Testing of polyvinyl alcohol and starch mixtures as biodegradable polymeric materials

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• 作者：Tudorachi ; N. ; Cascaval ; C.N. ; Rusu ; M. ; Pruteanu ; M.
• 刊名：Polymer Testing
• 出版年：2000
• 出版时间：August, 2000
• 年：2000
• 卷：19
• 期：7
• 页码：785-799
• 全文大小：803 K

文摘

The mechanical properties, thermal behaviour and biodegradation of some polymeric materials based on polyvinyl alcohol and starch, in the presence of urea (used as a micro-organism nitrogen source/plasticizer) and glycerine (used as a plasticizer) have been studied. The chemical composition optimization of the analysed blends was carried out using a second order factorial experimental design. The progress of biodegradation was evidenced by means of scanning electronic microscopy, differential scanning calorimetry and thermogravimetric measurements. The evaluation of the weight loss of the samples at the end of the biodegradation process was also carried out. The weight loss after 18 days of inoculation with microorganisms is between 38 and 73 % by weight and is influenced by the composition of the blend as well as by the nature of the microorganism used. During biodegradation, plasticisers (glycerine and urea) and starch are consumed together with some amorphous structures from polyvinyl alcohol. The crystalline structures of polyvinyl alcohol which remained after biodegradation show high values of entalpy, and contribute to an increase in the apparent thermal stability of the biodegraded samples.