This is a section on biopolymers, presented by the Biopolymers consulting team @ Energy Alternatives India.

Origin

Polymers are found in nature generally from plants and animals sources. These may be, for example, starch, cellulose, proteins or lignin that has a structural function for the plant or animal.

 

Classification

 

Note – The term ‘biopolymers’ (polymers which occur in nature) must be clearly differentiated from ‘bioplastics’ from which the products can be made in the same way as they can be made from conventional plastics.

What are Bioplastics?

A bioplastic is a plastic that is made partly or wholly from polymers derived from biological sources such as sugarcane, potato starch or the cellulose from trees & straws. Some bioplastics degrade in the open air, others are made so that they compost in an industrial composting plant, aided by fungi, bacteria and enzymes. Others mimic the robustness and durability of conventional plastics such as polyethylene or PET.

Bioplastics can be classified into –

Based on the degradability

• Biodegradable plastics (PLA, PHA, starch blends etc)
• Non-biodegradable (partially bio-based) products (bio-based PET, PE, blends of PLA with petrochemical polymers)

Based on the degree of substitution

• Drop-ins – Drop-in plastics are non-biodegradable materials, obtained from renewable raw materials that present identical technical properties to their fossil counterparts. They are (partly) biobased, non-biodegradable commodity plastics such as PE, PET, or PP.
• Non Drop-ins – Non Drop-ins are materials that may or may not be biodegradable but they don’t have identical technical properties to their fossil counterparts. They include PLA, PHA, Bio-PA, etc.

 

	Biodegradable	Non-Biodegradable
Drop-ins	None	Bio-PET, Bio-PE, Bio-PP
Non Drop-ins	PLA, PHA, Starch & Cellulose based	Bio-based Polyamide Bio-Polycarbonate

Note – 

Biobased plastics may or may not be biodegradable plastics.

Biodegradable plastics may or may not be produced from renewable resources.

In fact it is a general misconception that biobased plastics are automatically biodegradable and vice versa.