Scientists have figured out way to make algae-based plastic that decomposes | Hacker News Reader

Scientists have figured out way to make algae-based plastic that decomposes

abcnews.go.com

44 pointsxbmcuser34 comments

This is specifically a biodegradable polyurethane. It's just one kind of plastic and not suitable for everything.

We have others including old stuff like cellophane, pPLA, PGA, PGL, PHB even biodegradable polyesters... They're cheap. They can be fiber reinforced as needed. However...

The tricky bit is that almost always they need to be properly composted to decompose. This is called procedure 7 and cannot be usually applied to plastics that have a pigment added or are painted - the additives would poison the compost heap or leech. You need to be particularly choosy about paints and plasticizers if you want it to decompose safely.

Another problem is the cost. Mostly in energy. We have had these sugar cane or corn starch based biopolymers for years that nominally degrade to nothing, the reason nobody uses them (except facts-not-required corporate greenwashing purposes) is that the amount of energy you have to spend to get the input processed to the required state lies very much within the "totally ridiculous are you kidding" range.

Also, it turns out if you can't leave your packaging on the shelf for awhile and have it maintain a known state, it's less useful than the other stuff. Especially in developing countries with limited infrastructure (which is where the volume is) and where supply chains are likely to be exposed to high temperature and humidity which is exactly the environment required for accelerating breakdown...

This is the question I come back to: a crucial advantage of plastic is that nothing eats it. What’s the missing step that allows things to eat it, but only when we’re ready for them to?

Perhaps long term exposure to the fungisphere? Perhaps the breakdown should be by fungal digestion to inert bio-molecules not physical abrasion to forever-threatening microplastics. But I'm neither a chemist nor a microbiologist, just an amateur dilettante retro-industrialist roboticist.

People say "hey it should degrade" but the problem is degrading generally means worse properties. If you think about the qualities of polymers in actual use... at least in the food chain ... a thin layer allows water tightness, resistance to high temperatures (>100°C), thin deposition so materially efficient. This is hard to match with a "discard in to nature without fear" material. The best match is actually .. palm leaves, which - surprise, surprise - are a recognised packaging and water-proofing material in a large number of premodern cultures. The fallback option in evidence with such cultures (still in India) is low-grade pottery, which result by physical abrasion in dirt.

Perhaps we should just train a plant to grow watertight, microwave safe noodle bowls and be done with it.

We have plans for (millions) of HPDE sea floaters which should last for 10-20 years (structural strength is not a major issue iirc)

Is there a pathway to replace these with recycled plastic something?

would love for this to come fr9m OceanCleanup plastics somehow

Any thoughts on CO2 + Lignin for the same applications?

"CO2 and Lignin-Based Sustainable Polymers with Closed-Loop Chemical Recycling" (2024) https://onlinelibrary.wiley.com/doi/10.1002/adfm.202403035

- https://news.ycombinator.com/item?id=40079540

(Edit)

"Making hydrogen from waste plastic could pay for itself" (2024) https://news.ycombinator.com/item?id=37886955 ; flash heating plastic yields Graphene and Hydrogen

"Synthesis of Clean Hydrogen Gas from Waste Plastic at Zero Net Cost" (2023) https://onlinelibrary.wiley.com/doi/10.1002/adma.202306763

I hope this works and gets cheap as the only way the world gets off plastic is we replace it with something else. Most humans are selfish and are not willing to make sacrifices for the greater good so the only way we move of plastic is we replace it.

This is one area i believe laws are needed to warp the market. If it costs $0.50 more to make a compostable container, you can bet most companies will buy the cheap plastic.

I’m shocked at the single use waste that can be found in the restaurant industry. One of my favorite places used plastic for everything: cutlery, plates, cups. Their trash bins would be filled every day, and for what? To save a few cents? I feel customer facing plastics should all be compostable as a first step, if also for its social awareness impact.

What’s the best way to develop good policy? Pin point a few industries with maximum benefit/minimum cost to legislate for and expand from there? Or write a more holistic law that the entire population could then collectively weasel around, but it would be “fair” and “make sense”?

They almost all are compostable these days, even sometimes wooden or paper. But the composting is irrelevant when the volume is enough to overwhelm the best compost heaps.

Reuse trumps recycling trumps biodegradability. But it apparently costs too much to wash normal metal utensils...

To be honest I feel like "compostable" is the next version of the little recycling symbols on plastic containers: technically true, but mostly impractical to the point of being pointless, but a way of kicking the can of true progress down the road.

>the only way the world gets off plastic is we replace it with something else. Most humans are selfish and are not willing to make sacrifices for the greater good

so true... people forget that plastic saved elephants because it offered a compelling ivory alternative and fossil fuels saved the whales by offering a cheaper alternative to whale oil.

Ivory and whale oil are renewables :)

Up to a point.

Yes, but it's an important point. Just because something is renewable in principle, it doesn't mean it's renewable in practice at scale. I think this is also true for some of the "but it's renewable" modern stuff.

They nearly weren't

So are fossil fuels if you wait long enough.

You mean the atmosphere will no longer have free oxygen? How are we supposed to burn the new fossil fuels?

i imagine we'll never hear about this again for one reason or another like most of these good news breakthroughs. regardless of new fancy alternative plastics, a government could easily solve this virtually overnight in whichever given country by telling companies "single use plastics are banned as of x date, you will find an alternative and eat the cost or you will stop selling your product". never underestimate the ability of companies to adapt at short notice when money is on the line. it really is that simple, as are most of the issues we face in this sort of category.

> a government could easily solve this virtually overnight in whichever given country by telling companies "single use plastics are banned as of x date, you will find an alternative and eat the cost or you will stop selling your product

People will find ways around this. The British government imposed minimum costs on plastic bags (they have to charge customers not give them out free), and sales of single use bags is down, but people are reusing reusable bags less to we are probably using more plastic: https://www.channel4.com/news/factcheck/no-plastic-bag-sales...

thats because most of the "reusable bags" are just slightly thicker single use bags and they're so cheap that they're basically free though, there's no denying that it's a very easily solveable problem.

>there's no denying that it's a very easily solveable problem.

Why don't you say what the solution is rather than vaguely gesturing at it? Is the solution to require "reusable " bags to be even thicker, so that they require even more resources to produce ?

any random person off the street could give you a half decent one right off the bat? it isn't a complicated issue at all. some things that would definitely help off the top of my head:

1. only offer robust but recyclable paper bags and don't offer plastic bags at all, and make them cost more

2. make the existing plastic bags much more expensive, like £2.50 instead of £0.05-£0.10

3. make some kind of reward system for using bags multiple times, extra clubcard points or some kind of discount

4. don't offer any bags at all and force the customer to figure it out

>it really is that simple

It's really not that simple. You going to shut the country down and make everyone poorer overnight to try to do this? You don't foresee any unintended consequences?

And where do people get the idea that "the government" can just do whatever they want, in spite of the electorate?

preventing the sale of cheese slices and microwave burgers isn't going to shut a country down, that is absolutely ridiculous.

are you asking where people get the idea that governments... make laws?

> Most humans are selfish and are not willing to make sacrifices for the greater good so the only way we move of plastic is we replace it.

But not you.

Did I say I was not human I include myself in most humans.

Probably only happens via regulation (with the political capital that is then burned due to those who are opposed to regulation)

In addition to being in one of the most beautiful places in the world, I love the time I spend in Hawaii due to how much work they've put into banning most single-use plastics. My hope is that it is a taste of the future.

The world won't get "off plastics", it is one of the most useful materials to exist and many things are near unthinkable without it.

Correct me if I am wrong but because petroleum byproducts are cheap we have ubiquitous plastics? Making plastic out of algae probably will never be as cheap unless it is subsidized

So what? If we want to make it illegal to render our population infertile through microplastics, then the argument that allowing microplastics is less expensive doesn't seem like it should win the day.

So then i guess the answer is gov subsidies, not a bad idea but also not something that always works

The solution is a carbon tax that properly prices the negative externalities of all products on the market.

But how do we decide on the negative externalities?

We aspire to account for them all and add more as we uncover them.

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