天然纤维素/PVA复合水凝胶的形成机理及力学性能研究

Preparation and Mechanical Properties of Natural Cellulose/PVA Composite Hydrogels

为提高聚乙烯醇(PVA)水凝胶的力学性能,利用Na OH/尿素溶剂,通过物理交联循环冷冻-解冻法,制备了α-纤维素(α-CE)/PVA复合水凝胶。红外光谱,扫描电镜结果表明α-CE与PVA水凝胶基体形成互穿交联网状结构。研究发现α-CE与PVA分子链上的羟基间所形成的氢键使两者牢固结合。力学性能测试表明,复合水凝胶的力学性能得到了大幅度提高,当α-CE含量为4%(wt)时,复合水凝胶的拉伸强度以及在压缩型变量60%下的压缩应力分别由0.09和0.07 MPa提高到0.64和0.52 MPa,比纯PVA水凝胶提高了611%和643%。此外发现,α-CE能明显增强PVA水凝胶的弹性及压缩后的形变回复能力。

α-cellulose （α-CE） / poly（vinyl alcohol）（PVA） composite hydrogels were prepared via a repeated freezing and thawing method using NaOH/urea as a solvent to improve mechanical properties ofPVA hydrogels FT-IR and SEM results demonstrate that α-CE and PVA form a cross-linked network structure, which is tightly interconnected through hydrogen bond interaction between the two chemicals. This network structure can strongly enhance the mechanical properties of PVA hydrogels. The tensile strength of the α-CE/PVA composite hydrogels increased by 611% （from 0.09 MPa to 0.64 MPa） with 4%（wt） α-CE, and the compressive stress at 60% compressive deformation improved by 643% （from 0.07 MPa to 0.52 MPa）. In addition, α-CE is also beneficial to the elasticity of PVA hydrogels. The PVA hydrogels show better shape recovery with the incorporation of α-CE.