摘要
研究了笼形聚羧酸钒(PV)-硫脲(TU)体系在硝酸溶液中引发丙烯腈(AN)聚合动力学。表观聚合速度(R_p)是 R_p=9.7×10~5e^(-10500)/RT[AN]~1.0[PV]~0.50[TU]~0.76[HNO_3]~1.5聚合诱导期(τ)随反应条件而变化,聚合温度越高,引发种浓度越大,聚合诱导期越短,但与单体浓度的变化无关。 1/τ=4.6×10^(12)e^(-13500)/RT[AN]~0[PV][TU]^(-3/2)[HNO_3]~3=K_τ·R_i聚合物分子量随单体浓度增大而提高,但随聚合温度及引发种浓度增大而下降,即 笼形聚羧酸钒—硫脲体系引发丙烯腈聚合的动力学参数和引发机理与杨梅型聚羧酸钒—硫脲体系在相同的条件下引发聚合的行为有明显的区别,认为是和两种树脂大分子链的空间结构所引起的传质阻力有关。
The kinetics of polymerization of acrylonitrile in aqueous nitric acid initiated by 'cage' vanadium (Ⅳ) polycarboxylate-thiourea system has been investigated. The overall rate of polmerization is: R_p =9.7×10~5e^(-10500/RT[AN]^1.0[PV]^0.50[TU]^0.70[HNO_3]^1.5 The induction periods of polymerization vary with the reaction conditions. The relationship between the induction period and the temperature as well as the concentration of initiating species can he written as: 1/τ=4.6×10^e^(-13500/RT)[AN]~0[PV][TU]^(3/2)[HNO_3]~3=K_τR_i The molecular weights of polymer increase with increasing monomer concentration, and decrease with increasing temperature of polymerization and the concentration of initiating species, i. e., M_n=K·1/T·[AN]/[PV]^(1/2)[TU]^(3/4)[NHO_3]^(3/2)=K_m·R_p/R_1 Under the same conditions, the difference of the rate parameters and the polymerization mechanism between the 'arbutus' and the 'cage' supporters were believed that it depends on the mass transfer effect arisen from the different chain configurations of the two matrices in reaction medium.
出处
《广州化学》
CAS
1991年第3期1-13,共13页
Guangzhou Chemistry
