聚环氧乙烷对PAMPS/PAM双网络水凝胶结构和性能的影响

采用紫外光引发聚合制备了含聚环氧乙烷（PEO）的聚(2-丙烯酰胺-2-甲基丙磺酸)(PAMPS）/聚丙烯酰胺（PAM）双网络（DN）水凝胶。使用扫描电子显微镜（SEM）观察了PAMPS单网络水凝胶的结构；测定了PEO改性前后双网络水凝胶的压缩及拉伸性能。PEO改性DN凝胶的第一网络网孔上由于PEO片晶结构引起不同程度的褶皱，这种褶皱起支撑作用；PEO的分子量达到5万时，褶皱的支撑作用最佳，DN凝胶的力学性能最佳；DN凝胶的力学性能随PEO加入量先提高后下降，在PEO加入量为0.1%时，PEO片晶结构加固了DN凝胶的物理交联点，力学性能达到最大，压缩应力达到31.6 MPa；加入更多的PEO阻碍了第一网络的凝胶化，造成网络结构的不连续，从而使DN凝胶的力学性能下降。

Influence of poly(ethylene oxide) on structure and properties of PAMPS/PAM double network hydrogels

Double network(DN)hydrogels of poly(2-acrylamido-2-methylpropanesulfonic acid)(PAMPS)/ poly(acrylamide)modified by polyethylene oxide(PEO)were prepared using UV ray initiation polymerization.The structures of the first network hydrogels modified by different PEO solutions were observed with scanning electron microscopy(SEM).Compressive and tensile properties of the modified DN hydrogels and blank DN hydrogel were also determined.The result showed that many folds caused by PEO lamellae were irregularly distributed in the mesh walls of the first network hydrogels modified by PEO，and took part in the role of supporting mesh walls of the first network.When the molecular weight of PEO reached 50000，the supporting effect of folds was the best and mechanical properties of the DN hydrogels would reach a peak.As the amount of PEO increased，the mechanical properties of DN hydrogels were strengthened until the amount reached 0.1% then were weakened when the amount of PEO increased further. Lamellar structures of PEO chains reinforced the skeleton of the first network，which strengthened the compressive properties of DN gels to a maximum(31.6 MPa)，when the amount of PEO was 0.1%.However，further increase of PEO amount caused discontinuous structure of the first network，which resulted in a decline in the mechanical properties of DN hydrogels.