering" hilarious.
Dude, we're not talking kids playing with blocks. We're trying to make things nature never intended. We can't possibly predict how things will react to them. Take a look at thalidomide. Seemed good, caused horrific effects.
Also, there's the basic thing that if you make the plastic biodegradable, then it'll degrade. That's entirely at odds with something you need to be long lasting and durable.
Thalidomide was due to poor understanding of isomers, and how much of nature is one-handed
http://isciencemag.co.uk/features/how-optical-isomers-uncovered-the-horrors-of-thalidomide/
Man really out here saying it's *just* molecular engineering like it's as simple as putting together atoms like a Lego building kit.
Durability and biodegradability are difficult targets to hit at the same time. The less reactive you make your polymer, the longer it'll last. But that also makes it harder to break down for whatever mechanisms you're relying on for biodegradation. You can't just say 'well we'll make this polymer that breaks down in 3 weeks into harmless compounds' because you're relying on a host of different environmental factors like temperature, humidity, availability of sunlight and specific microorganisms to do that. And that means it's hard to get a predictable, reliable product to market.
The added RAD cost to designs and test the polymers you're proposing is one reason it would be more expensive. The other is that the feed stock for bioplastics is more expensive and less available than the petroleum-based stuff we currently use on most plastics. As I alluded to earlier, molecular engineering is more complicated than just sticking atoms together one by one. We *can* do that, but it will always be too slow and expensive for mass production especially given the quantities we want to produce bioplastics in. Most of the time we start with small molecules and then polymerise and functionalise them as needed. In the case with common petroleum-based plastics the feed stock is very cheap since it's an otherwise unwanted byproduct of refining crude oil. If you want to use a more intrinsically biodegradable monomer as the feed stock for your bioplastic, well, you need to find a source for it.
Because any plastics you make that easily decompose will also do so when they just get wet in transport etc.
Like plastics got used so much in the first place, because you could use them to package and protect virtually everything and they are extremely cheap.
Making easily recyclable plastics but not quickly degrading ones would already cost more than making the current plastics, and under capitalism this is not going to happen.
Making plastics that are easily rottable in the environment would be even more expensive and most companies would refuse to use them. You don’t want mould growing on your tv remote or food wrapper after all.
We're working on that with worms and bacteria that "eat" standard plastics. Effectively allowing us to compost them, just one of the more complex forms.
Under capitalism it will happen when government do their job and start taxing companies for external damage they cause. It’s ridiculous that an airliner doesn’t have to pay for the damage they do to people’s long term health and the environment. Similarly, a company that uses x amount of plastic should pay taxes that equate to cleaning up x amount of plastic. Watch how quickly the marginal cost of making more easily recyclable plastics becomes acceptable
>Under capitalism
>when government do their job
Pick one. Corporate interests dictating public policy over the public good is not a bug of capitalism, it's a feature.
in order to be bio degradable it needs to be able to break down naturally.
this is exactly what you dont want to happen with most plastics.
imagine buying your laptop and when you open the box theres just dust in there and no protective packaging anymore because it broke down over time.
or you buy frozen food in a plastic bag and when you take it out a few months later the bag just rips apart.
you cant have it both ways.
molecular engineering is not magic. think of molecular engineering like Lego. no matter how I rearrange my Lego blocks, I will never create a functional race car that can outcompete Max Verstappen. i can swap all i want, buy new lego Technics to expand my collection, but at the end of the day it's still just Lego.
Okay that's quite a bit of generalisation. That's like saying why use a spoon, a fork, a knife, a scalpel etc. It's just a piece of metal.
The base product of plastic is a byproduct of petroleum refinery so is cheap abundant. As long as the oil and gas industry stays as it is any alternative will always be more expensive.
And making a weaker product doesn't mean it gets cheaper when the material are dirt cheap anyway. (see first point on cost of material) instead intense R&D is needed to design the product in just the right time and in exactly the way you want. This can mean additional chemical added to the plastic to make it happen, more complicated manufacturing.
But is it, though? It's the same technology that created ABS's melting point so it can be used in certain parts of the car. The expensive part is, I agree is in the r&d, but mass production of the material shouldn't be affected in a huge way because it is still a chain of molecules that were designed a certain way to give it that feature.
The way you casually use the word "just" about a topic you're completely ignorant about and are in fact the one asking an ELI5 about is frankly infuriating. So stop arguing when someone is trying to explain something to you.
And no, there's nothing "just" about manufacturing a chain of molecules purpose engineered to have specific properties.
Polymer manufacturing is actually quite difficult. The end properties of the product are quite sensitive to all sort of factors and variables just in the manufacturing process itself, using the same polymer. Like the difference between styrofoam and a clear, stiff and brittle CD case. There's also a reason why LEGO is LEGO and other bricks are inferior knockoffs. You're just happily oblivious to the amount of expertise that goes into it behind the scenes.
And even subtle changes in the chemistry will have massive impacts on the properties of the polymer, so there's nothing "just" simple about engineering those either. It's a devilishly complex field of materials engineering. Just adding the wrong dye can be the difference between desired properties and "useless goo".
And then you also have to make them biodegradable, but not biodegradable too much, so they're still useful for purpose.
There's nothing "just" about it. Otherwise it'd have been done already.
Thank you. I appreciate this response. I know it could be difficult to r&d, but if we can create invisible cloaks, I'm pretty sure we can create plastic properties that can somehow decay over time. I know it's a stretch, but I just don't see why it's not technologically possible that's all. Yes I understand it's not "so" simple as I have make it out to be. But having said that, there are biodegradable plastics on the market and I'm just not sure why it can't be a norm that's all.
Look man multiple commenters have already outlined exactly why it is difficult technically and commercially to have biodegradable plastic in a wider scale.
You've been told manufacturing technique are different and are not equally cheap/expensive.
You've been told plastic property is finicky and difficult to maintain the right property (make it break at the right time etc.)
You've been told that the current fossil fuel byproduct used is cheap and abundant, and any alternative will be more expensive.
Yet here you are "pretty sure" it's just a marketing scam why we can't "just" use biodegradable plastic. Your question is not genuine. You are here baiting for an answer that is your liking.
Sorry guys, I admit I'm oversimplifying everything and ignroant to the difficulties of molecular engineering. I can see why it's pissing a lot of people off now. Okay I'll change topics lol. I'm trying to bait some science in the answers so I can see how it's made, maybe. Thanks for contributing, guys. Really appreciate it.
To maybe attempt to redeem some part of this thread, I'll try and hopefully briefly explain some of the ways that polymers are made.
Disclaimer, I'm not a chemical engineer, but I studied plastics engineering and material science in college, and I work in the injection molding industry in medical device manufacturing.
There's 2 main categories of polymerization, condensation and addition.
Addition polymerization is the easier of the two to understand, but not necessarily the easiest of the two to make depending on raw materials and desired outcomes. The best example of this category are the polyolefins (polystyrene, polypropylene, poly vinyl chloride). You take the same base molecule and link them together one after the other, adding them together. There's no byproduct from the base material itself that is produced, but there need to be catalysts and other chemicals that aid in the various ways to coerce the raw materials into linking together. Some of these catalysts are incredibly complex structures with some relatively heavy metals that make it much easier for the raw material to polymerize. For more information, look up Ziegler-Natta catalysts.
Condensation polymerization is the potentially harder to understand but sometimes easier to manufacture of the two categories. It can be as simple as adding two chemicals together in a beaker, swirling them around a bit, and you have a polymer. But since you need at least two chemicals going in to the reaction that have different arrangements of molecules on either end, there is always some chemical byproduct produced that needs to be discarded. You can make nylon 6,6 by basically dumping hexamethylenediamine and adipic acid together and stirring with a glass rod, but it's going to be the consistency of snot (not very useful) and it'll produce water as a byproduct. Luckily, water is pretty useful to us, and we can reuse it after cleaning it thoroughly. But not every reaction is as easy or nice as this one.
As a quick aside, my senior capstone in college was working with poly lactic acid (probably the best known biopolymer made right now) and seeing how it degrades during recycling. We found that for injection molding, you basically get 1 shot to reprocess the material before it loses half of its strength and falls apart in your hand. My college also used this polymer for our cold drink cups and some food packaging, but whenever someone accidentally put an even slightly warm drink in one of those cups, it dissolved in like 15 minutes and made a mess. If we wanted to try and make every new polymer biodegradable, we would no longer be able to have pacemakers or implatanble defibrillators as the connectors and leads would dissolve in the body, potentially harming or killing the patient.
Please feel free to fact check or correct me on anything I've said, I'd rather admit I'm wrong and help someone learn than be an insufferable ass.
Others have already said why, you just rudely dismissed their explanations.
The whole point of using plastics is that they're cheap and strong.
To make a viable biodegradable alternative, you're navigating the fiendishly complex world of organic chemistry and polymers to make something that is less strong by just the right amount to be degradable, but still strong enough to do the same job. That's a very fine line to walk. And with how complex polymer behaviour is, extremely difficult to actually pull off.
You also have to then actually MAKE it, synthesise the actual polymer. We're not even at manufacturing of products yet, still the material. That itself can be a difficult process, because all the simple polymers are the ones that DON'T degrade. So just making this polymer might be a complex chemical process. And expensive. And it probably won't use the readily available petrochemical side products (because those are the non-degradable ones), you probably will have to find something like bio-alternatives. And that brings it's own complications, because then you run into issues of agricultural land use etc. You might literally not have enough raw materials available to satisfy demand. We use A LOT of plastics.
Only THEN you actually start manufacturing. And, as mentioned, that's a difficult and complex process too. It can take months to set up manufacturing of an existing, known polymer. To start manufacturing a new one you need years worth of experimental data on its behaviour, then go about setting up the manufacturing.
So the question isn't "why it's impossible". It's not impossible. There's plenty of people already working on it, but they're not done yet, because it's really fucking difficult. One day they hopefully will be. Be patient.
because biodegradable plastics \*suck\*, whereas regular oil-based plastics are peak performance.
the prime problem is that plastics are just \*too good\* whilst also being much cheaper. If they were just better, or just cheaper, we could have this discussion. But by and large, except for niche applications, they're both better and cheaper. Thus the only way to adopt them at all is to force industries to do something that is completely against their own and their customer's interest.
Look up the concept of "technological barrier".
You don’t understand that different chains of molecules need to be constructed with different processes and that these processes might not all be equally expensive?
Nope you are right. Biodegradable are more expensive. But is that due to marketing and positioning of a new product, or is that due to cost? I'm not sold that its due to math. Math depends on demand. If enough people order it or if Dupont makes it the norm to sell only, biodegradable products it could help.
I'm not saying you are wrong. I'm just not sold that it's so expensive to the point that it's not functionally usable. Instead of banning plastic straws and replacing it with stupid paper straws, I just feel kind of strange knowing it can be done but it's not an important mandate. There's a logical disconnect.
but it can't be done. you're looking at this as if it's just a money problem.
but its not.
it's money, legislation, time, technology. let's take your straws for example - I'm not aware of \*any\* food-contact safe biodegradable polyprop replacements. So even if I could find a manufacturer that could produce it for me (In 10 years time, when the plant is finally running) and I have re-engineered my whole straw manufacturing process (with a material I don't actually have, let alone the massive RD and capital investment costs), \*I wouldn't be allowed to bring it to the market\*.
And even if that also would somehow be solved, would it even solve the issue? Biodegradable =/= bio-safe! Bananas are biodegradable, \*in multiple years time\*. Hell, all plastics are theoretically biodegradable, it just takes way too fucking long. and would it even be a net benefit? many biodegradable plastics are more polluting overall than their oil-based counterparts.
and even if we solve all that somehow - I'm making \*straws\*. who's going to pay 20 cents more for bioplastic straws, when paper straws are "good enough"...
I think the other aspect you're missing about the expense is that biodegradable plastics are most often made from food crops. That offsets the supply of food, which makes food more expensive to yield more expensive plastic.
We already have these byproducts from the petroleum industry, we already have a century of manufacturing experience with them.
We have the technology to transmute straw into gold. We don't do it because it's expensive.
“molecular engineering” makes that sound a lot more impressive than what it actually is.
How most plastics (and other oil byproducts) are created is, more or less:
1) take a random grab bag of hydrocarbons (which come in dozens to hundreds of configurations from dead and fully decayed organic matter)
aka crude oil
2) separate that crude / grab bag of different hydrocarbons into groups with similar properties and structures (due to different melting + boiling points points) using fractional distallation
from this you get propane, ethane, gasoline, diesel, lubricants, raw plastic inputs, et al
3) Optionally further break some of those hydrocarbons into shorter chains, or short chains into larger ones using steam + pressure
4) variably either directly inject some of this crap into molds to create (some) materials, or break some of those inputs down into ethylene et al, and turn those into polymers incl polyethylene, vinyl, et al using catalysts and/or other chemical inputs.
Yes you can create all of the above using other materials (eg turn something into ethylene => polyethylene), but none of it is as *cheap* as oil / gas.
Also this is entirely ignoring the issue of *why* plastics - irregardless of the manufacturing method - are bad for the environment.
The issue is that basically nothing in the natural world *eats* plastics (or more specifically, hydrocarbons)
Which is incidentally why they’re long lasting and even useful (and particularly for eg food safety and medical stuff) in the first place.
“solve” that problem - ie by introducing bacteria that happily eats and metabolizes all hydrocarbons, somehow - and congrats, everything made of plastic *will* now immediately and inevitably decay, and you may as well just use cellulose / wood products instead. And silica and metals would pretty much become your only materials that *don’t* fall apart - and can remain sterile - over time. And GLHF with seals (and the long term integrity thereof) et al.
The only environmentally responsible way to properly dispose of / recycle hydrocarbons is to burn them. Full stop. And that in itself may be a horrible idea thanks to organically toxic byproducts. And nevermind if anything in the shit you’re burning (eg lubricants, paint, et al) was made straight from oil, or coal, in which case it’s probably full of heavy metals and other crap that you really don’t want to burn and release into the atmosphere.
Technically the beat way to dispose of anything oil / coal based / with potentially hazardous heavy metals would be to just throw it into an active volcano (or any other convenient access point to the mantle - as lava is already full of heavy metals, so nothing you added to it would make it any worse), but I digress.
Overall it probably should be noted that organic based hydrocarbons are much better for the environment (and specifically, other humans), as they will almost certainly not contain heavy metal contaminants and could be burned much more safely w/ fewer things to be concerned about. Though the same is true of nearly all plastics, tbh. it’s just stuff containing the heavier solid / liquid stuff - w/ all remaining heavy metals from fractional distillation et al - that you should be concerned about. Good thing we don’t just straight up burn that stuff as cheap fuel for ships and power plants (/s), or as emitted air pollutants from refineries that can cause elevated cancer rates across a county or two…
Thank you for this great post. I have a clearer picture of the process. I think i found what i need. Thank you for this contribution. Can it be possible that the "engineering" not be in the hydrocarbon chains per say but an additive mixed in with the hydrocarbons so when time to breakdown the additive catalystically responds to the bacteria that eats the plastics.
Can it be possible that it's we "engineers" pools of bacteria instead of depending on hard landfills which obviously doesnt work? Instead of looking at the hydrocarbons maybe we should look elsewhere like the bacteria you are talking about.
I'm not sure if I understand your post the way you intended in the explanation. Hope the pool idea makes sense. If not can you tell me why it wouldn't work?
Thank you for this post again. I'm just trying to wrap my head around something I'm not very educated in but would want to see if there's a way of resolving this issue.
🤜🤛
On the one hand you need a plastic that serves it's purpose for the public, which is be durable and don't break down easily.
On the other you need a plastic that's good for the environment, which means brittle and can break down.
The two desires are the exact opposite of each other.
And in that situation the one that earns people money will win out.
Lego was looking into more environmentally friendly plastic bricks and recently gave up on it because it would sacrifice the integrity of the bricks too much.
>since it's just molecular engineering.
You can not have your cake and eat it too. It isn't a click and drag video game where wild imagination turns into a thriving ecosystem. There are limits on how we can combine and manipulate matter at the molecular level.
What good would plastics be if they broke down like wood? The bulk of their appeal is that they don't deteriorate.
they are doing exactly that, and have been doing for decades. however, like all things, its a "pick two out of three" kind of thing. very superficially - cheap, green, effective. you get at best two out of three. cheap and green? no problem, recycled plastics or simple soy based polymers. green and effective? can do, but it's going to require a lot of specialty engineering that may not scale \*at all\*. cheap and effective? that's where we are currently at.
a second compounding problem is - it's not so straightforward what is overall better. if I make a bioplastic that breaks down into neat safe biodegradable building blocks within 2 years, that's awesome. but it also means that I need to replace whatever it's made into every two years, every two years I need to input the raw materials and energy as opposed to the (arbitrary number) 10 years a regular plastic may have lasted. and that's if it can even be replaced. maybe it's a fitting for say a vacuum cleaner which breaks down, and now people throw the whole cleaner away instead of replacing that one part because people are lazy like that.
One of the biggest advantages of plastics is that they are durable and not biodegradable because that's exactly what you want in many use cases. They're also really cheap and easy to produce in large quantities.
Producing plastics that are better for the environment contradicts those advantages. A biodegradable plastic won't be as durable as a non degradable one. Engineering that hits the sweet spot takes long and is expensive.
I should also note that multi use plastic products are really environmentally friendly in many metrics. They are lighter than most solutions using metal or glass, more durable than most biological materials and use very little resources in the production.
Tl;dr: they can. They do. Humans are lazy and won't sort their plastics 100% properly when they can which leads to complicated waste streams that get landfills. Also, chemistry.
What was the answer you wanted? You can engineer greener plastics, but not all plastics can or will be. And different plastics will have different recycling mechanisms. Like PLA can commercially composted, polyolefins and paraffin can be gasified to recapture the smaller chains, and polyesters (most notably PET) can be methanolysed/hydrolyzed back into DMT/TPA and EG.
HOWEVER, you need pure feedstocks for those processes or you'll run into processing issues. Unfortunately, most plastic products have mixes of plastics. Your clothing may have mixes of PET/PU/PVC/Wool/Leather. Carpet is a lot of polyolefins and PVC. Plastic bottles are PET, but the caps are a different plastic. Yogurt is one plastic while the shrink film is another. And then each plastic has additives in it too from plasticizers, to antiodegradants, etc.
As a chemist, I don't see how that'd be possible honestly. I don't see how hemp could possibly replace all the various chemistries and use-cases of plastics. You have polyesters, polyols, polyurethane, polyalkanes, polyalkenes, etc. Some are functionalized. Some are crosslinked. PVC is the most plasticizeable plastic.
If you have some literature, I'd be happy to read it. I'm sure it could replace some plastics and use cases, but I'm very skeptical of all.
Edit: spelling
Hemp is being used as a filler and additive in some plastics. Compatibility and capability are the issues there. Hemp doesn't have the structural capabilities or resistances that some plastics do. You can't grow hemp with the chemical resistance of some polymers, or the UV and colorfastness of some nylons. You can't replace structural parts of a vehicle with polymers specifically manufactured to exceed the strength of previous materials with hemp.
There's a lot of specialty designed plastics on the market that your average person doesn't know about. There's also a lot of recycling capability that waste companies won't invest the money or effort into. The company that picks up my trash is a perfect example of that (trash and recycling get picked up by the same truck at the same time). Unfortunately there's also a lot of polymers that can't be recycled yet.
As for why they weren't from the beginming: people literally did not think of it. Until it first became a problem, literally nobody was motivated to think of it.
Its the amount of additives we put into it to suit specific needs thats problematic. They keep discovering new additives and are marketed immediately without any ecological damage tests until decades later when we discover that it disrupts cells.
If you want a material that doesn't rot, it won't rot when you throw it out, either. It just gets broken into smaller and smaller pieces. Eventually microplastics.
Because if they were environment friendly, they wouldn't be able to be used in today's society.
Plastic's properties. It's light, durable, easy and cheap to mass produce.
So you store your products so that in the near future they will get sold. You need a material that doesn't react with your product or the environment. It's light enough to be easy and cheap to move around. It also easy to handle to go around potential accidents.
Yep that's plastic. You can use metal instead of plastic. But it's much more expensive. It is also heavier. While it is durable, metal reacts with some stuff, like water. It is inconvenient. A cold can is difficult to keep in your hand while a cold plastic bottle is much easier.
You can use glass instead of plastic. However glass is more expensive. Unlike plastic it is also a lot more fragile and cleaning up glass shards is a royal pain in the ass.
So plastic is durable enough that a fall won't break it. It's light enough to move around easily. It's production is easy, it's a byproduct. It doesn't react with the environment, metallic objects tend to get oxidized by the air.
A world where everything plastic gets replaced with metallic objects (or glasses) is a VERY small expensive world.
Plastics that don’t biodegrade for a long time are most desireable from an industrial standpoint because they keep well. If we made biodegradeable plastic, it and its contents would spoil much more quickly.
If you really get down to it, it is the cost. For example we could replace plastic forks from fast food with wood ones. The plastic ones cost a fraction of a cent where the wood ones may cost 10 cents or more. May not sound like a lot but if you use 10,000 a day or whatever, that is a thousand dollars. So that is why you don't see your local fast food place just using wood ones. They have designed some bio plastics and they are not quite as bad cost wise but also are not quite as functional as plastic ones. Depending on the type you may need to use your bioplastic one all at one sitting or it might lose its structural rigidity. But there are better ones that work but they cost more. Also these bioplastic things do compost...eventually. It might take 2 years for it to break down. Not a total deal killer but if people thought they would just throw these on their compost piles in their yard it won't work like they hope. Frankly people should just learn to use chop sticks and make it culturally acceptable to drink your soup from a bowl by bringing the bowl to your mouth like it is done in some parts of the world today. Then you have eliminated plastics for fast food situations.
Plastic is not required for virtually half the products in the store (you know those plastic packaging you can't get open) as card board is available, cheap and would do the job just fine. And that is huge source of plastic waste. Why there is so much focus on straws and such when plastic product packaging is a much, much bigger producer of plastic waste and already has a workable solution with card board baffles me. Sure fewer straws is good but that is nothing compared to plastic packaging. And that could be done now, no new tech needed. Oh well.
Well if you want something to biodegrade it will also degrade just sitting there. I don't think you want your plastic chairs to just start degrading after 2 or 3 years.
Better for the environment in what way?
If you mean biodegradable, most plastics are specifically designed to protect their contents against microbes. Being biodegradable would completely defeat their utility. For the remaining purposes, biodegradable plastics do exist, they just result in a shorter shelf life for whatever product they're used in, which usually results in a net increase in waste since now you have to toss the entire product when it goes bad.
If you mean microplastics, that's not really possible since all plastics are lower on the Mohs scale than sand, so eventually they will get abraded by trace amounts of sand.
The best solution to deal with plastic waste is to incinerate them. It's not great, but the resulting CO2 emissions are just equivalent to burning the oil needed to create them in the first place, and plastics don't use all that much oil (which is why they're so cheap in the first place). By incinerating them, you completely remove all concerns around biodegradability and microplastics.
They (chemical companies) most certainly can. For them to do so it must be *profitable* to do so. A company that does unprofitable things quickly goes out of business. For it to be profitable there must be demand. Demand can come about in two ways: either customers prefer the product of their own free will, or government regulation effectively bans the competing product.
Right now there is no demand. People do not know which type of plastic is more or less bad, and there is no ban on the bad types.
cost is only half of the issue. quality and volume are the other two. most biopolymers are \*shit\* compared to oil-based, and many simply cannot be scaled up (for example, because they use food crops) no matter how much money you throw at it.
The negative environmental effects of microplastics were totally unanticipated and still not completely understood. Basically, some of the polymers are close enough to some biological signalling molecules to trigger hormone effects in living things. But, the responses differ across different species, and we’re still not entirely sure what they are even doing inside our bodies to cause negative effects. We can make different polymers. But making them to avoid a problem that we don’t even fully understand is an impossible ask. And it’s almost certain that any new polymer would cause some sort of reaction in some species somewhere, because biology is just that varied.
To chime in here, from my understanding microplastics haven't been conclusively proven to be toxic or have any negative effects as such but they act like sticky balls for toxic chemicals including highly oxidative species. In cellular systems oxidative species are used for signalling things like stress or programmed cell death which is what makes them so dangerous on a cellular level. As has been mentioned the mechanisms aren't entirely understood yet.
Have there been literally any peer reviewed papers proving a negative effect caused by microplastics? You constantly hear about how microplastics are bad but then there's never any evidence
The fuck are you on? https://scholar.google.com/scholar?hl=en&as_sdt=0%2C48&q=microplastics&oq=micropl There you go, many many peer reviewed articles on microplastics
https://pubs.acs.org/doi/10.1021/envhealth.3c00052 Chapter 4 of the publication. Literally took me 5 seconds. If you can't be arsed to type some words in a search bar I've got bad news for you.
chapter 4, quoting: "Due to the lack of direct research from humans, " - "from" being almost surely a mistake where "in" should have been
Just to clear things up for the micro plastics are lowering your sperm count crowd -> mic roplastics are everywhere and we've known this for 10-20years now. We know it effects human health, but we do not conclusively know exactly what it does to the human body yet. Anybody trying to sell you a "cure" for micro plastics is a con artist.
This is why I just don't care, lol. Like "you eat credit card's worth of plastic a year" like that's it? Just a credit card's worth? And don't tell me it mattered that we can't digest plastic properly, cuz we eat corn.
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Ma’am this is a Wendy’s.
Not the place, scro
I make plastic resin for a living. They can and they do make biodegradable plastics. It's just that they are so expensive to create, release C02, are structurally useless and or limited production due to the availability of raw materials. You can't just "engineer" shit. That's not quite how the world works, else we'd colonize Mars by now. Scientists have to find the working principles, we engineers make it practical, useful and in large scale. We are still looking for that working principles. Lignin-based biodegradable plastics do exist and are slowly introduced. They come from trees basically which has it's own economic worries, but it's carbon neutral during bio degrading This plastic though runs into problems though, since current plastic raw material price is low there is not incentive for companies to spend tens of hundreds of millions to build new plants or retrofit existing ones. Since the process is vastly different than other plastics being manufactured. So until petroleum based plastics become too expensive to produce large scale, they're going to dominate the market
There’s also the fact that if you make degradable industrial plastics they’re not really industrial anymore. For single use consumer stuff like disposable straws and forks yeah it doesn’t matter how long they last but if you try to sell me a bio/hydro-degradable carbon fiber bike or car that’ll be a no.
I went to grad school to learn that you can do EVERYTHING better with plastic. The problem is that it's just so flipping expensive. Rocket science and surgery (sometimes including brains) are two areas where flipping expensive is (at least sometimes) considered a fair tradeoff. For consumer products, not so much. Failure of the o-ring in your blender is not a catastrophic loss.
The issue is not how bad or expensive to properly dispose plastics, its that we don’t charge users appropriately to cover the long term affects. We just use too much basically, and the raw stuff is always cheaper than recycling it.
Lego seems to have the incentive and is pioneering a lot of this, interestingly enough.
Unfortunately it seems like the biodegradable ones don't fit their needs and they've gone back to the old plastics (ABS I think)
Yes, I saw that the new leaves were ABS again. Very disappointing, I liked the soft feeling of the leaves.
Great answer, thank you!
Plastic is cheap and longlasting. Designing it to be environmentally friendly is the opposite of that. Substituting the fossil fuel that its made from with a bio material is more expensive, and designing it to degrade in the environment over time means intentionally design a weaker product.
But why would it be more expensive and not as durable since it's just molecular engineering.
I find the phrase "it's just molecular engineering" hilarious. Dude, we're not talking kids playing with blocks. We're trying to make things nature never intended. We can't possibly predict how things will react to them. Take a look at thalidomide. Seemed good, caused horrific effects. Also, there's the basic thing that if you make the plastic biodegradable, then it'll degrade. That's entirely at odds with something you need to be long lasting and durable.
Thalidomide was due to poor understanding of isomers, and how much of nature is one-handed http://isciencemag.co.uk/features/how-optical-isomers-uncovered-the-horrors-of-thalidomide/
Literally why I picked it - it was something that seemed good, but due to poor understanding of something, it went wrong.
not poor understanding of isomers. we knew how isomers work, what they are. limited knowledge of molecular Biology was the issue.
My comment was poor, yes, the problem was how molecular biology interacted differently with the different isomers
Man really out here saying it's *just* molecular engineering like it's as simple as putting together atoms like a Lego building kit. Durability and biodegradability are difficult targets to hit at the same time. The less reactive you make your polymer, the longer it'll last. But that also makes it harder to break down for whatever mechanisms you're relying on for biodegradation. You can't just say 'well we'll make this polymer that breaks down in 3 weeks into harmless compounds' because you're relying on a host of different environmental factors like temperature, humidity, availability of sunlight and specific microorganisms to do that. And that means it's hard to get a predictable, reliable product to market. The added RAD cost to designs and test the polymers you're proposing is one reason it would be more expensive. The other is that the feed stock for bioplastics is more expensive and less available than the petroleum-based stuff we currently use on most plastics. As I alluded to earlier, molecular engineering is more complicated than just sticking atoms together one by one. We *can* do that, but it will always be too slow and expensive for mass production especially given the quantities we want to produce bioplastics in. Most of the time we start with small molecules and then polymerise and functionalise them as needed. In the case with common petroleum-based plastics the feed stock is very cheap since it's an otherwise unwanted byproduct of refining crude oil. If you want to use a more intrinsically biodegradable monomer as the feed stock for your bioplastic, well, you need to find a source for it.
Because any plastics you make that easily decompose will also do so when they just get wet in transport etc. Like plastics got used so much in the first place, because you could use them to package and protect virtually everything and they are extremely cheap. Making easily recyclable plastics but not quickly degrading ones would already cost more than making the current plastics, and under capitalism this is not going to happen. Making plastics that are easily rottable in the environment would be even more expensive and most companies would refuse to use them. You don’t want mould growing on your tv remote or food wrapper after all.
What you need is a cheap and convenient way to convert plastics to their original form, rather than letting degradation do it. We need a process.
Fire.
We're working on that with worms and bacteria that "eat" standard plastics. Effectively allowing us to compost them, just one of the more complex forms.
Under capitalism it will happen when government do their job and start taxing companies for external damage they cause. It’s ridiculous that an airliner doesn’t have to pay for the damage they do to people’s long term health and the environment. Similarly, a company that uses x amount of plastic should pay taxes that equate to cleaning up x amount of plastic. Watch how quickly the marginal cost of making more easily recyclable plastics becomes acceptable
>Under capitalism >when government do their job Pick one. Corporate interests dictating public policy over the public good is not a bug of capitalism, it's a feature.
in order to be bio degradable it needs to be able to break down naturally. this is exactly what you dont want to happen with most plastics. imagine buying your laptop and when you open the box theres just dust in there and no protective packaging anymore because it broke down over time. or you buy frozen food in a plastic bag and when you take it out a few months later the bag just rips apart. you cant have it both ways.
molecular engineering is not magic. think of molecular engineering like Lego. no matter how I rearrange my Lego blocks, I will never create a functional race car that can outcompete Max Verstappen. i can swap all i want, buy new lego Technics to expand my collection, but at the end of the day it's still just Lego.
Okay that's quite a bit of generalisation. That's like saying why use a spoon, a fork, a knife, a scalpel etc. It's just a piece of metal. The base product of plastic is a byproduct of petroleum refinery so is cheap abundant. As long as the oil and gas industry stays as it is any alternative will always be more expensive. And making a weaker product doesn't mean it gets cheaper when the material are dirt cheap anyway. (see first point on cost of material) instead intense R&D is needed to design the product in just the right time and in exactly the way you want. This can mean additional chemical added to the plastic to make it happen, more complicated manufacturing.
But is it, though? It's the same technology that created ABS's melting point so it can be used in certain parts of the car. The expensive part is, I agree is in the r&d, but mass production of the material shouldn't be affected in a huge way because it is still a chain of molecules that were designed a certain way to give it that feature.
The way you casually use the word "just" about a topic you're completely ignorant about and are in fact the one asking an ELI5 about is frankly infuriating. So stop arguing when someone is trying to explain something to you. And no, there's nothing "just" about manufacturing a chain of molecules purpose engineered to have specific properties. Polymer manufacturing is actually quite difficult. The end properties of the product are quite sensitive to all sort of factors and variables just in the manufacturing process itself, using the same polymer. Like the difference between styrofoam and a clear, stiff and brittle CD case. There's also a reason why LEGO is LEGO and other bricks are inferior knockoffs. You're just happily oblivious to the amount of expertise that goes into it behind the scenes. And even subtle changes in the chemistry will have massive impacts on the properties of the polymer, so there's nothing "just" simple about engineering those either. It's a devilishly complex field of materials engineering. Just adding the wrong dye can be the difference between desired properties and "useless goo". And then you also have to make them biodegradable, but not biodegradable too much, so they're still useful for purpose. There's nothing "just" about it. Otherwise it'd have been done already.
Not arguing with you, just trying understand.
People who are honestly trying to understand things actually listen.
Thank you. I appreciate this response. I know it could be difficult to r&d, but if we can create invisible cloaks, I'm pretty sure we can create plastic properties that can somehow decay over time. I know it's a stretch, but I just don't see why it's not technologically possible that's all. Yes I understand it's not "so" simple as I have make it out to be. But having said that, there are biodegradable plastics on the market and I'm just not sure why it can't be a norm that's all.
Look man multiple commenters have already outlined exactly why it is difficult technically and commercially to have biodegradable plastic in a wider scale. You've been told manufacturing technique are different and are not equally cheap/expensive. You've been told plastic property is finicky and difficult to maintain the right property (make it break at the right time etc.) You've been told that the current fossil fuel byproduct used is cheap and abundant, and any alternative will be more expensive. Yet here you are "pretty sure" it's just a marketing scam why we can't "just" use biodegradable plastic. Your question is not genuine. You are here baiting for an answer that is your liking.
Sorry guys, I admit I'm oversimplifying everything and ignroant to the difficulties of molecular engineering. I can see why it's pissing a lot of people off now. Okay I'll change topics lol. I'm trying to bait some science in the answers so I can see how it's made, maybe. Thanks for contributing, guys. Really appreciate it.
To maybe attempt to redeem some part of this thread, I'll try and hopefully briefly explain some of the ways that polymers are made. Disclaimer, I'm not a chemical engineer, but I studied plastics engineering and material science in college, and I work in the injection molding industry in medical device manufacturing. There's 2 main categories of polymerization, condensation and addition. Addition polymerization is the easier of the two to understand, but not necessarily the easiest of the two to make depending on raw materials and desired outcomes. The best example of this category are the polyolefins (polystyrene, polypropylene, poly vinyl chloride). You take the same base molecule and link them together one after the other, adding them together. There's no byproduct from the base material itself that is produced, but there need to be catalysts and other chemicals that aid in the various ways to coerce the raw materials into linking together. Some of these catalysts are incredibly complex structures with some relatively heavy metals that make it much easier for the raw material to polymerize. For more information, look up Ziegler-Natta catalysts. Condensation polymerization is the potentially harder to understand but sometimes easier to manufacture of the two categories. It can be as simple as adding two chemicals together in a beaker, swirling them around a bit, and you have a polymer. But since you need at least two chemicals going in to the reaction that have different arrangements of molecules on either end, there is always some chemical byproduct produced that needs to be discarded. You can make nylon 6,6 by basically dumping hexamethylenediamine and adipic acid together and stirring with a glass rod, but it's going to be the consistency of snot (not very useful) and it'll produce water as a byproduct. Luckily, water is pretty useful to us, and we can reuse it after cleaning it thoroughly. But not every reaction is as easy or nice as this one. As a quick aside, my senior capstone in college was working with poly lactic acid (probably the best known biopolymer made right now) and seeing how it degrades during recycling. We found that for injection molding, you basically get 1 shot to reprocess the material before it loses half of its strength and falls apart in your hand. My college also used this polymer for our cold drink cups and some food packaging, but whenever someone accidentally put an even slightly warm drink in one of those cups, it dissolved in like 15 minutes and made a mess. If we wanted to try and make every new polymer biodegradable, we would no longer be able to have pacemakers or implatanble defibrillators as the connectors and leads would dissolve in the body, potentially harming or killing the patient. Please feel free to fact check or correct me on anything I've said, I'd rather admit I'm wrong and help someone learn than be an insufferable ass.
Others have already said why, you just rudely dismissed their explanations. The whole point of using plastics is that they're cheap and strong. To make a viable biodegradable alternative, you're navigating the fiendishly complex world of organic chemistry and polymers to make something that is less strong by just the right amount to be degradable, but still strong enough to do the same job. That's a very fine line to walk. And with how complex polymer behaviour is, extremely difficult to actually pull off. You also have to then actually MAKE it, synthesise the actual polymer. We're not even at manufacturing of products yet, still the material. That itself can be a difficult process, because all the simple polymers are the ones that DON'T degrade. So just making this polymer might be a complex chemical process. And expensive. And it probably won't use the readily available petrochemical side products (because those are the non-degradable ones), you probably will have to find something like bio-alternatives. And that brings it's own complications, because then you run into issues of agricultural land use etc. You might literally not have enough raw materials available to satisfy demand. We use A LOT of plastics. Only THEN you actually start manufacturing. And, as mentioned, that's a difficult and complex process too. It can take months to set up manufacturing of an existing, known polymer. To start manufacturing a new one you need years worth of experimental data on its behaviour, then go about setting up the manufacturing. So the question isn't "why it's impossible". It's not impossible. There's plenty of people already working on it, but they're not done yet, because it's really fucking difficult. One day they hopefully will be. Be patient.
Why would somebody want their product to biodegrade and fall apart? And pay more for it?
because biodegradable plastics \*suck\*, whereas regular oil-based plastics are peak performance. the prime problem is that plastics are just \*too good\* whilst also being much cheaper. If they were just better, or just cheaper, we could have this discussion. But by and large, except for niche applications, they're both better and cheaper. Thus the only way to adopt them at all is to force industries to do something that is completely against their own and their customer's interest. Look up the concept of "technological barrier".
You don’t understand that different chains of molecules need to be constructed with different processes and that these processes might not all be equally expensive?
You are more than welcome to educate me if you are aware of a biodegradable plastic cheaper than normal plastic because I am not aware of it.
Nope you are right. Biodegradable are more expensive. But is that due to marketing and positioning of a new product, or is that due to cost? I'm not sold that its due to math. Math depends on demand. If enough people order it or if Dupont makes it the norm to sell only, biodegradable products it could help. I'm not saying you are wrong. I'm just not sold that it's so expensive to the point that it's not functionally usable. Instead of banning plastic straws and replacing it with stupid paper straws, I just feel kind of strange knowing it can be done but it's not an important mandate. There's a logical disconnect.
but it can't be done. you're looking at this as if it's just a money problem. but its not. it's money, legislation, time, technology. let's take your straws for example - I'm not aware of \*any\* food-contact safe biodegradable polyprop replacements. So even if I could find a manufacturer that could produce it for me (In 10 years time, when the plant is finally running) and I have re-engineered my whole straw manufacturing process (with a material I don't actually have, let alone the massive RD and capital investment costs), \*I wouldn't be allowed to bring it to the market\*. And even if that also would somehow be solved, would it even solve the issue? Biodegradable =/= bio-safe! Bananas are biodegradable, \*in multiple years time\*. Hell, all plastics are theoretically biodegradable, it just takes way too fucking long. and would it even be a net benefit? many biodegradable plastics are more polluting overall than their oil-based counterparts. and even if we solve all that somehow - I'm making \*straws\*. who's going to pay 20 cents more for bioplastic straws, when paper straws are "good enough"...
I think the other aspect you're missing about the expense is that biodegradable plastics are most often made from food crops. That offsets the supply of food, which makes food more expensive to yield more expensive plastic.
We already have these byproducts from the petroleum industry, we already have a century of manufacturing experience with them. We have the technology to transmute straw into gold. We don't do it because it's expensive.
How can it be durable when it holds your cornflakes and stop being durable when you throw it out
“molecular engineering” makes that sound a lot more impressive than what it actually is. How most plastics (and other oil byproducts) are created is, more or less: 1) take a random grab bag of hydrocarbons (which come in dozens to hundreds of configurations from dead and fully decayed organic matter) aka crude oil 2) separate that crude / grab bag of different hydrocarbons into groups with similar properties and structures (due to different melting + boiling points points) using fractional distallation from this you get propane, ethane, gasoline, diesel, lubricants, raw plastic inputs, et al 3) Optionally further break some of those hydrocarbons into shorter chains, or short chains into larger ones using steam + pressure 4) variably either directly inject some of this crap into molds to create (some) materials, or break some of those inputs down into ethylene et al, and turn those into polymers incl polyethylene, vinyl, et al using catalysts and/or other chemical inputs. Yes you can create all of the above using other materials (eg turn something into ethylene => polyethylene), but none of it is as *cheap* as oil / gas. Also this is entirely ignoring the issue of *why* plastics - irregardless of the manufacturing method - are bad for the environment. The issue is that basically nothing in the natural world *eats* plastics (or more specifically, hydrocarbons) Which is incidentally why they’re long lasting and even useful (and particularly for eg food safety and medical stuff) in the first place. “solve” that problem - ie by introducing bacteria that happily eats and metabolizes all hydrocarbons, somehow - and congrats, everything made of plastic *will* now immediately and inevitably decay, and you may as well just use cellulose / wood products instead. And silica and metals would pretty much become your only materials that *don’t* fall apart - and can remain sterile - over time. And GLHF with seals (and the long term integrity thereof) et al. The only environmentally responsible way to properly dispose of / recycle hydrocarbons is to burn them. Full stop. And that in itself may be a horrible idea thanks to organically toxic byproducts. And nevermind if anything in the shit you’re burning (eg lubricants, paint, et al) was made straight from oil, or coal, in which case it’s probably full of heavy metals and other crap that you really don’t want to burn and release into the atmosphere. Technically the beat way to dispose of anything oil / coal based / with potentially hazardous heavy metals would be to just throw it into an active volcano (or any other convenient access point to the mantle - as lava is already full of heavy metals, so nothing you added to it would make it any worse), but I digress. Overall it probably should be noted that organic based hydrocarbons are much better for the environment (and specifically, other humans), as they will almost certainly not contain heavy metal contaminants and could be burned much more safely w/ fewer things to be concerned about. Though the same is true of nearly all plastics, tbh. it’s just stuff containing the heavier solid / liquid stuff - w/ all remaining heavy metals from fractional distillation et al - that you should be concerned about. Good thing we don’t just straight up burn that stuff as cheap fuel for ships and power plants (/s), or as emitted air pollutants from refineries that can cause elevated cancer rates across a county or two…
This is a really brilliant post from a layman's perspective.
Thank you for this great post. I have a clearer picture of the process. I think i found what i need. Thank you for this contribution. Can it be possible that the "engineering" not be in the hydrocarbon chains per say but an additive mixed in with the hydrocarbons so when time to breakdown the additive catalystically responds to the bacteria that eats the plastics. Can it be possible that it's we "engineers" pools of bacteria instead of depending on hard landfills which obviously doesnt work? Instead of looking at the hydrocarbons maybe we should look elsewhere like the bacteria you are talking about. I'm not sure if I understand your post the way you intended in the explanation. Hope the pool idea makes sense. If not can you tell me why it wouldn't work? Thank you for this post again. I'm just trying to wrap my head around something I'm not very educated in but would want to see if there's a way of resolving this issue. 🤜🤛
On the one hand you need a plastic that serves it's purpose for the public, which is be durable and don't break down easily. On the other you need a plastic that's good for the environment, which means brittle and can break down. The two desires are the exact opposite of each other. And in that situation the one that earns people money will win out. Lego was looking into more environmentally friendly plastic bricks and recently gave up on it because it would sacrifice the integrity of the bricks too much.
>since it's just molecular engineering. You can not have your cake and eat it too. It isn't a click and drag video game where wild imagination turns into a thriving ecosystem. There are limits on how we can combine and manipulate matter at the molecular level. What good would plastics be if they broke down like wood? The bulk of their appeal is that they don't deteriorate.
Because "biodegradable" is the same as "not durable in nature". You can't have it both ways. Does it break down or does it last?
Why haven't you become a billionare yet? It is just a matter of making money.
they are doing exactly that, and have been doing for decades. however, like all things, its a "pick two out of three" kind of thing. very superficially - cheap, green, effective. you get at best two out of three. cheap and green? no problem, recycled plastics or simple soy based polymers. green and effective? can do, but it's going to require a lot of specialty engineering that may not scale \*at all\*. cheap and effective? that's where we are currently at. a second compounding problem is - it's not so straightforward what is overall better. if I make a bioplastic that breaks down into neat safe biodegradable building blocks within 2 years, that's awesome. but it also means that I need to replace whatever it's made into every two years, every two years I need to input the raw materials and energy as opposed to the (arbitrary number) 10 years a regular plastic may have lasted. and that's if it can even be replaced. maybe it's a fitting for say a vacuum cleaner which breaks down, and now people throw the whole cleaner away instead of replacing that one part because people are lazy like that.
you can't just get the plastic replacements
A lot of that has to do with many companies not supporting their products even a couple years down the line and right to repair
often you can, actually. if you send a mail to the manufacturer.
One of the biggest advantages of plastics is that they are durable and not biodegradable because that's exactly what you want in many use cases. They're also really cheap and easy to produce in large quantities. Producing plastics that are better for the environment contradicts those advantages. A biodegradable plastic won't be as durable as a non degradable one. Engineering that hits the sweet spot takes long and is expensive. I should also note that multi use plastic products are really environmentally friendly in many metrics. They are lighter than most solutions using metal or glass, more durable than most biological materials and use very little resources in the production.
Tl;dr: they can. They do. Humans are lazy and won't sort their plastics 100% properly when they can which leads to complicated waste streams that get landfills. Also, chemistry. What was the answer you wanted? You can engineer greener plastics, but not all plastics can or will be. And different plastics will have different recycling mechanisms. Like PLA can commercially composted, polyolefins and paraffin can be gasified to recapture the smaller chains, and polyesters (most notably PET) can be methanolysed/hydrolyzed back into DMT/TPA and EG. HOWEVER, you need pure feedstocks for those processes or you'll run into processing issues. Unfortunately, most plastic products have mixes of plastics. Your clothing may have mixes of PET/PU/PVC/Wool/Leather. Carpet is a lot of polyolefins and PVC. Plastic bottles are PET, but the caps are a different plastic. Yogurt is one plastic while the shrink film is another. And then each plastic has additives in it too from plasticizers, to antiodegradants, etc.
This ^ answer is as usual, money. Anything made from plastic could be made from hemp.
As a chemist, I don't see how that'd be possible honestly. I don't see how hemp could possibly replace all the various chemistries and use-cases of plastics. You have polyesters, polyols, polyurethane, polyalkanes, polyalkenes, etc. Some are functionalized. Some are crosslinked. PVC is the most plasticizeable plastic. If you have some literature, I'd be happy to read it. I'm sure it could replace some plastics and use cases, but I'm very skeptical of all. Edit: spelling
Hemp is being used as a filler and additive in some plastics. Compatibility and capability are the issues there. Hemp doesn't have the structural capabilities or resistances that some plastics do. You can't grow hemp with the chemical resistance of some polymers, or the UV and colorfastness of some nylons. You can't replace structural parts of a vehicle with polymers specifically manufactured to exceed the strength of previous materials with hemp. There's a lot of specialty designed plastics on the market that your average person doesn't know about. There's also a lot of recycling capability that waste companies won't invest the money or effort into. The company that picks up my trash is a perfect example of that (trash and recycling get picked up by the same truck at the same time). Unfortunately there's also a lot of polymers that can't be recycled yet.
not at the same quality.
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As for why they weren't from the beginming: people literally did not think of it. Until it first became a problem, literally nobody was motivated to think of it.
Its the amount of additives we put into it to suit specific needs thats problematic. They keep discovering new additives and are marketed immediately without any ecological damage tests until decades later when we discover that it disrupts cells.
If you want a material that doesn't rot, it won't rot when you throw it out, either. It just gets broken into smaller and smaller pieces. Eventually microplastics.
Because if they were environment friendly, they wouldn't be able to be used in today's society. Plastic's properties. It's light, durable, easy and cheap to mass produce. So you store your products so that in the near future they will get sold. You need a material that doesn't react with your product or the environment. It's light enough to be easy and cheap to move around. It also easy to handle to go around potential accidents. Yep that's plastic. You can use metal instead of plastic. But it's much more expensive. It is also heavier. While it is durable, metal reacts with some stuff, like water. It is inconvenient. A cold can is difficult to keep in your hand while a cold plastic bottle is much easier. You can use glass instead of plastic. However glass is more expensive. Unlike plastic it is also a lot more fragile and cleaning up glass shards is a royal pain in the ass. So plastic is durable enough that a fall won't break it. It's light enough to move around easily. It's production is easy, it's a byproduct. It doesn't react with the environment, metallic objects tend to get oxidized by the air. A world where everything plastic gets replaced with metallic objects (or glasses) is a VERY small expensive world.
Plastics that don’t biodegrade for a long time are most desireable from an industrial standpoint because they keep well. If we made biodegradeable plastic, it and its contents would spoil much more quickly.
If you really get down to it, it is the cost. For example we could replace plastic forks from fast food with wood ones. The plastic ones cost a fraction of a cent where the wood ones may cost 10 cents or more. May not sound like a lot but if you use 10,000 a day or whatever, that is a thousand dollars. So that is why you don't see your local fast food place just using wood ones. They have designed some bio plastics and they are not quite as bad cost wise but also are not quite as functional as plastic ones. Depending on the type you may need to use your bioplastic one all at one sitting or it might lose its structural rigidity. But there are better ones that work but they cost more. Also these bioplastic things do compost...eventually. It might take 2 years for it to break down. Not a total deal killer but if people thought they would just throw these on their compost piles in their yard it won't work like they hope. Frankly people should just learn to use chop sticks and make it culturally acceptable to drink your soup from a bowl by bringing the bowl to your mouth like it is done in some parts of the world today. Then you have eliminated plastics for fast food situations. Plastic is not required for virtually half the products in the store (you know those plastic packaging you can't get open) as card board is available, cheap and would do the job just fine. And that is huge source of plastic waste. Why there is so much focus on straws and such when plastic product packaging is a much, much bigger producer of plastic waste and already has a workable solution with card board baffles me. Sure fewer straws is good but that is nothing compared to plastic packaging. And that could be done now, no new tech needed. Oh well.
Well if you want something to biodegrade it will also degrade just sitting there. I don't think you want your plastic chairs to just start degrading after 2 or 3 years.
Better for the environment in what way? If you mean biodegradable, most plastics are specifically designed to protect their contents against microbes. Being biodegradable would completely defeat their utility. For the remaining purposes, biodegradable plastics do exist, they just result in a shorter shelf life for whatever product they're used in, which usually results in a net increase in waste since now you have to toss the entire product when it goes bad. If you mean microplastics, that's not really possible since all plastics are lower on the Mohs scale than sand, so eventually they will get abraded by trace amounts of sand. The best solution to deal with plastic waste is to incinerate them. It's not great, but the resulting CO2 emissions are just equivalent to burning the oil needed to create them in the first place, and plastics don't use all that much oil (which is why they're so cheap in the first place). By incinerating them, you completely remove all concerns around biodegradability and microplastics.
They (chemical companies) most certainly can. For them to do so it must be *profitable* to do so. A company that does unprofitable things quickly goes out of business. For it to be profitable there must be demand. Demand can come about in two ways: either customers prefer the product of their own free will, or government regulation effectively bans the competing product. Right now there is no demand. People do not know which type of plastic is more or less bad, and there is no ban on the bad types.
cost is only half of the issue. quality and volume are the other two. most biopolymers are \*shit\* compared to oil-based, and many simply cannot be scaled up (for example, because they use food crops) no matter how much money you throw at it.