Plastic is a wonder – it’s malleable, so it can be moulded into almost any shape, and at the same time it’s also durable and can resist wear and tear. Indeed, since synthetic plastic was first invented back in 1907, the world hasn’t been able to get enough of the stuff. According to one study, we’ve manufactured enough plastic since World War II to coat the entire globe in a layer of saran wrap.
The problem, of course, is that for all their benefits, the many plastics that aren’t biodegradable are devastating for the environment. So at a time when the world’s attention turns to changing the tide of plastic pollution, what are some of the more eco-friendly alternatives to this material?
Once upon a time we used glass storage for many items which are now stored or packaged in plastic. Unlike plastic, which often is derived from fossil fuels, glass is made from sand. This renewable resource doesn’t contain chemicals that can leach into your food or body and and it’s easily recycled – whether you throw bottles in your recycling bin to be turned into new bottles or reuse glass jars for storing leftovers.
Canvas, fiber, hemp, cotton & nylon
These materials are all alternatives to non-biodegradable plastic when it comes to shopping bags. When plastic bags first hit the scene, we still had a choice to use paper or plastic. Then, for many years it was almost impossible to find an alternative to plastic bags to carry your groceries home in. Now increasingly we can opt to use reusable grocery bags made of canvas, fiber, hemp, cotton, nylon – or even leather. In reality, any type of bag will do, whether it’s meant to carry groceries or not.
While some are busy developing plastic substitutes, others are bent on making conventional thermoplastics biodegradable by mixing in additives called prodegradant concentrates (PDCs). PDCs are usually metal compounds, such as cobalt stearate or manganese stearate. They promote oxidation processes that break the plastic down into brittle, low-molecular-weight fragments. Microorganisms eat up the fragments as they disintegrate, turning them into carbon dioxide, water and biomass, which reportedly contains no harmful residues.
Scientists say milk protein could help to produce a biodegradable plastic for furniture cushions, insulation, packaging and other products. With this method, casein, the principal protein found in milk, can be turned into a biodegradable material that matches the stiffness and compressibility of polystyrene.
Casein-based plastic has been around since the 1880s, when a French chemist treated casein with formaldehyde to produce a material that could substitute for ivory or tortoiseshell – however it was too brittle and so its use didn’t take off for it to be used in the way that we use many modern plastics. Now, however, scientists have found a way make the protein less susceptible to cracking and also less toxic by substituting glyceraldehyde for formaldehyde during the process.
Liquid wood is actually a promising new bioplastic, or biopolymer, which looks, feels and acts just like plastic but, unlike petroleum-based plastic, is biodegradable. This particular biopolymer comes from pulp-based lignin, a renewable resource. Manufacturers mix lignin, a byproduct of paper mills, with water, and then expose the mixture to serious heat and pressure to create a mouldable composite material that’s strong and nontoxic. German researchers have incorporated this plastic substitute into a variety of items including toys, golf tees and even hi-fi speaker boxes. and because it’s made of wood, it can be recycled as wood, too.
Polycaprolactone (PCL) – aliphatic polyesters (biodegradable polyesters)
Overall, these polyesters aren’t as versatile as aromatic polyesters such as polyethylene terephthalate (PET), which is commonly used to make water bottles. But since aromatic polyesters are completely resistant to microbial breakdown, a lot of time and effort is being pumped into finding viable aliphatic polyester alternatives. Polycaprolactone (PCL) is a synthetic aliphatic polyester that isn’t made from renewable resources but does completely degrade after six weeks of composting. It’s easily processed, but hasn’t been used in significant quantities due to manufacturing costs.
Polyhydroxyalkanoate (PHA) polyesters
There are two main members of this type of naturally produced polyester – polyhydroxybutrate (PHB) and polyhydroxyvalerate (PHV). While they’re less flexible than petroleum-based plastics, you can find them in packaging, plastic films and injection-moulded bottles.
Production costs have mostly put PHA in the shadow of cheaper, petroleum-based plastics, but a little creativeness in sourcing inexpensive raw materials may make it a top choice soon. Corn-steeped liquor, molasses and even activated sludge could all supply the sugar the bacteria need to produce this plastic. PHA polyesters also biodegrade via composting.
Producing plastic from processed corn may seem like a pipe dream, but it’s happening every day. Polylactic acid, or PLA, is another aliphatic (biodegradable) polyester and one that can be made from lactic acid, which is produced via starch fermentation during corn wet milling. Although most often generated from corn, PLA can be made from wheat or sugarcane as well. It decomposes within 47 days in an industrial composting site, won’t emit toxic fumes when burned, and manufacturing uses 20 to 50 percent less fossil fuels than petroleum-based plastic. Often, companies blend PLA with starch to reduce cost and increase its biodegradability.