摘要
本文采用透射电子显微镜(TEM)研究了低温PVA水凝胶的结构,直接观察到该体系呈明显的相分离结构,可将所形成结构视为聚集态水平上的宏观网络结构,认为正是这种网络结构的形成而赋予了体系强度和弹性.观察到,随着冷冻时间的增长,逐渐形成完善的网络结构,随着体系中PVA浓度的增大,网络结合得更加紧密.还从DSC测定了该相分离结构解体的热焓变化,进一步证实了显微镜的观察结果,提出了该体系凝胶化过程的宏观机制.
Cryo-hydrogel-rubbery elastomer, containing above 85% water was prepared by freezing aqueous solution of poly (vinyl alcohol) (PVA). Structure of cryo-PVA-hydrogel was studied by TEM. Experimental results showed that the cryo-hydrogel was a non-covalent bonded gel formed due to linking of polymer 'clusters'.Electron microscopy demonstrates the heterogeneous porous structure of the cryogel. It was found that the porous structure become more and more perfect with increasing the freezing time and polymer concentration. It is considered that phase separation plays an important role in gelation. The freezing is to encourage the phase separation and reinforce the mechanical strength.The results of DSC are in accordance with the results above.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
1992年第3期316-320,共5页
Acta Polymerica Sinica
关键词
低温水凝胶
网络结构
聚乙烯醇
Cryo-hydrogel, Network structure, Poly (vinyl alcohol)
