大孔PAMPS/PVA半互穿网络型水凝胶的制备及其性能研究

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

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240min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12.0MPa;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0.2mol·L-1NaCl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.

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 inhomogeneous 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 decreased 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 NaCI 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.