完全醇解型PVA包装薄膜的耐水性研究

目的在保持聚乙烯醇(PVA)良好的水溶性、成膜性及生物降解性的基础上,提高聚乙烯醇薄膜的耐水性。方法采用完全醇解型PVA制备水溶性PVA包装薄膜,对薄膜进行化学交联处理、热处理,以及化学交联处理及热处理相结合等3种方式,研究其对薄膜结构和性能的影响。结果经饱和硼酸溶液化学交联处理后,PVA薄膜的吸湿率明显降低,大致可以确定硼酸浴液的最佳温度为70℃,最佳浸渍时间为5 min;经热处理后的PVA薄膜耐水性得到改善。结论经2种方式综合处理的PVA薄膜,既发生了化学交联又产生了结晶结构,其分子内亲水性羟基数量减少的同时,分子链的排列也更加规整有序,与单一处理方式相比,耐水性能得到较大改善。

Water Resistance of Complete Alcoholysis PVA Packaging Films

As an environmental polymer compound, polyvinyl alcohol (PVA) shows excellent water-solubility, film forming and biodegradability properties. But the production, promotion, and application of PVA film are largely restricted by its poor water resistance. This study aimed to improve the water resistance of PVA films. Complete alcoholysis type PVA1799 was used to prepare water-soluble PVA packaging film, and the effects of chemical cross-linking treatment, heat treatment, cross-linking treatment combined with heat treatment on the structure and performance of the film were studied. Analysis showed that the moisture absorption rate of PVA film decreased obviously after adding saturated boric acid solution. The basic optimal temperature of boric acid bath was 70 °C and the optimal immersion time was 5 minutes. The water resistance of PVA film was improved by heat treatment. Through two-way combined processing, not only the chemical cross-linking but also crystalline structure occurred in PVA film. The number of hydrophilic hydroxyl groups within the molecule reduced, and the molecular chain arrangement became more regular and orderly. Compared with the single processing mode, the waterproof performance was greatly improved.