Alternatives to Plastic

By Dr. Liji Thomas, MDMay 28 2018

Image Credit:Shutterstock/LarinaMarina

Introduction

Plastic is an essential part of our daily lives today. There are few materials which can match the flexibility, versatility, lightness, and affordability of plastic. But what we cannot ignore is the constantly increasing toll that this takes on our ecosystem. The very properties that make plastic so useful to us - durability, resistance to environmental degradation - are what make plastic so deadly to our world.

Problems with Plastic

Plastics are the common name for carbon-based polymers. They can be melted, molded, remelted, remolded, and so on almost forever. But one of the downsides to this is that a lot of that carbon comes from oil, and that’s not very good for the environment.

Another one of the problems that stem from our excessive uses of plastics is recycling - or the lack of it. Some plastics can be recycled, but very, very little of it actually is. Each year in the US, about seven billion tons of polyvinyl chloride plastic (known to most as PVC) is used. Only a quarter of a percent of this is recycled. Plastic waste is piling up at an alarming rate.

This waste plastic often leaches toxic chemicals into the surrounding water, where it can cause widespread disease and death in the surrounding creatures.

Pollution is one of the biggest downsides to plastic. Besides ordinary pollution, the processes involved in producing plastic from natural gas and oil belch tons of harmful chemicals into our ecosystem every day.

For all these reasons, we need an alternative to plastic. That conclusion was obvious. The hard part is finding an alternative - one that mimics the many pros of plastic without so many of the cons. There aren’t a lot of materials that do this. But there are a few, discussed in broad outline below.

Fungi

Unlike mushrooms, the type of fungi used for structural design isn’t edible. However, it is a worthy replacement to plastic. By using different techniques to culture the fungi, it is possible to grow reproductions of several materials, such as plastic, wax, and even cork. The micro-organisms are neutralised before the product is sold, so you don’t need to worry about your chair growing green stuff!

Liquid Wood

Liquid wood is a biopolymer: biopolymers are substances that look and act just like polymers, with one major difference: they’re biodegradable. It’s manufactured by mixing lignin (a plant byproduct of the paper manufacturing process) with water and then subjecting the mixture to heat and pressure. What comes out is a strong, flexible, moldable composite non-toxic material. Liquid wood can be used to create anything from toys to T-shirts.

Glass

Glass has been around for a long, long time. Sure, plastic is lighter. But on the flip side, glass won’t melt in your microwave. And glass is much easier to recycle. Glass doesn’t leach harmful chemicals into anything. It doesn’t take polluting materials or manufacturing processes: glass is made from sand. Glass could be very well be the alternative to plastic.

Biodegradable Plastics

Biodegradable plastics (BDPs) aren’t an alternative to plastic in the conventional sense – they are plastic. Only it’s biodegradable. The plastics that we commonly think of as “plastic” are actually aromatic polyesters. They’re very cheap and extremely flexible, but they’re also completely resistant to microbial breakdown – non-biodegradable.

These seem to be one way to go, being made of sustainable materials such as starch, milk or cellulose, and being capable of breaking down completely. These may be classified as biodegradable (or bioerodable) which break down into tiny particles, over months, or biocompostable which can be composted with other compostables. Both must end up as carbon dioxide, methane, water, inorganic compounds or biomass, predominantly by enzymatic action of microbes.

Types of BDP

They may be bio-based, or petrochemical-based. The bio-based type is produced from plants, animals or microbes, which produce polysaccharides like starch, lignin or cellulose, lipids such as plant or animal fats, and proteins such as gelatin, casein or gluten. Natural rubber, polyhydroxyalkanoates, and poly-3-hydroxybutyrates (both from microbes or plants), as well as polylactic acid (PLA) which comes from a bio-based monomer, lactic acid, also belong here.

Petrochemical-based BDPs include aliphatic polyesters such as polycaprolactone(PCL) and polyglycolic acid, aromatic copolyesters like polybutylene succinate terephthalate, and polyvinyl alcohol, which can be biodegraded. Polycaprolactone, commonly shortened to PCL, is an aliphatic polyester - it’s made from fossil fuels, but it can undergo complete breakdown in six weeks.

It’s already being used in stitches for precisely this reason. The main reason why it hasn’t been adopted on a wider scale yet is because of its high manufacturing cost. However, combining it with cornstarch can cut these costs. Hopefully we’ll see more PCL in the near future.

Many BDPs today contain a mixture of both categories for increased performance or cost-effectiveness.

These are some of the bio-friendly alternatives to plastic. None of them have become wildly popular yet, but with plastics taking an increasing toll on our environment, change may be in the offing quite soon.

Sources

1. https://science.howstuffworks.com/environmental/green-tech/sustainable/5-plastic-substitutes.htm
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873018/
3. https://www.ncbi.nlm.nih.gov/pubmed/28973963
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3791860/
5. https://www.ncbi.nlm.nih.gov/pubmed/24361447
6. https://friendsoftheearth.uk/plastics/9-really-good-alternatives-plastic

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