Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organics that are malleable and can be moldedinto solid objects of diverse shapes.

Benefits of plastics

The Plastics Industry Trade Association lists the benefits of plastic in modern life for building, aerospace applications, packaging, transportation and more.

Plastic is a relatively new material, invented originally from cellulose fibres in the 1850s, then from oil. As technology and manufacturing have developed the range and use of plastics has been integrated into every aspect of modern life.

Making plastics

Plastics are polymers, which are long chains of molecules made from smaller molecules called monomers. Plastics react to heat in one of two ways. Some soften and melt, and only return to a solid state when cool (e.g. polystyrene). These are called thermoplastics, and are made into things like bowls, buckets and packaging. Other plastics remain rigid when reheated - these are called thermosetting plastics - because their long molecule chains are criss-crossed. Most plastic products are made by moulding, either injection moulding or extrusion moulding.

Plastic bottles for water, milk, soft drinks or food are made from polyethylene terephthalate (PET) and are formed by extruding material into a preform, and then blow moulding the preform into a finished shape.

Polystyrene beads, containing trapped air, are moulded into light-weight packaging material, but hard to dispose of. If melted after use, they concentrate into heavier plastic pieces ready for recycling, as demonstrated by Ashburton Wastebusters in this photo:

melted polystyrne is heavy and compact


Although most plastics could be recycled, mixed plastics must be separated first into their different types. The Plastics Industry Trade Association designed an identification code to aid in recycling plastics.  The Identification Code, which shows the type of resin content, is a logo of three arrows, with the plastic type identified by a number in the middle. Plastics are grouped into 7 types, with the first six being the most common, and 7 for everything else. Some plastic products, mostly food, drink and detergent containers, are marked with these identification codes.

Recycling in New Zealand

Action and awareness in New Zealand

Plastic bottle kayak

The mission of the plastic bottle kayak campaign is to inspire New Zealanders to make positive change.  The expeditions are used to raise awareness and kickstart people into action.  See how you can be involved.

Keep New Zealand Beautiful

The Keep New Zealand Beautiful Beverage Container Recycling Community Grants, funded by The Coca-Cola Foundation, provides financial support to individuals, communities and organisations for projects which make long term improvements to the recycling of beverage containers.

Plastic Bag Free?

Annual effort to avoid disposable plastics, especially in food packaging and disposable supermarket bags.

How easy is it to reduce plastics use? Tina Ngata explains in this TV interview.

Other sources of consumer information and discussion on avoiding plastics include the Plastic is Rubbish website from the UK and the NZ blogs of Tina 'the non-plastic maori' and Matthew & Waveney's Rubbish Free Year.

In 2018 the NZ Government announced intention to ban single use plastic carrier bags and seeks public input on this.

Major Environmental Effects of plastics

Made from non-renewable resources

Modern plastics are made from oil and natural gas - both are non-renewable resources.

Byproducts of processing - when plastic is not so fantastic

Research points to the dangers of plastics to human health through both its production and disposal.  Chemicals, such as phthalates, bisphenol A (BPA), or polybrominated diphenyl ethers or PBDEs, may leach into food or water consumed by humans and into the natural environment. Although made from recycled plastics such as milk bottles (which seemed commendable at first), the plastic 'fleece' fibre jackets that are becoming common clothing items shed small fibres into water every time they are washed and these persist in nature. Natural fibres are not as environmentally damaging after use, as they can decay, but may also cause pollution at manufacture - such as bleaching of cotton.

Marine pollution accumulating

Many plastics do not break down, but break into smaller and smaller pieces causing rubbish to accumulate in the oceans. Small-sized particles, but large quantities, of indigestible plastics are entering river and marine food chains, and are found persisting all over the planet.

The Great Pacific Garbage Patch is the name given to the area containing plastics and rubbish trapped in the currents of the North Pacific Gyre.  Part of the Great Pacific Garbage Patch is the Eastern Garbage Patch estimated to be twice the size of Texas.

Cleaning up the garbage patch is a complex problem. The best solution is to limit or eliminate the use of disposable plastics.

Some organisations working on this are the Kiwi Bottle Drive,  Plastic Pollution Coalition and the Plastic Oceans Foundation. Listen to Sir David Attenborough talk about plastic pollution in our oceans.  A blog site about Impact of Single Use Plastics alerts you to problems and suggests responses.

Zero Waste Europe presents a short video on the extent of plastics washing onto beaches.

Marine Debris causes animal harm

Marine Debris can be very harmful to marine life