Preparation of End-Reactive Monodisperse Polyamide by Living Anionic Polymerization of Lactam

在N，N-二甲基甲酰胺中，25 ℃下，各种内酰胺的N-酰基衍生物如双环内酰胺（1）及其相应的单环内酰胺、ε-己内酰胺和2-吡咯烷酮与正丁胺进行氨解反应。胺与1的N-苯甲酰基衍生物中的外环和内环羰基都发生了反应。相比之下，在相同的条件下，只有单环N-苯甲酰基内酰胺中的环外羰基发生反应。双环骨架中的高空间应变和1中邻近羰基的醚基的电子效应可增强其聚合性，1在二甲基亚砜中进行阴离子聚合，在25 ~ 51 ℃温度范围内，所得聚酰胺与残余单体之间存在平衡，无副反应发生。从聚合体系中分离得到的具有酰基内酰胺型可增长链端的亲水性聚酰胺。在上述阴离子聚合中，使用N-苯甲酰基BOL和吡咯烷酮钾（分别为2和0.5mol%至1）在二甲亚砜中于25 ℃下制备单分散亲水性聚酰胺。聚酰胺的数均分子量与单体转化率成正比地增加，并且与由消耗的单体和活化剂的量计算的值一致。聚合中期（聚合时间<10 min，单体转化率<60%）所得聚酰胺分子量分布较窄（Mw/Mn = 1.1）。聚合后期分子量分布逐渐变宽。

Aminolysis of N-acyl derivatives of various lactams such as bicyclic lactam (1) and its corresponding monocyclic ones, epsilon-caprolactam and 2-pyrrolidone, with n-butyl- amine was carried out in N,N-dimethylformamide at 25ﾟC. The amine reacted with both of exo- and endocyclic carbonyl groups in the N-benzoyl derivative of 1. In contrast, only the exocyclic carbonyl group in the monocyclic N-benzoyllactams reacted under the same conditions. High steric strain in the bicyclic skeleton and electronic effect of ether group adjacent to the carbonyl group in 1 may enhance its polymerizability.The anionic polymerization of 1 proceeded in dimethyl sulfoxide with no side reaction and the equilibrium between the resulting polyamide and the residual monomer was observed at a temperature range of 25 to 51ﾟC. The resulting hydrophilic polyamide having an acyllactam-type growable chain end was isolated from the polymerization system. The terminal acyllactam group was chemically modified to various reactive groups such as vinylbenzyl group, carboxyl group and so on.The preparation of a monodisperse hydrophilic polyamide was achieved in the above-described anionic polymerization with the use of N-benzoyl BOL and potassium pyrrolidonate (2 and 0.5 mol% to 1, respectively) in dimethyl sulfoxide at 25ﾟC. The number-average molecular weight of the polyamide increased in direct proportion to the monomer conversion, and was consistent with the value calculated from the amounts of the consumed monomer and activator. The molecular weight distribution (MWD) of the polyamide obtained until the middle stage of polymerization (polymerization time, <10min; monomer conversion, <60%) was found to be narrow (M_w/M_n = 1.1). The MWD was gradually broadened in the later stage of the polymerization.