四氯化钛/三异丁基铝体系催化降冰片烯与异戊二烯的共聚合

以传统Ziegler-Natta催化体系TiCl4/Al( i-Bu)3催化降冰片烯(NBE)和异戊二烯(IP)的共聚合,制得可溶于常规有机溶剂的共聚物,其数均分子量为2.0× 104 ～6.5×104,分子量分布指数为1.5 ～2.9,降冰片烯结构摩尔含量为26％ ～60％.考察了助催化剂用量、聚合温度及2种单体投料比对共聚合的影响.结果表明,当降冰片烯与异戊二烯的投料摩尔比为4∶6时,于40℃聚合6h,得到的共聚物产率为96％,数均分子量为6.5×104,降冰片烯结构含量45％.用1H NMR,13CNMR,GPC和DSC等方法表征了共聚产物的微观结构与热性能.13C NMR DEPT结果表明,共聚反应中降冰片烯单体以加成方式聚合.DSC结果显示,共聚物只有一个玻璃化转变温度(Tg=20 ～40℃).通过Kelen-Tüd(o)s方法得到2种单体的竞聚率分别为rNBE=0.07,rIP口=0.44.

Copolymerization of Norbornene with Isoprene Catalyzed by TiCl4/Al (i-Bu) 3 System

Copolymerization of norbornene(NBE) with isoprene(IP) catalyzed by traditional Ziegler-Natta system composed of TiCl 4 and Al(i-Bu) 3 was studied.The PNBE-co-IP copolymers obtained have number-average molecular weights of 2.0×104-6.5×104 as well as relatively narrow molecular weight distribution from the range of 1.5 to 2.9,and soluble in common organic solvents.The influences of catalyst composition,polymerization conditions,and the monomer feeding ratio on the copolymerization were investigated.The copolymer with 96% yield,45%(molar fraction) of NBE,and number-average molecular weight of 6.5×104 can be prepared under the following optimum conditions: n(NBE)∶n(IP)=4∶6,n(Al)∶n(Ti)=5∶1,n(Monomer)∶n(Ti)=200∶1,40 ℃,polymerized in toluene for 6 h.The NBE content in copolymer can be controlled in the range of 26%-60% by varying the feeding ratio of comonomer,and the T g of the copolymer increased with the increasing of NBE content in copolymer.The microstructures of the obtained copolymers were confirmed by 1H NMR and 13C DEPT135 NMR,and indicate that the NBE monomer undergo an addition-type polymerization during the copolymerization with isoprene.The reactivity ratios of two monomers were determined to be r NBE=0.07 and r IP=0.44 by the Kelen-Tüds method.