羧基中和程度对聚丙烯酸钠分散性能的影响

Effect of the degree of carboxyl neutralization on the dispersivity of polyacrylate sodium

采用自由基溶液聚合的方法合成了低分子量的聚丙烯酸 ,使用 3 0 %的NaOH将其中和为不同pH值的聚丙烯酸钠并用于钛白粉的分散。通过旋转粘度和最终沉降高度考察了羧基中和程度对于体系分散性能的影响 ,并用相差显微镜观察了微观分散相。结果表明羧基的中和程度越大 ,体系分散性越好 ,最佳pH值≈ 9

Low molecular weight poly(acrylic acid) was synthesized by radical aqueous solution polymerization. Then 30% NaOH was chosen to neutralize it into polyacrylate sodium with different pH values which were used to disperse titanium pigment. The effect of degree of carboxyl neutralization on the dispersivity of the system was observed through the rotational viscosity and final settling height. Moreover, the phase differential microscope was used to determine the microscopic dispersion phase. All results show that deeper the degree of carboxyl neutralization, the better the system dispersivity, and the optimum pH value is about 9.0.