Bioplastics

Biopolymers and Polymers Applications

Polymers have properties that make them suitable for use in protecting products from moisture, increasing shelf-life and making products easier to dispense. Every biopolymer has its own material-specific properties, e.g. barrier properties such as oxygen permeability. The barrier properties are relevant to the choice of biopolymers for the packaging of particular products. Bioplastics have very promising prospects for use in pesticide soil pins, for packaging in-flight catering products and for packaging dairy products.

Sugar based biopolymers Applications: Polyalctides decompose harmlessly in the human body and have therefore long been used for medical applications. Examples include surgical implants which do not require operative removal. Until recently, it was not feasible to use polylactides for packaging because of their high price, around US$500 per kilogram.

Cellulose based Biopolymers Applications: Familiar applications of cellophane include packaging for CDS, confectionary and cigarettes. The material is gradually falling out of favour, however, owing to its high price (about US$6 per kilogram). Other cellulose polymer materials (e.g. cellulose ilm) have also been commercially available for many years but are losing market share to newer polymers such as polypropylene.

Synthetic based Biopolymers Applications: The relatively high price of biodegradable polymers of synthetic substances, e.g. aliphatic aromatic copolyesters has prevented them from reaching a large scale market. The best known application is for making substrate mats.

The major advantage of biodegradable packaging is that it can be composted. But the biodegradability of raw materials does not necessarily mean that the product or package made from them (e.g. coated paper) is itself compostable. Biopolymers can also have advantages for waste processing. Coated paper (with e.g. polyethylene) is a major problem product for composting. Although such materials are usually banned from inclusion in organic waste under separate collection schemes, some of them usually end up nonetheless in the mix. The paper decomposes but small scraps of plastic are left over in the compost. The adoption of biopolymers for this purpose would solve the problem