聚烯丙基氯化铵模板存在下丙烯酰胺-丙烯酸共聚合反应动力学研究

丙烯酰胺 (AM)和丙烯酸 (AA)模板共聚合是以聚烯丙基氯化铵 (PAAC)模板存在下 ,在水溶液中进行 ,在这体系中 ,模板PAAC和单体AA有很强的相互作用 ,而单体AM与模板则没有作用 .应用膨胀计和电导滴定方法研究了影响聚合反应速度的各种因素 ,得到的结果指出 ,在聚烯丙基铵模板作用下共聚合反应遵循Ⅰ型 (zip)模板聚合反应机制 ,速度最高值出现在模板单元T与单体AA等摩尔比 (T AA =1)处 ,这表明在反应溶液中PAAC和单体AA具有很强的相互作用 .测得它们的竞聚率分别为r1 =2 6 8(AA)和r2 =0 4 4 (AM) ,与没有模板存在时相比 ,大幅度增高的r1 值表明此共聚合反应 ,生成AA长序列结构的可能性大大增加 .同时发现聚合反应速度分别和单体浓度及引发剂浓度的 1 1和 0 83次方成正比 ,由于模板的作用数值高于常规值 .

KINETICS STUDY OF COPOLYMERIZATION OF ACRYLAMIDE WITH ACRYLIC ACID IN THE PRESENCE OF POLYALLYLAMMONIUM CHLORIDE AS TEMPLATE

Template copolymerization of acrylamide (AM) with acylic acid(AA) was carried out in the presence of polyallylammonium chloride (PAAC) as matrix in aqueous solutions.The various influences on the rate of polymerization were studied by dilatometer and electrical conductivity measurements.The obtained results indicated that the process of copolymerization under the effect of polyallylammonium salt was according to type I (zip) template mechanism.The maximum of reaction rate was appeared at equivalence mole ratio of template unit (T) to monomer AA.T/AA=1 indicated a high interaction between the monomer AA and the template in the solution.The reactivity ratios of r_1 2.68 for AA and r_2 0.44 for AM were also obtained.The considerable enhancement of r_1 compared with that without the template indicated that the presence of PAAC significantly increases the probability of long sequences of AA unites in copolymers.The rate of polymerization was found to be proportional to the concentration of monomers and initiator with exponents of 1.1 and 0.83, respectively,which are larger than the ordinary values due to the effect of PAAC.