聚合条件对聚甲基丙烯酸盐体系ER效应的影响

Influence of Polymerization Condition on Electrorheological Effect of Suspension Containing Salt of Poly(Methacrylic Acid)

用反相乳液聚合直接合成了具有高电流变（ＥＲ）活性的聚甲基丙烯酸盐（ＳＰＭＡＡ）的悬液。研究了影响ＥＲ效应的因素，结果阐明了该体系中的水分在ＥＲ效应中的作用。

Colloidal suspensions containing salts of poly(methacrylic acid ) which exhibit a high electrorheological(ER) activity were synthesized by inverse emulsion polymerization. The factors influencing the ER effect were studied. The results showed that the maximum yield stress occurred in the case where. optimum amounts of both polymeric stabilizer and crosslinking agent were used in the inverse emulsion polymerization as well as a certain water content of the particles, while yield stress increased with the increase of the average diameter of the particles below 0. 9 μm or the molar ratio of the salt to the acid. The ER activity for the suspensions containing different monovalent counter ions decreased in the following order:Li+>Na+>K+ > NH.The phenomena were discussed with the ionic polarization mechanism and the roles of the adsorbed water of the particles in the ER suspensions were elucidated.