Non-biodegradable

Non-biodegradable describes a material that cannot be broken down by microorganisms such as bacteria and fungi, so it stays in the environment for a very long time. Most synthetic polymers, such as polythene and PVC, are non-biodegradable. Malay: tak terbiodegradasi · Chinese: 不可生物降解.

The reason synthetic polymers resist decay is that microorganisms have no enzymes able to attack their long carbon chains, which are not found in nature. As a result, plastic waste does not rot away like food or paper; it piles up in landfills, litters land and sea, and can harm wildlife. This single property is behind most of the environmental problems in the chapter, and it is why the responses, reducing, reusing, recycling and designing biodegradable plastics, are needed in the first place. Being non-biodegradable is useful in a product that must last, but a serious drawback once that product becomes waste.

Example. A polythene shopping bag dropped as litter stays almost unchanged for a very long time because no microorganism can digest it, whereas a paper bag beside it would be broken down by microorganisms in a matter of weeks.

Confusion to avoid. Do not confuse non-biodegradable with biodegradable. A non-biodegradable material cannot be broken down by microorganisms, while a biodegradable one can. Most ordinary plastics are non-biodegradable; food, paper and specially designed biodegradable plastics are biodegradable. The prefix “non-” flips the meaning, so read it carefully in a question.

In an extended-response question you may be asked to describe the environmental problems caused by non-biodegradable plastics and to suggest solutions. A strong answer names the persistence of the waste, the harm to land and marine life, and the loss of landfill space, then offers reducing, reusing, recycling and switching to biodegradable or photodegradable plastics.

Non-biodegradability is the central environmental idea of the Polymers chapter, linking the usefulness of plastics to the problem of plastic waste that SPM Chemistry expects you to discuss.