Synthesis Of Functionalized Polyethylene By Half-sandwich Scandium Complex

Functionalized polyethylene materials have the advantages of lower density,cheaper price and more stability of original polyethylene.At the same time,their flexibility,surface properties,adhesion and miscibility with other polymers have also been improved,especially New functions are developed for photoelectricity,medical,ion exchange,etc.The research on functionalized polyethylene synthesis has always been the focus and hotspot of polyolefin research.In this thesis,we carried out the research on the binary and ternary copolymerization of ethylene with 10-dimethylsilyl-1-decene and styrene catalyzed by scandium monocene,and obtained polyethylene containing"Si-H"active groups.The hydrosilylation reaction yields functionalized polyethylene with different polar groups.1.The copolymerization of ethylene with Decene-SiH under 1.01×10~5Pa of ethylene has also been successfully achieved at room temperature.The copolymerization activity reached up to 10~5 g of polymer(mol of Sc)~-11 h~-11 and the conversion of Decene-SiH reached up to 99%.The ethylene/Decene-SiH copolymers with controllable compositions(Decene-SiH content=8~50 mol%),high molecular weight(M_n=7.2×10~4~10.0×10~4)and narrow molecular weight distribution(M_w/M_n=1.35~1.63)were conveniently obtained by changing the feed of Decene-SiH.When the Decene-SiH content of the copolymers was less than 12 mol%,the isolated insertion of Decene-SiH into polyethylene chain was achieved.When the Decene-SiH content of the copolymers was more than 26 mol%,the isolated and continuous insertion of Decene-SiH into polyethylene chain was also achieved.The ethylene/Decene-SiH copolymers with different compositions possessed a melting point(118°C~130°C).The ethylene/Decene-SiH copolymer possessed a glass transition temperature at-71°C when the Decene-SiH content of the copolymer was 50 mol%.The ternary copolymerization of ethylene,styrene and Decene-SiH has also been successfully achieved and a series of molar content can be adjusted with high activity(molar content of styrene 7~30 mol%,molar content of ethylene 67~92 mol%,molar content of Decene-SiH 3%)Decene-SiH/styrene/ethylene terpolymer.2.The"Si-H"group in the ethylene/Decene-SiH copolymers occured hydrosilylation reaction with allyl glycidyl ether,N,N-dimethylacrylamide,p-N,N-dimethylaminostyrene and methyl methacrylate under the Karstedt's catalyst.Under mild conditions,100%conversion of the"Si-H"group in the ethylene/Decene-SiH copolymer is achieved,and the"Si-H"group in the ethylene/Decene-SiH copolymer is converted to polarity efficiently Group,four functionalized polyethylenes with hydrophilic properties were obtained.No other side reactions occur before and after functionalization.Functionalized polyethylene still has a narrow distribution of high molecular weight,and the melting point of functionalized polyethylene does not change much.