As the world is waking up to environmental catastophe and peak oil, the plastics industry is being forced to look beyond short-term profit in the direction of the long-term future of the planet. More now than ever, manufacturing and sustainability in plastics is at the front of industry people’s minds.
Which direction are they looking?
Different ways of sourcing and processing plastics are the obvious way to start. Although they don’t alleviate our usage, at least they reduce landfill and CO2 emissions.
Biodegradable material can be in the form of an additive that you add to biopolymers or petro-chemical derived plastic, or pre-mixed material.
Manufacturing with recycled materials or regrinding waste material in house.
cheap and simple using existing infrastructures
economic savings for producers
inconsistent supply of “natural” light coloured material meaning most recycled materials need to go into black products.
low profit margin in producing recycled materials
On the surface, bioplastics seem to be the to answer all of our questions, but the industry is still evolving and materials not without issues.
PLA is produced from lactic acid produced by fermented corn or cane sugars and can be used to replace polystyrene. It’s a little brittle and not a very high quality plastic so only useful in some applications like food packaging. Other similar biopolymers include PCL and PGA.
PDO is made from glycerol derived from corn and cane sugars and can be used to replace PET or Nylon. PDO also has biomedical applications like surgical sutures, where it degrades inside the body.
PHB is produced by bacteria as energy storage in stressful conditions. It’s biodegradable, sinks in water, has good UV resistance but poor acid/alkali resistance. Production is expensive at the moment.
Bamboo fibres can be used to replace glass in reinforcing of plastics for engineering
Cellulose is the most abundant biopolymer on the planet. It can be obtained from plant matter and bacteria. Used already to make paper and cellophane. Slow production, uneconomical
Algae Oil is highly efficient, producing 10-100 times more fuel than other biofuel crops. Potentially useful as an alternative to petrolium oil as plastic source
At least carbon neutral in some cases carbon reducing – growing plants absorb CO2
Made from renewable sources
Often biodegradable or compostable
Many can be made from any starch sugar source
Quality inferior to most rigid polymers but suitable to 70% of applications
In some cases, composting is not natural but industrial, requiring special equipment
Recycling facilities not set up to recycle yet so biopolymers go in the landfill right now
Good product design can save material, energy and carbon dioxide in production and end use.
A reduction in wall thickness, using ribs for reinforcement, is quicker to manufacture and uses less material. Biopolymer additives can be used which strengthen existing materials meaning even less wall thickness than with conventional materials.
A snap fit design reduces the need for other components like glue or screws.
To paraphrase Henry Ford, you can have any recycled plastic colour, as long as it’s black. Due to the mixing of colours in the recycling stream, white or natural material is very hard to find, so very often the mix of colours is only consistently usable as black. Recycled material is cheaper and better for the planet, so why have white when black will do.
In the end, it all boils down to energy: how we get it and how we use it.
More efficient usage of energy can be through better part design and material choice. Machinery can also be upgraded for lower fuel costs, though this isn’t always economically viable.
Energy can be obtained from renewable sources, with or without government tax incentives. Energy can also be generated on site through technology like solar panelling.
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