Thesis (M.Sc.)--Chulalongkorn University, 2007

The objective of this research is the investigation of recycled ABS which was reused. This work will be used as information for the plastic manufacturing industry. The study was separated into two cases. First, the regrind from injection manufacturing process 1[superscript st] – 6[superscript th]recycled will be investigated and the physical properties of each recycled ABS will be studied. Aging condition was carried out at 90 degree celsius 72 hrs in order to simulate one to two years of actual use. It was found that increasing number of generations has effect on the physical properties such as, melt flow index slightly decreases, impact strength clearly decreases, elongation at break decreases, flexural strength and flexural modulus and glass transition temperature increase. Degradation of polymer from the manufacturing process will transform the molecular structure such as viscosity, mechanical properties etc. Consequently, the sample was blended between virgin with 6[superscript th] recycled ABS to improve the physical properties. Second, the repelletized resin obtained from 6[superscript th] recycled ABS was blended with the ratio of 0, 20, 40, 60, 80 and 100% by weight of virgin material. It was found that increasing quantity or ratio of repelletized resins has effect on the physical properties such as, melt flow index slightly decreases, impact strength clearly decreases, elongation at break decreases, flexural strength and modulus increase and glass transition temperature increases.