大孔PAMPS/PVA半互穿网络型水凝胶的制备及其性能研究

以PEG6000为成孔剂, 合成了大孔聚(2-丙烯酰胺-2-甲基丙磺酸)/聚乙烯醇半互穿网络型(s-IPN)水凝胶. 红外分析表明, PVA与PAMPS之间形成了较强的氢键, 使得PVA分子上的C—O伸缩振动吸收峰移向了低波数处. X射线衍射分析发现, 当PVA用量较高时, 由于部分的PVA结晶, 使得凝胶的半互穿网络结构不均匀. 电镜分析结果表明, 没有使用成孔剂的凝胶表面成褶皱形, 不存在任何孔洞结构; 而以PEG6000为成孔剂的凝胶表面存在相互贯穿的大孔结构. 研究了该水凝胶的溶胀性能, 结果表明, 该水凝胶的平衡溶胀度在116至320之间; 而成孔剂PEG6000的加入能较大幅度提高凝胶的溶胀速率, 凝胶在240 min之内就能达到溶胀平衡. 对凝胶抗压缩性能的研究表明, 当PVA用量为9.1% (w)时, 凝胶的抗压缩强度最大, 可达12.0 MPa; 而成孔剂的加入会在一定程度削弱凝胶的抗压缩强度. 该凝胶具有较好的电场敏感性, 研究发现, 将吸去离子水达到溶胀平衡的凝胶放入施加有电场的0.2 mol•L－1 NaCl溶液中时, 凝胶迅速偏向阳极. 而PVA和成孔剂PGE6000的用量均对凝胶的偏转速度以及最大偏转角存在较大的影响.

Preparation and Property Characterization of Macroporous PAMPS/PVA S-IPN Hydrogels

Semi-interpenetrating polymer network (s-IPN) hydrogels composed of poly(vinyl alcohol) (PVA),and poly(2-acrylamido-2-methylpropylsulfonic acid) (PAMPS) were prepared by radical polymerization using PEG6000 as pore-forming agent during the reaction process.Fourier-transform infrared (FT-IR) spectroscopy was used to confirm the chemical structure of the s-IPN hydrogels,in which the peak of C-O stretching flows to low wave numbers.This was attributed to the formation of strong hydrogen bond between PVA and PAMPS.The crystallinity properties of s-IPN hydrogels were investigated by X-ray diffraction spectrography (XRD).The results show that the s-IPN structure of the hydrogels becomes inhomoge-neous when the dosage of PVA is high because of the crystallization of PVA.SEM macrographs revealed that a macroporous structure was formed with the addition of pore-forming agent PEG6000.The swelling properties of the s-IPN hydrogels were studied,showing that the equilibrium swelling ratio of the s-IPN hydrogels ranges from 116 to 320.The swelling speed of the s-IPN hydrogels increased significantly with the addition of PEG6000,and the hydrogel could reach its equilibrium swelling ratio within 240 min.Stress strength of the s-IPN hydrogels was also studied,showing that when the content of PVA was 9.1% (w),the hydrogel reached its maximum stress strength (12.0 MPa).However the stress strength of the hydrogels de-creased with increasing the dosage of PEG.This s-IPN hydrogel exhibits significant electrical sensitivity,when a piece of deionized water swollen hydrogel was placed in 0.2 mol·L~(-1) NaCl solution under an applied voltage,the hydrogel bent toward the anode quickly.Further investigation shows that both the bending speed and the maximum bending angle of the s-IPN hydrogels were influenced by the dosage of PVA and PEG.