茂金属化合物/Zn/BDGE/MAO催化体系合成aPS-b-P(S-co-E)-b-PE嵌段共聚物的研究

SYNTHESIS OF aPs-b-P(S-co-E)-b-PE BLOCK COPOLYMERS CATALYZED WITH HALF-TITANOCENE/Zn/BDGE/MAO CATALYST SYSTEM

采用单茂钛化合物CpTiCl3,有机环氧化合物1,4-丁二醇二缩水甘油基醚(BDGE),金属锌(Zn)及甲基铝氧烷(MAO)为催化体系,通过自由基聚合和配位聚合机理合成无规聚苯乙烯-b-聚(苯乙烯-co-乙烯)-b-聚乙烯(aPS-b-P(S-co-E)-b-PE).探讨了温度、时间、乙烯压力及Al/Ti摩尔比对共聚合的影响.所得嵌段共聚物采用DSC,WAXD,GPC和13C-NMR等手段进行了表征.结果表明该共聚物是苯乙烯/乙烯嵌段共聚物,聚苯乙烯链段是无规的,聚乙烯链段具有结晶性.

By one-pot technique the copolymerization of styrene with ethylene promoted by a cyclopentadienyl titanium triehloride （ CpTiCl3 ） / 1,4-butanediol diglyeidyl ether （BDGE）/Zn catalytic system to yield a Ps- b-P（ S- co- E）-b-PE block copolymers was investigated via sequential monomer addition strategy in the presence of methylaluminoxane （MAO） as cocatalyst for the coordination polymerization stage. The effect of temperature, time, ethylene pressure and the ratio of Al/Ti in tool on the polymerization performance was discussed in detail. Basically, a Ps-b-P（S-co-E）-b-PE block copolymers was obtained, together with atactic polystyrene through the approach, which was determined by solvent extraction. The CHCl3-soluble product was determined by GPC, DSC, WAXD and ^13 C-NMR. The molecular weight distribution （MWD） of the copolymer varied slightly at the range from 1.71 to 2.11. The DSC result showed that the copolymer featured one glass transition temperature （for example Ts - 86℃ ） attributed to the Ts of aPs domains and one melting point （for example Tm= 114℃ ） attributed to the Tm of PE domains. The blocky microstructure of the copolymer was further confirmed by WAXD and ^13 C-NMR. These results indicated that the copolymer was consisted of amorphous a Ps segments, P（S-co-E） segments and crystalline PE segments.