The Study On Plastics Degradation In Supercritical Water

Plastic is becoming one of the four kinds of mainstay material due to its excellent properties such as low density, great strength and corrosion resistance. However, the plastic wastes increase more and more as the fast development of plastic industry, and become a serious "White contamination" problem. As a novel method of waste treatment, supercritical water can decompose the waste plastic into valuable liquid, gas or solid, and solve the environment problem.In this work, the degradation of PS, PE, mixture of PS/PP and PE/PS in supercritical water were studied, and the influence of reaction temperature, time and ratio of water/plastic on the degradation was investigated.The results show that PS is the easiest to degrade, reaction temperature and time are the major elements effecting on the degradation, the yield of liquid products of PE and PE/PS mixture increases and gas's decreases with high temperature and long time. The degradation temperature of mixture should base on the more difficult material, the mixtures interact with each other, and increasing reaction time can speed the degradation, and the products vary with the reaction time.Liquid products under C7~C14, and gas products under C2~C5 can be gained through GC-MS analysis. The density and viscosity measure, and the effect of reaction temperature and time on the viscosity are also included in this paper, the liquid viscosity of PE and PE/PS mixture decrease with high temperature and long time.