wk5-Biodegradation_of_Plastics_1 生物降解材料介绍.ppt

BIOREMEDIATION & BIODEGRADATION Lecture Week 5 Biodegradation of Plastics By Puan Norhayati Abdullah Biodegradation of Plastics Plastic? Synthetic polymers can be classified as plastics, elastomers and synthetic fibers. Plastics is the general term for a wide range of synthetic or semi synthetic polymerization products. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or reduce costs. Plumbing, textiles, paint, floor coverings at home are mostly made of synthetic polymers, some of which are described as plastics. The term ‘polymer’ are derived from Greek words meaning “many parts”. Polymers are macromolecules built up from linked smaller molecules called monomers. Plastics Benefits of using plastics: Low cost Strength (physically strong): lightweight and do not break like glass Durability Printability Plastic Uses Some common synthetic polymers chemical structures The Problem Public concern about the long term effects of plastics technology. Barry Commoner in late 1960s suggested that the earth surface would be buried ten feet deep in plastic waste because there were no biological organisms capable of destroying it. Plastics are the most common man-made object sighted at sea. During a 1998 survey, 89% of the trash observed floating in the North Pacific Ocean was plastic. Plastic sheeting has been documented in the stomachs of sperm whales, round-toothed dolphins and a Curvier beaked whale. Many sea turtles frequently swallow plastic bags when they mistake them for jelly fish, which is one of their favorite foods. The lightweight nature of plastics which can make them deadly in the marine environment, as plastic items can float on the surface of the ocean or within the water column. Plastics are composed of long chains of hydrocarbons, which are hydrogen and carbon atoms that are bound together very tightly. Micro-organisms such as plankton do not have the ability to break down