PVA改性PAMPS-PAM超高力学性能双网络水凝胶的制备

SYNTHESIS OF PAMPS-PAM DOUBLE NETWORK HYDROGELS MODIFIED BY PVA WITH SUPER HIGH MECHANICAL PROPERTIES

采用紫外光引发聚合制备了聚乙烯醇(PVA)改性的聚(2-丙烯酰胺基-2-甲基丙磺酸)-聚丙烯酰胺(PAMPS-PAM)双网络(DN)水凝胶.测定并比较了PVA改性前后PAMPS-PAM双网络水凝胶的溶胀动力学;通过扫描电子显微镜(SEM)观察了单网络水凝胶的结构;测定PVA改性前后PAMPS-PAM双网络水凝胶的压缩及拉伸性能.结果表明,经PVA改性后的PAMPS-PAM双网络水凝胶有较高的溶胀比;0.82%PVA用量的PAMPS-PAM双网络水凝胶在90%压缩形变率下仍保持完整、最大拉伸应力达到0.5 MPa,大幅提高PAMPS-PAM双网络水凝胶的力学性能.

Double network（DN） hydrogels composing of poly（2-acrylamido-2-methylpropanesulfonic acid） （PAMPS） as the first network and poly（acrylamide）（PAM） as the second network,which were prepared by ultraviolet irradiation polymerization,were modified by poly（vinyl alcohol）（PVA）.By adding the solution of PVA（0.82%） into single network（SN） hydrogels,tiny networks have been made in the PAMPS network structures.DN hydrogels modified by PVA become tougher and harder than those without PVA.The swelling behavior was measured gravimetrically at room temperature（25℃）.The structures of SN hydrogels modified by different amounts of PVA were successfully characterized by scanning electron microscopy（SEM）.The compressive and tensile properties of hydrogels were examined by using Zwick /Roell tester.The results showed that the DN hydrogels modified by PVA exhibited higher swelling ratio than that of unmodified DN hydrogels.Furthermore,with the increase of PVA solutions’concentration the swelling ratio was increasing.SN hydrogels modified by PVA（0.82%） showed tiny networks in the SN structures.Tiny networks enhanced the mechanical properties of the DN hydrogels.Photos of SEM demonstrated apparently that tiny networks only were found when the amount of PVA is 0.82% and 1.64%,however,the tiny network structures of SN hydrogels modified by 0.82% PVA were more regular than those of the SN hydrogels modified by 1.64% PVA.Some aspect of the compressive and tensile properties hand been enhanced,for example when the amount of PVA is 0.82%,the compressive stress of modified DN hydrogels was 12.8 MPa at 90% compressive strain （still keep integrity）,while that of the unmodified ones was 8.7 MPa at 80% compressive strain.Almost 78.6% enhancement of tensile stress compared with unmodified DN hydrogel indicated that the modified DN hydrogels had become tougher and harder.