聚丙烯酰胺的改性和表征

用甲醛(F)和二氰二胺(D)改性聚丙烯酸胺(PAm),制得新型阳离子聚电解质PAm·MG,对PAm·MG的合成和表征进行了研究。合成反应通过两步进行,先使PAm与F反应,生成羟甲基化产物PAm·M,然后在酸性条件下使PAm·M与D反应,制得PAm·MG.控制F用量,得到不同取代度的PAm·M.和PAm·MG。PAm·MG在水溶液中能与阴离子聚电解质形成复合物沉淀证明PAm·MG带有阳离子基团。元素分析及电位、浊度滴定结果表明PAm·M中的羟基完全与D发生了反应。SALLS测得的M_w证实了PAm在改性过程中分子链未发生降解。

MODIFICATION AND CHARACTERIZATION OF POLYACRYLAMIDE

A new cationic polyelectrolyte has been synthesized by the modification of polyacrylamide (PAm) with formaldehyde (F) and dicyanodiamide (D). Methylol polyacrylamide (PAm·M) was first formed by the reaction of PAm with F in basic medium, then the cationic polyacrylamide (PAm·MG) was formed by the further reaction of PAm·M with D. Products of various content of methylol group or cationic group could be obtained by controlling the molar ratio of F. The structure and composition of both PAm·M and PAm·MG were identified by IR spec-trum and elementary analysis. The content of methylol group in PAm·M was examined by iodometry. The charge density of PAm·MG was determined by conductometric titration and turbidimetric titration,and Mw by small angle laser light scattering method.