PVA-PAMPS-PAA三元互穿网络型水凝胶的合成及其性能研究

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)以及聚乙烯醇(PVA)为原料,制备了PVA-PAMPS-PAA三元互穿网络型(T-IPN)水凝胶.红外分析表明,PVA与PAA以及PAMPS之间形成了较强的氢键,使得PVA分子上的C—O伸缩震动吸收峰移向了低波数处.X射线衍射以及电镜分析表明,当PVA用量较低时,PVA能均匀的穿插于凝胶网络中,形成完善的互穿网络结构,当PVA用量过高时,部分的PVA结晶而使得凝胶出现相分离.研究了该三元互穿网络型水凝胶的溶胀性能,结果表明,该水凝胶的平衡溶胀比在200至340之间,并且随着AA以及AMPS用量的增加,凝胶的溶胀速率以及平衡溶胀比均升高.该三元互穿网络型水凝胶在酸性溶液中和在碱性溶液中表现出截然不同的消溶胀性能;并且随着溶液pH的升高,凝胶在pH=9.0附近出现体积突变,表现出pH敏感性.通过研究T-IPN水凝胶的抗压缩性能发现,利用线型高分子、柔性高分子网络以及刚性高分子网络制备的三元互穿网络型水凝胶能在高溶胀比下保持较高的强度.溶胀比为180的T-IPN水凝胶,其最大抗压缩强度可达12.1 MPa.进一步研究发现,凝胶的组成以及溶胀比均对凝胶的抗压缩强度和压缩应变均存在较大的影响.

SYNTHESIS AND PROPERTIES OF PVA-PAMPS-PAA T-IPN HYDROGELS

Ternary interpenetrating polymer networks(T-IPN) hydrogels composed of poly(vinyl acohol)(PVA),poly(acrylic acid)(PAA) and poly(2-acrylamido-2-methyl propyl sulfonic acid)(PAMPS) were synthesized by solution polymerization of acrylic acid(AA),2-acrylamido-2-methyl propyl sulfonic acid(AMPS) and PVA.Fourier-transform infrared(FT-IR) was used to confirm the chemical structure of the T-IPN hydrogel.In FT-IR spectra,the peak of C—O stretching shifts to low wave numbers.This is attributed to the formation of strong hydrogen bond between PVA and PAA and PAMPS.The crystallinity properties of T-IPN hydrogels were investigated by X-ray diffraction spectrogram(XRD) and scanning electron microscope(SEM).The results show that the hydrogel forms perfect IPN networks when the content of PVA is low.However,when the content of PVA is high,the crystallization of PVA increases,and phase separation is formed.The swelling properties of the T-IPN hydrogels were studied,the results show that the equilibrium swelling ratio of the T-IPN hydrogels ranges from 200 to 340.The T-IPN hydrogel exhibits completely different deswelling properties in acid solutions and basic solutions,and this T-IPN hydrogel exhibits discontinuous volume phase transition when the pH of the solution is about 9.0.The compression strength of T-IPN hydrogels was also studied.The results show that T-IPN hydrogels composed of linear polymer,flexible polymer network and rigid polymer network exhibit both high swelling ratio and high compression strength.When the swelling ratio of the T-IPN hydrogels is 180,the maximum compression strength of the hydrogel is about 12.1 MPa.Further investigation shows that the compression strength and compression strain are influenced by the composition and the swelling ratio of the hydrogels.