Study On High Performance ABS Resins Via Bulk Polymerization

In this thesis, acrylonitrile-butadiene-styrene (ABS) resin with superhigh anti-impact property was prepared via bulk polymerization method using styrene-butadiene-isoprene terpolymer rubber (SIBR) as toughener. "Network" structure and "contour line" structure were presented in linear random SIBR and starlike block SIBR toughening system, respectively. When their contents were 12% and 22%, the notched Izod impact properties of ABS resins were up to 468.0 J/m and 353.3 J/m, respectively. Meanwhile, toughening mechanism of SIBR with different structures was systematically investigated. And the relevant method for preparing the ABS resins with superhigh anti-impact property has been applied the China patent (201010110104.X).Based on the continuous bulk polymerization technics introduced into China, the bulk polymerization process and the relative rules between struecture and performances of ABS were thoroughly and systematically researched using the nickel catalyzed high cis-1,4 pobutadiene rubber (Ni-9004, Yanshan Petrochemical Rubber Co., China) and the lithium catalyzed low cis-1,4 polybutadiene rubber (Li-700A, Asahi Kasei Co., Japan) as compounded toughener, 1,1-bis(tert-butylperoxy)cyclohexane (DP275B) as free radical initiator. The optimum technological conditions for effectively control the polymerization reaction and phase inversion were summed up. The more the Li-700A content in compounded rubber, the smaller and more uniform the disperced rubber particles. When Ni-9004 and the compounded rubber with suitable blending ratio were used as tougheners, the comprehensive mechanical properties of ABS can match by ABS-8434. Moreover, polybutediene rubbers with different structures have been synthesized by active anionic polymerization technology, and were further used for comparison with commercial rubbers in order to establish the proper molecular and structural parameters of rubbers for toughening.In addition, the raletive rules between impact fracture behavior, morphological structures and morphology of fractured face of ABS were deeply and systematically studied. And the relevant theoretical relationship among the three aspects was established. With increasing the rubber content and Ni-9004/Li-700A ratio, a transition process from brittle to semi-ductile to ductile to superhigh toughness occurred for the fracture mode of materials. Accordingly, the fracture mechanisms transformed from cavitation, matrix peeling and rocklike patterns to shear yielding, parabolic patterns and ligament-forming and tearing, etc. Furthermore, in view of the uncontrollable bulk polymerization and the broad molecular weight distribution of the obtained polymer, the "live" free radical polymerization, grafting mechanism and structural morphology of Ni-9004 grafted polystyrene (PS) were systematically explored using 2,2,6,6-tertamethylpiperidinyl-l-oxy radical (TEMPO) as stable free radical, DP275B as iniatior. Adding an appropriate level of TEMPO can result in a controlled grafting polymerization rate and a steadily growing molecular weight of polymer.