The rapid growth of plastic production is considered as a serious source of environment pollution from their wastes. Approximately 100 million tons of plastics are produced each year. Within a short period of time almost half of them are disposed to the environment [1]. In recent years, researchers have paid attention on discovering an alternative way to solve the problems by replacing the commodity synthetic polymers with biodegradable polymers. Among various kinds of biodegradable plastics discovered, poly(lactic acid), PLA, is the most promising polymer due to its excellent mechanical properties and biodegradability behavior