When we use the word plastics, we mean polymers. Plastics is not a substance or material, it’s an attribute (plasticity).
Plasticity is the name used to describe the property, feature or attribute of all materials which can deform irreversibly without breaking. This attribute refers to the production process and not the usage. We can mould a polymer to give it a specific form (ex: a plate). The polymer survived the moulding and production process because of its plasticity.
What we refer to as plastics are usually organic polymers of high molecular mass mixed with other substances (additives). These polymers and additives are usually derived from petrochemicals except in the case of bioplastics…or shall we say biopolymers.
Biodegradation and Compostability
Bioplastics is also capable to biodegrade or decompose back into its natural elements, under the action of bacteria or enzymes (bio-degradable).
There’s a difference between biodegradation and composting. Biodegradation refers to a process that starts without human intervention and where the residue is not necessarily compost. Composting refers to a process started by human intervention and here the end redisue is used for compositing purpose. Read more on the difference between biodegradable and compostable.