壳聚糖/聚乙烯醇共混膜的氢键和相容性

Hydrogen-bonding and compatibility of chitosan/polyvinyl alcohol blend films

采用溶液共混法制备了不同配比的壳聚糖/聚乙烯醇共混膜,通过变温FTIR、TG、DTA、DSC及XRD等对共混膜的结构、氢键相互作用、热行为和结晶性等进行研究。实验结果表明,共混膜中壳聚糖与聚乙烯醇间存在强烈的氢键相互作用。氢键的存在使壳聚糖的热稳定性提高,聚乙烯醇结晶性下降,促进壳聚糖与聚乙烯醇相容。当壳聚糖/聚乙烯醇共混膜的质量比分别为10/0、7/3、5/5、3/7和0/10时,共混膜的初始分解温度分别为244℃、257℃、260℃、262℃和285℃。聚乙烯醇熔融温度从193℃下降到173℃,玻璃化转变温度从74.2℃上升至80℃,结晶度Xc从3.57%下降到1.97%。

Chitosan （CS） /polyvinyl alcohol （PVA） blend films with different compositions were prepared by solution casting technical using 2% acetic acid/water as a solvent. The structure, hydrogen-bonding, thermal behaviors and crystallization of CS/PVA blend films were systematically investigated by variable temperature FTIR, TGA, DTA, DSC and WXRD. It indicated that strong hydrogen-bonding interactions existed between CS and PVA, leading to the increase in thermal stability of CS, the decrease in crystallinity of PVA, and enhancement of the compatibility of CS and PVA. When the weight ratio ofCS / PVA blend films was 10/0, 7/3, 5/5, 3/7 and 0/10, the initial decomposition temperature of blends was 244 ℃, 257 ℃, 260 ℃, 262 ℃ and 285 ℃ correspondingly. The melting temperature of PVA was decreased from 193 ℃ to 173 ℃. The glass transition temperature was increased from 74.2 ℃ to 80 ℃, and the crystallinity Xc declined from 3.57% to 1.97%.