Study On Toughed Styrenic Resins With Multi-functional Peroxide Initiators

In numerous processes of rubber toughing polystyrene,bulk polymerization process is a process of being developed and has broad prospects.With the advantages of short process, low-cost in installation building,transformation between HIPS and ABS production processes, and less "three wastes",it receives widespread concern.In this article,bulk polymerization of high impact polystyrene(HIPS) and acrylonitrile-butadiene-styrene copolymers(ABS) were carried out in the presence of 3,6,9-triethyl-3,6,9-trimethyi-1,4,7-triperoxonane(TETMTPA), with low cis-polybutadiene rubber as a rubber phase;Bulk polymerization of HIPS were also carried out with TETMTPA/TEMPO.The paper discusses the effect of various process conditions on polymerization reaction dynamics and phase transitions,the relevance of structure and performance of polymers.It was found that:1.In the bulk polymerization of HIPS initiated by TETMTPA,The average molecular weight of the product initiated by TETMTPA were higher than that of BPO both under the same amount of initiator and the same amount of functionality,the molecular weight distribution of the product initiated by TETMTPA were also narrower than that of BPO;as the polymerization temperature increases,the polymerization rate increases and the phase transiton take places earlier,tensile strength and elongation at break of the polymer decreases; as the initiator dosages increases,the polymerization rate increases,tensile strength and elongation at break of the polymer increases too;tensile strength,impact strenght and elongation at break of the polymer reach the maximum when the rubber dosage is 15%;when flexibilizer is different,the polymerization rate by descending order is 9004 rubber＞700A rubber＞720Arubber;the increasing amout of ethylbenzene is not conducive to improve the tensile strength,impact strength of polymers.2.In the bulk polymerization of HIPS initiated by TETMTPA/TEMPO,as the dosage of TEMPO increases,the polymerization rate decreases,phase transition stayed more or less the same,the molecular weight distribution becomes narrower,average molecular weight also shows a downward trend,impact strength and elongation at break of the polymer decrease.3.In the bulk polymerization of ABS,as the initiator dosage increases,the polymerization rate increases,phase transiton take places earlier,the acrylonitrile content and grafting ratio of the polymer increase too;the molecular weight distribution of polymers becomes narrower when the flexibilizer is 700A,9004,SIBR respectively;the polymerization rate initiated by tetra-functional peroxide initiator is higher than that of TETMTPA both under the same amount of initiator and the same amount of functionality;As the polymerization proceeding,cis-1,4 structure Reduced the maximum and Content of 1,2 structure in a small reduction,cis-1,4 structure content increased,cis-1,4 structure was much easier for grafting than 1,2 structure.