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高吸水树脂在水泥基材料中的早期吸水与释水行为
作者: 明1 王育江2 王文彬1 张建亮1  倩1 刘加平2 
单位:1. 江苏苏博特新材料股份有限公司 高性能土木工程材料国家重点实验室 南京 211103 2. 东南大学材料科学与工程学院 南京 211189 
关键词:高吸水树脂 压榨孔溶液 吸水行为 释水行为 
分类号:TU528
出版年,卷(期):页码:2016,44(11):1595-1601
DOI:10.14062/j.issn.0454-5648.2016.11.08
摘要:

利用反相悬浮制备的球形高吸水树脂(SAP)在干燥及吸液过程中均能保持良好球形度的特性,基于图像统计分析,研究了SAP在不同早龄期压榨孔溶液中的吸水行为,同时利用毛细管压力和自收缩测试分析了SAP的早龄期释水行为。结果表明:压榨孔溶液离子浓度及pH值在凝结时间前后的3~4 h范围内相对稳定,1 d后pH值超过13.6,且孔溶液实际上由KOH和NaOH组成;SAP在水泥浆体早期的吸水与释水行为主要受渗透压控制,在压榨孔溶液中的吸液行为符合Fick扩散定律,且饱和平衡吸液能力随水化龄期的延长而逐渐降低;SAP在浆体凝结前已开始释水,且塑性阶段的快速释水导致后期的内养护效果不足。
 

Since the spherical superabsorbent polymers (SAP) synthesized by inverse suspension polymerization can well maintain a spherical shape at dried state and during the absorption process, the water absorption behavior of SAP in the different early-age extracted pore solutions was investigated by image statistical analysis, and the water release behavior was evaluated by capillary pressure and autogenous shrinkage tests. The results indicate that the ion concentrations and pH value of the extracted pore solutions are unchanged for 3–4 h before and after setting. The pH value exceeds 13.6 after 1 d and the extracted pore solution can be considered as a composition of KOH and NaOH. The water absorption and release behavior were both controlled by osmotic pressure, the absorption kinetics of SAP governed by diffusion can be analyzed by the Fick second law of diffusion, and the absorption capacity at equilibrium decreases with increasing the hydration age. SAP shows a sustained release property before setting of cement paste, and a rapid water release rate during plastic stage resulting in an insufficient internal curing effect.
 

基金项目:
国家自然科学基金(51578268, 51438003);国家“973”计划 (2015CB655105)资助项目
作者简介:
李 明(1990—),男,硕士,助理工程师
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