对市售热塑性弹性体SEEPS产品的剖析研究OA

Given the absence of domestic SEEPS production,this paper selected three commercially available imported products from the same SEEPS series to investigate their structure,properties,and synthesis mechanism.The structure and properties of these products were characterized by NMR,DSC,GPC,and ICP,and they were compared with a synthetic sample.The experimental results show that the three products exhibit Mn of(9-24)×104,polydispersity index less than 1.13,unimodal distribution,nearly 100%hydrogenation degree of diene segments,a butadiene-to-isoprene mass ratio of approximately 30∶40,styrene content of 28%-30%(w),elongation at break more than 500%,and a glass transition temperature of approximately-58℃.The crystallization temperature and melting temperature increase with the increasing molecular weight of the products.The hydrogenation catalyst system consists of an organic acid nickel as the main catalyst and triisobutyl aluminium or triethyl aluminium as the co-catalyst.Further analysis indicates that SEEPS is obtained by first performing anionic polymerization to produce a styrene-isoprene/butadiene-styrene block copolymer(SIBS)and then catalytic hydrogenation of SIBS.In this process,styrene and the conjugated dienes(i.e.,butadiene/isoprene)are added separately,while butadiene and isoprene are added together in a one-step feeding method.