Researchers report a simple method to convert food waste into cellulose-based plastics of varying thermal and mechanical properties (Macromolecules 2014, DOI: 10.1021/ma5008557).

Most synthetic plastics have environmental concerns: They’re petroleum-based; they can’t biodegrade; or they potentially contain toxic compounds such as phthalates. Ilker S. Bayer, Athanassia Athanassiou, and their colleagues at the Italian Institute of Technology have sought ways to make plastics from biomass so that the materials are renewable, biodegradable, and possibly less toxic. One potential feedstock is cellulose, which, as a component of plant cell walls, is nature’s most abundant renewable polymer.

In their new plastic-making method, the researchers turned to a technique that’s normally used to break down cellulose into simpler sugars for biofuel production: soaking the material in acid. Because the researchers only wanted to break apart the cellulose’s crystalline structure—and not convert it into simple sugars—the team used trifluoroacetic acid (TFA), which isn’t as strong as acids used in biofuel applications.

The team used TFA to soak inedible waste from four food crops: spinach, rice, cocoa beans, and parsley. After several days of soaking, the researchers removed the volatile acid, yielding plastic coatings and films with a variety of mechanical properties. These materials have tensile strengths similar to synthetic polymers such as polyethylene terephthalate and polyethylene, the researchers say. The plant-waste plastics start to thermally degrade at temperatures between 150 and 300 ºC, which is similar to the range for synthetic polymers.

参考译文：
农产品加工过程中会产生大量不适合食用的废料，例如米糠、果壳、绿叶类蔬菜难以食用的茎等等。这些废料的主要成分是纤维素，这是一种有着良好机械性能的天然高分子，在许多场合可以代替人工合成的塑料。但是，植物中的纤维素通常以晶体的形式存在，加工比较困难。

来自意大利的研究人员近日发现，只要将这些废料浸泡在一种常见的有机酸——三氟乙酸中，废料中的纤维素的晶体形态就会逐渐被破坏，纤维素得以溶解在三氟乙酸中，便于进一步的加工。利用这种方法，研究人员成功将多种农产品加工过程中产生的废料转化为塑料，其机械强度、热稳定性等性能均可以媲美常见的合成塑料，而且废弃后可以在微生物的作用下逐渐降解。这项研究提供了以可再生的生物资源为原料生产塑料的一种新方法，有助于减轻塑料制品的生产对于化石能源的依赖以及对环境的破坏。

原始来源：http://cen.acs.org/articles/92/web/2014/07/Simple-Acid-Soak-Turns-Food.html