基于协同氢键作用的高强度聚乙烯醇聚丙烯酸水凝胶?

利用一些大分子和原位聚合形成的高分子链间的协同氢键作用可以构筑高强度水凝胶.本文以聚乙烯醇(PVA)为大分子模板,通过丙烯酸(AA)的原位聚合得到了一种高强度PVA-in situ-PAA凝胶,探讨了反应体系中PVA和AA配比对凝胶形成及力学性能的影响.结果表明,少量PVA的引入即可大幅度提高凝胶的力学性能,且凝胶的拉伸强度、模量断裂伸长率以及回弹率等均随PVA含量的增加而增加,其拉伸强度可达0.9 MPa,断裂伸长率均在2 000%以上.该类凝胶还具有优异抗应力松弛特性,在高的拉伸倍率(1 500%)下其应力保持率可达90%以上.

Tough polyvinyl alcohol-polyacrylic acid hydrogels based on cooperative hydrogen bonding

Tough hydrogels can be fabricated by cooperative hydrogen bonding between pre-existing polymer and in situ polymerized polymer chains.Tough PVA-in situ-PAA hydrogels templated on PVA were synthesized.Effect of feeding ratio (c(PVA)/c(AA))on formation and mechanical properties of hydrogels was studied.Low concentration of PVA enhanced significantly tensile strength, modulus and elongation of hydrogels;further enhancement was seen with increasing PVA content.PVA-in situ-PAA hydrogels exhibited excellent mechanical properties,with tensile strength up to 0.9 MPa and elongation of more than 2000%.Such hydrogels also showed excellent resilience and stress relaxation behavior,as indicated by high resilience ratios of more than 80%,retained stresses more than 90% under large extension up to 1500%.