Thesis (M.Sc.)--Chulalongkorn University, 2006

Biodiesels produced from refining and used cooking oil were blended with diesel in 5% and 10% by volume. The effects of biodiesel blends on property change of six types of elastomers; NBR, HNBR, NBR PVC, acrylic rubber copolymer FKM and Terpolymer FKM, were compared with those of pure biodiesel and diesel. The immersion time is varied to 22, 670 and 1008 hours. Properties measured in this work include mass change, volume change, hardness change, tensile and elongation changes. At immersion temperature of 50 C, the experimental results showed that the properties of NBR, NBR PVC and acrylic rubber immersed in biodiesel were affected. The mechanical properties were deteriated. The extent of property changes were proportional to biodiesel concentration. For copolymer FKM, terpolymer FKM and HNBR, the properties changed slightly. At high temperature, 100 C, more significant change was observed in acrylic rubber, NBR and NBR/PVC. This is due to the obsorption of biodiesel by rubber in those samples. From the glass transition temperature measurement of acrylic rubber, the value decreased after immersed in biodiesel.