Thesis (M.Sc.)--Chulalongkorn University, 1999

The effects of type and quantity of additives on the resilience property of rigid poly (vinyl chloride) (PVC) thin sheet for Christmas tree products were studied. The additives studied in this research are methyl methacrylate butadiene styrene (MBS), acrylonitrile butadiene styrene (ABS), chlorinated polyethylene (CPE), processing aid, internal lubricant, calcium carbonate and talc. It was found that the best additive to improve the resilience property is ABS. The optimum amont of ABS for Christmas tree material is 10 phr. The resilience property of the new PVC formula is 2 times better than that of two commercial products. Increasing MBS, CPE, internal lubricant, calcium carbonate and talc decrease the resilience property. Processing aid dose not significantly improve the resilience property. Properties such as tensile strength, tear strength, hardness, heat distortion temperature (HDT) and glass transition temperature (Tg) were studied and it was found that the resilience property related to both hardness and tensile strength of blends.