聚乙烯醇/膨润土杂化水凝胶的力学性能和溶胀行为

利用冷冻-解冻法制备了聚乙烯醇/膨润土杂化水凝胶. X射线衍射结果表明，膨润土以剥离形式分布在水凝胶基体中. 研究结果表明，与纯PVA5水凝胶相比，经过5个冷冻-解冻循环制备的含2%(w)膨润土的杂化水凝胶的拉伸模量、拉伸强度和断裂伸长率分别增加了44.0%, 74.2%和25.2%，而溶胀行为与5个循环的纯水凝胶相近. 含0.5%(w)膨润土的杂化水凝胶的拉伸模量和拉伸强度高于基体水凝胶，其在溶胀400 min时的溶胀度高于所有的样品.

Swelling and Mechanical Behavior of Poly(vinyl alcohol)/Bentonite Hybrid Hydrogels

Bentonite was added into PVA hydrogels to modify the mechanical properties. A series of PVA/bentonite hybrid hydrogels were prepared by freezing/thawing method. For comparison, the PVA hydrogels by different numbers of cycles and with different loadings of bentonite were prepared. X-ray diffraction results show that the exfoliated structure exists in the hybrid hydrogels. For the PVA/bentonite (2.0%, w) hybrid hydrogel by 5 cycles, compared with the pure PVA hydrogels by 5 cycles (PVA5), the tensile modulus, tensile strength and strain at break are increased by 44.0%, 74.2% and 25.2%. Its swelling behavior is similar to that of PVA5. The tensile strength and strain at break of PVA/bentonite (0.5%, w) hydrogel by 5 cycles are higher than those of PVA5. Its final swelling ratio at 400 min is the biggest in all specimens.