淀粉基生物可降解材料的研究新进展

Recent Progress on Starch-based Biodegradable Materials

从淀粉的微观结构、加工过程中的相变及淀粉改性等基础理论出发,针对淀粉基材料存在的机械性能较低,对水敏感性高等缺陷,以及发泡材料制备的特点,介绍了最新的基础研究和应用研究成果.本文从淀粉基全天然高分子复合材料、纳米复合材料、自增强复合材料及功能性复合材料四个方面介绍了通过共混与复合制备淀粉基可生物降解材料,并且介绍了淀粉基材料防水改性的相关进展.指出使用可再生的天然高分子材料对淀粉进行改性,不仅能够提高材料的各种性能,而且由于所有组分都来源于天然材料,制备出的共混、复合和涂层材料也都环保安全,甚至可以用来制备可食用包装,为研制新型淀粉基材料提供有力的理论和技术支持.另外,目前对水在淀粉基发泡材料中如何同时担任增塑剂和发泡剂的机理研究取得突破性进展,发现并控制了泡孔结构由闭孔到开孔的转换临界点,研制并产业化了全淀粉发泡材料.基于上述讨论,指出淀粉基可生物降解材料既有机遇,同时也面临挑战.

Starch-based materials have showed greatly potentials,especially when more and more countries have passed the standards or regulations of banning or restricting disposable plastics.Many products,such as films,capsules,sheets,foam etc.,have been developed and commercialized.Like all other materials,improving performance and decreasing cost are two on-going strategic.In principle,the properties of starch-based materials can be significantly improved by blending with synthetic oil-based polymers.However,these blends were not biodegradable thus losing the advantage of using a biodegradable polysaccharide.The polymer blends and composites only from natural raw materials are discussed in this work.This paper reviews the recent development of starch-based biodegradable materials.Based on fundamental achievements,such as microstructures,phase transitions and starch modified,this paper mainly focused on the latest development of solving some wellrecognized weakness,such as lower mechanical properties,moisture sensitivity and developing starch-based foaming materials.It was found that various technologies in polymer industrials,such as blending,compositing,grafting,crosslinking,coating etc.,have been successfully developed to improve the performance of starch-based materials.The progress of starch-based polymer blending and compositing were introduced from four parts,including natural polymer composites,nano-composites,self-reinforce composites and functionalized composites,as well as the progress of starch waterproofing modification.It has been noticed that application of the natural materials from renewable resources as reinforce agents can not only reinforce or improve the performance of starch-based materials,but also develop environmentally friendly,even edible packaging.It is pointed out that application of the natural materials from renewable resources to reinforce or improve the performance of starchbased materials has showed great potential.It provides powerful theoretical and technical support for the development of new starch-based materials.Furthermore,through investigating the effects of water content on melting temperature(Tm),crystallinity,foaming process,cell structures well as mechanical properties,the mechanism of how water acting as both plasticizer and blow agent at the same time have been explored.It was found that there existed a critical point of water content(between 16%–18%)at which the expending ratio changed significantly since the cell structure changed from opening to closing.These starch-based foaming materials were developed and industrialized.In summary,there are both challenges and opportunities in developing starch-based materials.