การใช้ยางธรรมชาติกราฟต์สไตรีนเป็นสารช่วยผสมในการหล่อฟิล์มพอลิเมอร์ผสมระหว่างยางธรรมชาติ/พอลิสไตรีน / สุพัฒน์ มูลสิน = Use of styrene grafted natural rubber as a compatibilizer in casting natural rubber/polystyrene blend films / Supat Moolsin
Natural rubber/polystyrene blends with weight ratios of 70/30, 60/40 and 50/50 were casted into films by the solution-casting technique using toluene as a casting solvent. Properties of these blends were improved by using natural rubber graft styrene (NR-g-styrene) as a compatibilizer. In this research, graft copolymers with molar ratios of NR/styrene 90/10, 80/20 and 70/30 were prepared via emulsion copolymerization using tert-butyl hydroperoxide/tetraethylene pentamine (TBHPO/TEPA) as an organic redox initiator. The obtained graft copolymers were added to the blends with the amount of 0, 5, 10, 15, 20, 25 and 30 phr. After film formation, mechanical and morphological properties were investigated. It was found that the film prepared from NR-g-styrene 80/20 showed higher tensile and tear strength, moreover, morphology obtained from optical microscope showed finer domain size of the dispersed phase than those from NR-g-styrene 90/10 and NR-g-styrene 70/30. However, at high loading of the graft copolymer, themechanical properties of the blends decreased. In addition, thermogravimetric analysis revealed that weight loss was found to decrease on the introduction of the compatibilizer.