Starch based plastics
First Generation of biodegradable plastics came into market in 1980s from some North American entrepreneurs. It focused on single use disposables such as garbage bags, snap food wrappers and disposable plates. They were mostly polyolefin mixed with starch. So it was not completely biodegradable. This confused customers and regulators in the beginning.
Thermoplastic starch constitutes about 50 percent of the bioplastics market. Pure starch possesses the characteristic of being able to absorb humidity and is thus being used for the production of drug capsules in the pharmaceutical sector. Flexibiliser and plasticizer such as sorbitol and glycerine are added so that starch can also be processed thermo-plastically. By varying the amounts of these additives, the characteristic of the material can be tailored to specific needs.Starch can be derived from agricultural crops including corn, wheat, potatoes, tapioca, rice and soy and is both inexpensive and plentiful.
European research indicates starch based polymers offer energy and emission savings of 12-40 GJ/ton of plastic, and 0.8-3.2 tons of CO2 emissions/ton of plastic compared to one ton of fossil derived polyethylene.
Starch-based bioplastics are important not only because starch is the least expensive biopolymer but because it can be processed by all of the methods used for synthetic polymers, like film extrusion and injection moulding. Eating utensils, plates, cups and other products have been made with starch-based plastics.