多孔聚乙烯醇缩甲醛凝胶力学行为对含水量变化的敏感性  

MECHANICAL SENSITIVITY OF MACROPOROUS POLY(VINYL FORMAL) HYDROGELS TO WATER CONTENT

作　　者：曾尤[1] 王瑞春[1] 周本濂[1] 

机构地区：[1]中国科学院金属研究所,沈阳110016

出　　处：《高分子学报》2005年第3期363-367,共5页Acta Polymerica Sinica

基　　金：国家自然科学基金资助项目 (基金号 5 993 10 2 0 )

摘　　要：通过成孔剂法制备具有连通孔结构的聚乙烯醇缩甲醛凝胶(PVFM) ,研究其在吸水膨胀脱水收缩过程中力学行为对含水量变化的响应性.实验表明多孔PVFM具有很快的吸水 脱水速度,吸水80s内就可达到最大的平衡膨胀应力,干燥4h内其膨胀应力可降低95 % ;同时还发现多孔PVFM在脱水干燥过程中出现明显的体积回弹和膨胀应力回复现象,而且压缩模量在一定范围内随含水量的减少反而降低,分析表明这些与PVFM的多孔结构、弹性网络的状态有密切关系.Smart hydrogels have been applied widely as sensors and actuators in many fields, such as artificial muscles, drug control release, fluid control and so on. However, their further applications have been hindered by the slow respond rate and the critical surrounding medium. A macroporous nonionic poly ( vinyl formal) hydrogel (PVFM) sensitive to water content, was synthesized by adding pore-forming agent. It showed a satisfied swelling/deswelling rate with the change in water content due to the presence of interconnecting pores. The swelling pressure of this hydrogel in water may reach its maximum within 80 s, and the deswelling pressure of the swollen hydrogel may decrease to 5% of its initial value within 4 h in the process of air-drying. Comparing with the conventional dense hydrogel, the macroporous PVFM showed many different behaviors, the volume did not decrease with the loss of water, but a phenomenon of volume recovery occurred during the air-drying process. On the other hand, the compressive modulus of the macroporous hydrogel did not increase monotonously with the decrease of water content as that of conventional hydrogels did, but decreased about 47% at the initial stage of drying process. This abnormal behavior is mainly related to the load-bearing modes of macroporous gels is with different water contents. The rapid response of macroporous gels is attributed to the weaker interaction between polymer and water, the higher porosity and the elasticity recovery of network. Since the macroporous PVFM hydrogels show the rapid swelling/deswelling rate and the satisfied sensitivity of mechanical properties to water content, they have the large potentialities to be used as sensors and actuators in flow control I humidity control and so on.

关 键 词：聚乙烯醇缩甲醛 含水量变化 力学行为 凝胶 敏感性 膨胀应力 吸水膨胀 脱水速度 干燥过程 压缩模量 多孔结构 弹性网络 成孔剂 响应性 分析表 

分 类 号：O648.1[理学—物理化学]