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采用反相悬浮聚合 ,加碱水解 ,共沸脱水的方法合成了分子量达 10 7数量级的粉状、速溶阴离子型聚丙烯酰胺。确定最佳引发体系为K2 S2 O8 DM NaHSO3,适宜的反应温度为 35℃ ;研究了水解度与水解时间、水解温度、水解剂加量之间的关系 ,确定最佳水解时间为 40min ,水解温度为 5 0℃ ,碱与丙烯酰胺的摩尔比为 0 2。实验结果表明 ,适当增加有机溶剂可解决反应后期体系粘度大、易交联产生不溶物、不易成粉等问题。初步探讨了聚丙烯酰胺分子量的测定方法 ,认为采用乌氏粘度计一点法 ,在 2 5℃ ,0 2mol/LNaCl水溶液中测定样品的 [η],使 ηr=1 2～ 1 5 ,试样质量浓度≤ 0 5 g/L较好。[η]=kMα 中 ,k取 3 6 84× 10 -2 ,α取 0 6 46。
Anionic and anionic polyacrylamides with molecular weight of 10 7 were synthesized by reverse phase suspension polymerization, alkali hydrolysis and azeotropic dehydration. The optimal reaction system was K2 S2 O8 DM NaHSO3. The optimum reaction temperature was 35 ℃. The relationship between hydrolysis degree and hydrolysis time, hydrolysis temperature and amount of hydrolysis agent was studied. The optimal hydrolysis time was 40min, hydrolysis temperature Is 50 ℃, the molar ratio of base to acrylamide is 0 2. The experimental results show that adding appropriate organic solvents can solve the problems of high viscosity, easily cross-linked insoluble, difficult to powder and so on. The method to determine the molecular weight of polyacrylamide was discussed preliminarily. The [η] of the sample was determined by Ubbelohde viscometer method at 25 ℃ and 0 2 mol / L NaCl aqueous solution, so that ηr = 12 ~ 15, Concentration ≤ 0 5 g / L is better. In [η] = kMα, k is taken as 3 6 84 × 10 -2, and α is taken as 0 6 46.