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在苯乙烯单体聚合转化率不超过50%情况下,得到本体热聚合引发反应速度与单体浓度三次方呈线性关系,如果添加引发剂偶氮二异丁腈则其聚合速度与引发剂的0.5次方呈正比。根据Arrhenius 方程式求得的苯乙烯热聚合活化能 E_α=110.5kJ/mol,在引发剂 AIBN 存在下的活化能 E_α′=65.3kJ/mol。引发剂的存在促进游离基生成,加快聚合反应进程,使聚合物分子量分布较宽。添加十二碳烷硫醇作链转移剂,也有使聚合物分子量分布变宽和降低分子量的趋势,添加量超过0.2%则使聚合速度降低。另外,低温聚合的聚合物分子量大,分子量分布均匀。
In the polymerization of styrene monomer conversion rate of not more than 50%, to obtain the thermal polymerization initiation reaction speed and monomer concentration cubic linear relationship, if you add the initiator azobisisobutyronitrile its polymerization rate and the initiator 0.5 is proportional to the square. According to Arrhenius equation, the activation energy of styrene for thermal polymerization E_α = 110.5kJ / mol and the activation energy E_α ’in the presence of initiator AIBN = 65.3kJ / mol. The presence of initiator promotes the formation of free radicals, accelerating the polymerization process and widening the molecular weight distribution of the polymer. Addition of dodecanethiol as a chain transfer agent also tends to broaden the molecular weight distribution of the polymer and reduce the molecular weight, and the addition of more than 0.2% decreases the polymerization rate. In addition, low temperature polymerization of polymer molecular weight, molecular weight distribution.