聚乙烯醇/蓝藻复合膜的制备及其结构与力学性能

Preparation,structure,and mechanical properties of PVAL/cyanobacteria composite films

针对太湖水华蓝藻(CB)资源化利用的问题,以生物可降解的聚乙烯醇(PVAL)为基体材料,CB粉末为填料,采用溶液混合、干燥成膜的方式,简便地制备了生物可降解的PVAL/CB复合膜。采用流变、扫描电子显微镜、力学性能测试等表征手段,研究了CB添加量对PVAL/CB水分散液的流变行为和失水动力学、PVAL/CB复合膜的形貌和力学性能的影响规律;以甘油(GL)为增塑剂,研究了GL对不同CB含量的PVAL/CB复合膜微观形貌和力学性能的影响规律。研究表明,CB添加量增加,会使PVAL/CB水分散液黏度略有升高,但对分散液成膜过程中的失水速率影响不大。对于PVAL/CB复合膜而言,CB添加质量分数为10%时,复合膜具有较为优异的综合力学性能,其拉伸强度和断裂伸长率可达(46.4±1.3) MPa和(112.1±8.8)%,但由于CB和PVAL基体界面结合牢度不足,添加过多的CB会引起复合膜脆性断裂,力学性能下降。对于PVAL/CB/GL复合膜而言,GL不仅能起到增塑作用,还能改善CB与PVAL基体间的相容性,提升界面结合牢度,从而提升PVAL/CB/GL复合膜的综合力学性能。高CB含量的PVAL/CB/GL复合膜未出现脆性断裂,30%CB含量的复合膜的拉伸强度和断裂伸长率仍可达(21.5±0.6) MPa和(261.2±13.6)%。PVAL/CB复合膜具有一定的生物可降解性,随CB含量增加,降解速率变快。

In view of the utilization of cyanobacteria(CB) in Taihu Lake,biodegradable poly(vinyl alcohol)(PVAL)/CB composite films were fabricated by using PVAL as the polymer matrix material and CB as the filler through a convenient solution blending and followed drying process.The effects of CB content on the rheological behavior and water evaporation kinetics of aqueous PVAL/CB dispersion,as well as the morphology and mechanical properties of PVAL/CB composite films were systematically investigated by the rheological test,scanning electron microscopy,and mechanical properties test.Besides,the effect of plasticizer,glycerol(GL),on the morphology and mechanical properties of PVAL/CB composite films with different CB contents was also studied.The results show that the viscosity of aqueous PVAL/CB dispersion is slightly increased with the increase of CB content.The water evaporation rate of aqueous PVAL/CB dispersion is hardly influenced by the CB content.For PVAL/CB composite films,the tensile strength and elongation at break of PVAL/CB composite film with 10% CB are(46.4 ± 1.3) MPa and(112.1 ±8.8)%,displaying superior comprehensive mechanical properties.However,due to the insufficient interfacial interaction between CB and PVAL matrix,addition of more CB would cause brittle fracture of the composite films,leading to the decrease of mechanical properties.For PVAL/CB/GL composite film,GL could not only play a plasticizing role,but also improve the compatibility between CB and PVAL matrix and the interfacial interaction,and thus improve the comprehensive mechanical properties of PVAL/CB/GL composite film.The PVAL/CB/GL composite films with high CB content do not undergo brittle fracture,and the tensile strength and elongation at break of the composite film with 30% CB content are(21.5 ± 0.6) MPa and(261.2 ± 13.6)%.The PVAL/CB composite films could undergo biodegradation,and the degradation rate could be accelerated with the increase of more CB.