商用聚丙烯酸类高吸水树脂粒子尺寸及分布与其凝胶浓度的关系

研究了6种商用聚丙烯酸类高吸水树脂(SAP)粒子尺寸大小及分布对其形成凝胶的临界浓度的影响,通过傅里叶变换红外光谱、X射线光电子能谱对样品的成分进行了分析,使用光学显微镜和ImageJ软件统计了样品未吸水时粒子的尺寸及分布,通过测定样品吸水后的膨胀比,估算得到了样品吸水后的粒子的尺寸及分布,用流变学方法和倒置实验法测定了高吸水树脂形成凝胶的临界浓度(凝胶点)。结果表明,这6种商用聚丙烯酸类高吸水树脂吸水后的粒子的尺寸大小对其形成凝胶的临界浓度的影响不符合理论预测,这是由于粒子尺寸分布宽度不均一造成的。在选择粒子大小分布占优的均一范围内,样品的凝胶浓度随着粒子尺寸的增大而降低。

Relationship Between Particle Size and Distribution of Commercial Polyacrylic Superabsorbent Resin and Its Gelation Concentration

The effects of particle size and distribution of six commercial polyacrylic superabsorbent resins(SAP) on the critical concentration of gel formation were studied. The compositions of the samples were analyzed by infrared spectroscopy and X-ray photoelectron spectroscopy. The size and distribution of particles of dry samples were counted by using polarized light microscopy and ImageJ software, and were estimated by measuring the expansion ratio of the sample after water absorption. The critical gelation concentration of these superabsorbent resins was determined by rheological method and inverted experiment. The results show that the effect of the particle sizes of the six commercial polyacrylic superabsorbent resins on gel formation is not consistent with the corresponding theoretical prediction, which is caused by the uneven width of the particle size distribution. In the uniform range dominated by particle size distribution, the critical gelation concentration of the sample decreases with the increase of particle size.