D-山梨醇对聚丙烯酸-水基氧化铝悬浮液流变性能的影响

Effect of D-sorbitol on Rheology of Aqueous Alumina Suspensions with Poly(Acrylic Acid)

研究了D-山梨醇(D-sorbitol)对聚丙烯酸(poly(acrylic acid))(PAA)稳定的水基氧化铝(Al2O3)悬浮液流变性能的影响.实验发现:在pH为9.0时,对于固含量为30vol%～40vol%的Al2O3悬浮液,少量D-山梨醇的加入皆能明显提高其分散稳定性.当D-山梨醇的添加量占分散剂总量(0.5wt%)的20%时,悬浮液粘度最低.且添加二元分散剂PAA/D-山梨醇的悬浮液具有更好的抗电解质性能.分别对单一PAA分散的Al2O3及二元分散剂分散的Al2O3进行了红外光谱表征.结合流变与红外实验结果,分析了山梨醇的作用机理:部分山梨醇吸附在Al2O3颗粒表面,部分山梨醇与PAA以氢键形式结合,增大了颗粒间的空间位阻,提高了悬浮液的流变性能.

Effect of D-sorbitol addition on rheological properties of aqueous alumina suspensions dispersed with poly （acrylic acid） （PAA） was investigated. The results showed that for the aqueous alumina suspensions with 30vol%-40vol% solids loadings, small amount of D-sorbitol can significantly enhance the stability of alumina suspen- sions with PAA at pH=9.0. When the total amount of dispersant was 0.5wt% and the concentration of D-sorbitol was 20%, the viscosity of suspensions was the lowest. In addition, the suspensions dispersed with binary dispersant were less sensitive to ionic strength than the suspensions containing just the PAA. The role of PAA and D-sorbitol in the alumina suspensions was characterized by FTIR spectroscope. Based on the rheology and FTIR measurements, a schematic model was established to depict the mechanism for the effect of D-sorbitol in the presence of PAA. D-Sorbitol was absorbed both on alumina surface and the absorbed PAA, leading to an enhanced steric hindrance thus resulting better stability of the suspensions.