Wang X L, Du F G, Jiao J, Meng Y Z, Li R K Y
State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Sun Yat-Sen University, Guangzhou 510275, People's Republic of China.
J Biomed Mater Res B Appl Biomater. 2007 Nov;83(2):373-9. doi: 10.1002/jbm.b.30806.
Biodegradable blends of poly(propylene carbonate)/ethylene-vinyl alcohol copolymers (PPC/EVOH) were melt prepared. The mechanical strength, crystallization and melting behavior, morphologies, and thermal properties of these blends were fully investigated using tensile tester, modulated differential scanning calorimetry, scanning electron microscopy, and thermogravimetric analysis, respectively. The results indicated that the thermal stability of blends could be enhanced by increasing EVOH content. No change was observed for the tensile strength when EVOH content was lower than 30 wt %. The tensile strength, however, increased obviously with increasing EVOH content when EVOH content was higher than 30 wt %. The crystallization behavior of the PPC/EVOH blends was studied accordingly. The degradability test showed that the weight loss of PPC/EVOH blends increased with increasing EVOH content because of the strong moisture sorption of EVOH. Morphology observation indicated that the PPC/EVOH blends exhibited a two-phase microstructure. The blends with EVOH contents ranging from 40 to 60 wt % showed the best comprehensive properties as biodegradable thermoplastic for many applications.
聚碳酸亚丙酯/乙烯-乙烯醇共聚物（PPC/EVOH）的可生物降解共混物通过熔融法制备。分别使用拉伸试验机、调制差示扫描量热法、扫描电子显微镜和热重分析对这些共混物的机械强度、结晶和熔融行为、形态以及热性能进行了全面研究。结果表明，通过增加EVOH含量可以提高共混物的热稳定性。当EVOH含量低于30 wt%时，拉伸强度未观察到变化。然而，当EVOH含量高于30 wt%时，拉伸强度随EVOH含量的增加而明显提高。据此研究了PPC/EVOH共混物的结晶行为。降解性测试表明，由于EVOH对水分的强吸附性，PPC/EVOH共混物的失重随EVOH含量的增加而增加。形态观察表明，PPC/EVOH共混物呈现两相微观结构。EVOH含量在40至60 wt%范围内的共混物作为可生物降解热塑性塑料在许多应用中表现出最佳的综合性能。
