丙烯酸十八酯的溶液聚合

Solution Polymerization of Octodecyl Acrylate

用溶液法合成聚丙烯酸十八酯 ,主要探讨了引发剂、单体、温度及溶剂对聚合反应的影响 .由实验得到以下主要结论 :在聚合反应初期 ,聚合反应速率与引发剂的浓度呈半级反应 ,与单体呈一级反应 ;聚合反应常数的指前因子 Aa=1 2 3.4,活化能 Ea=2 9.72 k J/mol;溶剂种类对聚合反应速率没有明显的影响 ;4种溶剂在聚合反应过程中的链转移常数的次序 :Cs( CCl4) >Cs( CHCl3 ) >Cs( ( CHCl2 ) 2 ) >Cs(甲苯 ) ;聚合物的平均相对分子质量主要是受溶剂的链转移作用控制的 .由于聚合物分子在不同溶剂所产生的不同黏度效应 ,对聚合物平均相对分子质量产生一定的影响 .

The solution polymerization reactions of octodecyl acrylate were carried out in four solvents of CCI 4, CHCI 3, C 6H 5CH 3 and (CHCI 2) 2. The factors of influencing the average relative molecular mass of polyoctodecyl acrylate are discussed. The following conclusions are drawn: (1) in the different solvents, the rates of polymerization reactions are directly proportional to the concentration of the monomer, and are also directly proportional to 0.5 power of the concentration of initiator; the factor of the polymerization reaction constant A a=123.4, activation energy E a=29.72kJ/mol. (2) under the experimental conditions in the paper, the rates of the polymerization reactions have little something to do with the molecular structures of the solvents. (3) the average relative molecular mass of polyoctodecyl acrylate is mainly controlled by the chain transfer of the solvents, and the sequencing of the chain transfer constants of the four solvents is Cs(CCI 4)>Cs(CHCI 3)>Cs(C 6H 5CH 3)>Cs((CHCI 2) 2). (4) because polyoctodecyl acrylate has the gel effect of different degree in different solvent, under the condition of higher coversion, the molecular structure of solvent has the influence of different degree on its average relative molecular mass.