以聚丙烯酸为分散剂制备高分散超细银粉

Preparation of highly dispersed ultrafine silver powders with polyacrylic acid as dispersant

为了改善银粉的分散性,以聚丙烯酸(PAA)为分散剂、AgNO3为原料、抗坏血酸为还原剂,通过化学液相还原法制备了高分散超细银粉。研究了pH值、温度和分散剂用量对所制银粉的粒度和表面形貌的影响。结果表明:反应液的酸碱度对银粉的表面形貌有很大影响,在pH值为2时,银粉为树枝状;pH值为4时,银粉为不规则的类球形;pH值为8时,银粉为规则的球形。分散剂的用量对银粉的粒度影响最大,随着分散剂用量的增多,银粉颗粒粒度越来越小。优化的最佳工艺为:pH值为8,温度为50℃,分散剂与硝酸银质量比为0.005。采用最佳工艺制得的银粉分散性最好,平均粒度为1.41μm。

In order to improve the dispersivity of silver powders,highly dispersed ultrafine silver powders were prepared from silver nitrate by chemical reduction method with ascorbic acid as the reducing agent and polyacrylic acid as the dispersant.The effects of pH value,temperature and dispersant dosage on the mean particle size and morphology of the ultrafine silver powders were studied.The results show that the pH value of the reaction solution shows significant effect on the morphology of the ultrafine silver powders.Dendritic,sphere-like and spherical silver powders are respectively obtained when the pH values of the reaction solution are 2,4 and 8.The dispersant dosage has the most significant effect on the particle size of the ultrafine silver powders,and the mean particle size of the silver powders decreases rapidly with increasing dispersant dosage.The optimized preparation condition is： the pH value equals to 8,the temperature is 50 ℃,and the mass ratio of dispersant to silver nitrate is 0.005.The silver powders prepared under the optimized condition show the best dispersivity with a mean particle size of 1.41μm.