Preparation Of Acrylonitrile/Ammonium Itaconate Copolymer And Character Of Copolymer Solutions

Acrylonitrile (AN) polymers based precursors are polymerized by AN and some of comonomers, and itaconic acide (IA) is the most usually used. In our experimental, IA was treated by ammonia, and it formed an ammonium salt of IA, namely ammonium itaconate (AIA). Free-radical copolymerization of AN with AIA initiated by azodiisobutyronitrile (AIBN) were investigated in solution polymerization and aqueous suspension polymerization. It has been demonstrated that the copolymerization of AN and AIA in dimethyl sulphoxide (DMSO) conforms to the mechanism of radical polymerization. The conversion of copolymerization in DMSO is higher than that in dimethyl foramide (DMF).High molecular weight AN/AIA copolymers were obtained by aqueous suspension polymerization. Aqueous suspension polymerization conforms to the general law of free radical polymerization also. Values of the conversion and the viscosity average molecular weight of copolymers increase quickly and the molecular weight distribution becomes narrow with addition of the dispersant polyvinyl alcohol (PVA). As concentration of PVA is beyond 0.02wt%, the conversion and the viscosity average molecular weight of copolymers show a trend of decrease and the molecular weight distribution becomes broad. Because the lower solubility in organic solvent (such as: AN and DMSO), it is difficulty to increase the content of AIA in resulting copolymers obtained by solution polymerization and aqueous suspension polymerization technique.Aqueous deposited copolymerization initiated by ammonium persulfate [(NH₄)S₂O₈] can be used to polymerize AN/AIA copolymers. The copolymers have superior properties, such as: befitting AIA content, high molecular weight and narrow distribution. Because of different densities of monomer and water, the AN/AIA/H2O system was separated into two phases, monomer phase (AN phase) and water phase. AN phase partitions between the monomer and water phase. In polymerization process, AN was transported from monomer phase to water phase. It was found that conversion and molecular weight were decreased with the increase of monomer concentration. The molecular weight of copolymers was decreased with the polymeric time increased and with the increase of temperature. As temperature was higher than 55 ℃, the molecular weight of copolymers shows a trend of decrease. All of the exceptional phenomena were attributed to the transport of AN.Effects of AIA on copolymerization and structure and properties of copolymers were investigated. Because of different active of monomers, the polymer composition...