Study On Dimethylamino In-chain Multi-functionalized Butadiene/Styrene Polymers

Carbon black (CB)-based polymer composites with good dispersity have extensive application prospect in the fields of conductive resins, high-performance automotive radial tires and the like. However, the current methods of polymer chain-end amino-functionalization for improving the CB dispersion, could not meet the requirements of the high performing of these materials. The aim of this dissertation is to design and synthesize dimethylamino in-chain multi-functionalized butadiene-styrene random copolymer. Firstly, we report investigations into living anionic copolymerization of styrene and1,1-bis(4-dimethylaminophenyl)ethylene (BMAPE), butadiene and BMAPE, and then living anionic terpolymerization of BMAPE with butadiene and styrene. And in-chain multi-functionalized polystyrene, polybutadiene and butadiene-styrene random copolymer were successfully synthesized with the dimethylamino groups introduced into the polymer chains quantitively and positionally. Furthermore, we study the structure-property relationship of the obtained dimethylamino in-chain multi-functionalized polymers. The method developed in this work provides an effective route to prepare the polymer-based composites containing finely dispersed CB.In-chain multi-functionalized polystyrene possessing definite dimethylamino groups along the polymer backbone, poly(styrene-BMAPE), has been designed and synthesized via copolymerization of styrene and BMAPE in benzene, using sec-butyllithium as initiator. The results of copolymerization of styrene and BMAPE showed that the styrene monomer reactivity ratio r1was53.4. And the number of dimethylamino groups along the polystyrene backbone was readily controlled by the amount of BMAPE and the polymer molecular weight. The morphology study of CB/poly(styrene-BMAPE) composites showed that such dimethylamino groups introduced into the polystyrene chains significantly improved the dispersity of CB in the corresponding composites.In-chain multi-functionalized polybutadiene possessing definite dimethylamino groups along the polymer backbone, poly(butadiene-BMAPE), has been designed and synthesized via living anionic copolymerization of butadiene and BMAPE. The results of the synthesis and thermal property of poly(butadiene-BMAPE) showed that the number of dimethylamino groups along the polybutadiene backbone was readily controlled by the type and amount of polar additives and the polymer molecular weight. The addition of polar additives, such as tetrahydrofuran (THF), decreased the butadiene monomer reactivity ratio, and thus was beneficial to promote the incorporation of BMAPE into the polybutadiene chains. And the incorporation of BMAPE resulted in an increase in the glass transition temperature of poly(butadiene-BMAPE). In-chain multi-fiinctionalized butadiene-styrene copolymers possessing definite dimethylamino groups abng the polymer backbone, poly(butadiene-styrene-BMAPE), have been designed and synthesized via living anionic copolymerization of BMAPE with butadiene and styrene, using THF as polar additive. The results of the synthesis of poly(butadiene-styrene-BMAPE) showed that the number of dimethylamino groups along the butadiene-styrene copolymer backbone was definitely controlled by the amount of BMAPE and the polymer molecular weight.The studies of the morphology and properties of CB/poly(butadiene-styrene-BMAPE) composites showed that the incorporation of1.1mol%BMAPE into butadiene-styrene random copolymer (Mn=200kg/mol) effectively improved the dispersity of CB in the corresponding composites. Thus, the mechanical and dynamic mechanical properties of CB/butadiene-styrene-BMAPE random terpolymer vulcanizates were significantly improved, i.e., the tensile strength and the elongation at break were enhanced by20%and59%, respectively; meanwhile the value of dynamic loss coefficient at0℃and60℃increased by30%and decreased by29%, respectively.