IMPROVED IMPACT STRENGTH OF STYRENE-METHYL METHACRYLATE COPOLYMER SHEET BY GRAFTED DEPROTEINIZED NATURAL RUBBER

摘要

This research was studied to improve impact strength of styrene-methyl methacrylate copolymer sheet (S-co-MMA sheet) by using deproteinized natural rubber (DPNR) as an impact modifier. High Ammoniated Natural rubber latex (HANR) (60% DRC) was prepared to protein removal by sodium dodecyl sulphate (SDS) and followed by centrifugation. The influence of various sodium dodecyl sulfate and speed of centrifugation were investigated. Then grafted styrene and MMA onto DPNR via emulsion polymerization (DPNR-g-S/MMA). The effects of DPNR-g-S/MMA were studied by varying the amount of SDS and redox initiator. The DPNR-g-S/MMA was used as impact modifier in S-co-MMA sheet and studied the impact strength of S-co-MMA sheet. The result demonstrated the total lowest nitrogen content at 0.034±0.01% with SDS 1.0 phr, centrifugation at 12,000 rpm. Moreover, grafting efficiency of DPNR-g-S/MMA was higher than NR-g-S/MMA which transmission electron micrograph was found core-shell particle in DPNR-g-S/MMA, by DPNR as core and S/MMA as shell. The result was corresponding in increasing impact strength of S-co-MMA with DPNR-g-S/MMA. The hardness Shore D was decreased because of DPNR-g-S/MMA was an elastomer which shifted the brittle S-co-MMA sheet to ductile property. The smooth fracture surface of S-co-MMA sheet with DPNR-g-S/MMA was found in scanning electron micrographs which assured that DPNR-g-S/MMA could be able to improve impact strength and compatibility in S-co-MMA sheet.