【作者】 兰俊杰；

【导师】 马莺；

【作者基本信息】 哈尔滨工业大学 ， 生物化工， 2007， 硕士

【摘要】 近年来,由于塑料垃圾造成的环境污染问题和石油危机给塑料工业带来的巨大压力,使得对可降解塑料的开发成为各国竞相研究的热点领域。淀粉具有来源广泛、价格低廉、可再生、可生物降解等优点,已公认为是最具有发展潜力的生物降解塑料的原料而被广泛研究。本文以高直链玉米淀粉为主要原料,采用流延法通过共混、增塑、交联等工艺过程制备淀粉基可降解膜,研究了直链淀粉含量、增塑剂、交联剂、淀粉/聚乙烯醇(PVA)配比以及成膜介质、反应温度、搅拌速度等因素对高直链淀粉基可降解膜的影响。以PVA40%、甘油20%、乙二醛10%、尿素2%为最佳助剂用量,在以有机玻璃板为成膜介质、反应温度90℃、交联反应pH值2、搅拌速度120 r /min、烘干温度70℃的最佳工艺条件下制备高直链淀粉基可降解膜:拉伸强度32.8MPa、断裂伸长率135%、透光率42.1%、吸水率41.7%和吸油率0%,其性能明显高于普通淀粉基可降解膜。采用FTIR、XRD、DSC和SEM对淀粉基可降解膜进行表征和微观结构观察。证明了乙二醛的交联反应和甘油的增塑作用;高直链淀粉基薄膜由于两相相容性好因而热稳定性高于普通淀粉基薄膜;薄膜断面的扫描电镜照片显示,高直链淀粉基薄膜内部结构比普通淀粉基薄膜更致密。采用土埋法对淀粉基薄膜进行降解性实验,以失重率为评价指标,并使用扫描电镜对膜表面进行微观结构观察。实验发现,不同直链淀粉含量的薄膜其降解形式具有差异性,并初步探讨了原因。高直链淀粉基薄膜降解50d后失重率可达68%以上,具有良好的生物降解性能。更多还原

【Abstract】 Since the development of plastics earlier this century, it has become a popular material used in a wide variety of ways. But now, plastics become a huge pollution problem in the world. Biodegradable plastics made with plant-based materials have been available for many years. Starch is a natural polymer. Because of its cheapness and regeneration, it has been recognized as a kind of potential raw material for producing biodegradable plastics.In this paper, based on amylose having better filming properties than native corn starch, the starch-based degradable film with higher amylose content was produced by chemical cross-linking. The optimal additives content and producing conditions are as following: polyvinyl alcohol (PVA), 40%; glycerol, 20%; glyoxal, 10%; urea, 2%; the reaction temperature, 90℃;cross–linking reaction pH, 2; stirring speed, 120r/min; and drying temperature, 70℃. The produced film’s tensile strength, elongation at break, transmittance, water absorption and oil absorption were 32.8MPa, 135%, 42.1%, 41.7% and 0%, respectively. The films produced by native corn starch and corn starch of higher amylose content (82%) were characterized by FTIR and XRD. The spectrum proved that the chemical reaction took place between glyoxal and hydroxy. Thermodynamic properties of the films were analyzed by DSC, and the result showed corn starch of higher amylose content (82%) based film has better stability compared to native corn starch based film. The SEM photograph of film cross section displayed the structure of corn starch of higher amylose content (82%) based film was more compact than native corn starch based film. Starch based films were buried in soil in order to evaluate their degradability. The corn starch of higher amylose content (82%) based film has been decomposed 68.2% after 50 days. The SEM photograph of film revealed that amylose content affected the degradability of starch based film, and the preliminary explanation of this phenomenon was given.更多还原