Researches Of Structure Modified Polyisoprene Catalyzed By Neodymium System

Structure modified polyisoprene was synthesizd by polymerization of isoprene with Nd(vers)3,Al(Et)2Cl and Al(i-Bu)3 as its component in the presence of structure modification agent A or B.The effect of addition amount of the structure modification agent and the method of catalyst aging on branching structure,microstructure,molecular weight and molecular weight distribution,intrinsic viscosity,and solution dynamic viscosity of copolymers were investigated.And also the mechanical properties of these structure modified polyisoprene were studied.The addition of structure modification agent A had little influence on polymerization activity and microstructure content.With the increasing of addition amount of structure modification agent A,the dynamic viscosity decreased and molecular weight and polydispersity increased.The branching coefficient g of polymer was less than 1.Study on the influence of catalyst aging method on polymerization showed that polymerization activity increased when little Ip was added in catalyst aging and when structure modification agent B was added in catalyst aging,polymerization activity declined dramaticlly.With the increasing of addition amount of structure modification agent B,the conversation,dynamic viscosity and intrinsic viscosity of PIp decreased and molecular weight and polydispersity increased when structure modification agent B was added in catalyst.GPC-MALLS-Viscometer Analysis System proved the presence of branched structure in polymer.Research on polymer mechanical and rheological properties showed that mooney viscosity of blends was declined and processability was improved.when structure modification agent was added in the polymerization.The presence of the branched structure lead the polymer possess a higher activation energy of viscous fluid flow.By introducing the structure modification agent,tensile strength and tearing strength of the vulcanizate was increased,the storage modulus rised and loss factor fell.