Grevellec J, Marquié C, Ferry L, Crespy A, Vialettes V
Centre des matériaux de Grande Diffusion, Ecole des Mines Alès, 6 Avenue de Clavières, 30319 Alès Cédex, France.
Biomacromolecules. 2001 Winter;2(4):1104-9. doi: 10.1021/bm015525d.
The manufacture of biodegradable materials from agricultural sources is a real challenge, because of environmental concerns and the need to make full use of resources. Cottonseed is an important protein source that could be used in nonfood applications, as a substitute for synthetic polymers. For the first time, the viscoelastic behavior of cottonseed protein isolate (CPI), plasticized with glycerol, was characterized in order to determine the temperature range within which cottonseed protein-based materials can be formed by extrusion or thermomolding. Research involved three main techniques: dynamic mechanical analysis to study the alpha protein relaxation associated with glass transition, as a function of plasticization by glycerol; DSC analysis to determine the effect of glycerol content on the protein denaturation and degradation temperatures; and ATG-TG/FTIR to characterize the protein degradation. The results indicated that cottonseed proteins are thermoplastics with a T(g) ranging from 80 to 200 degrees C when the glycerol content varies from 0% to 40% (w/w, dry basis). The proteins' thermal denaturation temperature increased from 141 (without glycerol) to 195 degrees C in the presence of 40% (w/w) glycerol. Protein degradation occurred at 230 degrees C irrespective of glycerol content, with the release of a variety of compounds. Glycerol acts as a plasticizer and thermal stabilizer of the proteins and increases the range of temperatures (80-175 degrees C) at which the material can be processed.
出于环境方面的考虑以及充分利用资源的需求，利用农业资源制造可生物降解材料是一项实实在在的挑战。棉籽是一种重要的蛋白质来源，可用于非食品应用，以替代合成聚合物。首次对用甘油增塑的棉籽分离蛋白（CPI）的粘弹性行为进行了表征，以确定可通过挤出或热成型形成基于棉籽蛋白的材料的温度范围。研究涉及三种主要技术：动态力学分析，用于研究与玻璃化转变相关的α蛋白松弛，作为甘油增塑作用的函数；差示扫描量热法（DSC）分析，以确定甘油含量对蛋白质变性和降解温度的影响；以及热重-热重/傅里叶变换红外光谱（ATG-TG/FTIR）来表征蛋白质降解。结果表明，当甘油含量在0%至40%（w/w，干基）之间变化时，棉籽蛋白是热塑性塑料，其玻璃化转变温度（T(g)）在80至200摄氏度之间。在存在40%（w/w）甘油的情况下，蛋白质的热变性温度从141（无甘油时）升高到195摄氏度。无论甘油含量如何，蛋白质在230摄氏度时都会发生降解，并释放出多种化合物。甘油作为蛋白质的增塑剂和热稳定剂，增加了材料可加工的温度范围（80 - 175摄氏度）。
