Fundamental understanding on nano-modifications of keratin biofibers for green biocomposites

越来越多的环境问题和社会对可持续产品的需求正在推动利用天然纤维作为每年生产的数百万吨合成纤维的部分替代品的研究。角质生物纤维，特别是家禽纤维，特别令人感兴趣，因为它们价格便宜，可再生，重量轻，可持续。作为食品工业的副产品，加拿大每年生产数百万磅的羽毛。这些纤维每年都是可再生的，商业上充足，质量稳定，供应有保证。然而，与这些纤维相关的许多技术挑战，如湿气敏感性、热加工过程中的气味释放以及加工后较差的热和机械性能。必须解决这些挑战，使这些材料在广泛的应用中得到应用，并与合成纤维竞争。一种避免这些缺点的新方法可以是在生物纤维中加入纳米结构来改善其性能。这项拟议研究计划的长期目标是了解和解决阻碍这些生物纤维在可再生生物复合材料中应用的挑战，以获得更高端和更高附加值的产品。其具体目标是开发有效的方法：(1)利用纳米结构，如多面体低聚倍半硅氧烷(POSS)纳米笼，通过常规和微波加热技术对天然角蛋白纤维(羽毛纤维)进行表面改性；(2)在不破坏肽键的情况下还原天然角蛋白生物纤维的二硫键，将纳米结构(POSS和纳米粘土)掺入还原的角蛋白中，通过挤压开发杂化生物纤维，并研究纳米颗粒对所得纤维性能的影响；(3)从整个羽毛再生纯角蛋白生物聚合物，优化再生条件，并对再生的角蛋白进行表征；(4)在溶液中对目标(3)再生的角蛋白进行纳米结构的改性，通过挤出法制备杂化生物纤维，考察纳米结构对热稳定性、耐湿性、易燃性、力学性能的影响，并与天然角蛋白和商业纤维进行比较。深入了解纳米结构对纤维宏观性能的影响，优化增强条件，将有助于发展性能更好的混杂纳米增强纤维。拟议研究的好处和结果对加拿大农业、家禽、天然纤维和复合材料/塑料行业具有非常重要的意义。这些纳米增强的天然纤维将减少我们对合成纤维的依赖，并刺激对其他天然纤维的纳米改性的进一步研究，以用于生物基材料的开发。拟议的研究计划将为高素质人才的培训提供独特的环境。

Increasing environmental concerns and demand by society for sustainable products is driving research on utilizing natural fibers as replacements for part of the several million tons of synthetic fibers produced annually. The keratinous biofibers, especially poultry fibers, are of particular interest because they are cheap, renewable, light weight, and sustainable. As a by-product of food industry, several million pounds of feathers are produced in Canada each year. These fibers are annually renewable, commercially abundant, of consistent quality, and have guaranteed supply. However, a number of technical challenges are associated with these fibers, such as moisture sensitivity, odor release during thermal processing, and poor thermal & mechanical properties after processing. These challenges must be addressed for these materials to be used in wide range of applications and to compete with synthetic fibers. A novel approach to circumvent these drawbacks can be the incorporation of nanostructures in biofibers to improve their performance. The long-term objectives of this proposed research program are to understand and address the challenges that hinder the applications of these biofibers in renewable biocomposites for higher end and more value-added products. The specific objectives are to develop efficient approaches for: (1) surface modification of natural keratin fibers (feather fiber) using nanostructures, such as polyhedral oligomeric silsesquioxanes (POSS) nanocages, both by conventional and microwave heating techniques; (2) reduction of disulfide bonds of native keratin biofiber without breaking the peptide linkage, incorporation of nanostructures (POSS and nanoclays) into the reduced keratin, developing hybrid biofiber by extrusion and investigation of the effects of nanoparticles on resultant fiber properties; (3) regeneration of pure keratin biopolymer from whole feather, optimize regeneration conditions, and characterize the regenerated keratin; and (4) modification of the regenerated keratin from Objective (3) in solution by nanostructures, preparation of hybrid biofiber by extrusion and investigate the effects of nanostructures on thermal stability, moisture resistance, flammability, mechanical properties, and compare with native keratin and commercial fibers. Gaining fundamental understanding of the influence of nanostructures on macroscopic properties of fibers and optimization of reinforcement conditions will result in the development of hybrid nano-reinforced fibers with improved performance. The benefits and outcomes of the proposed research are highly significant to the Canadian agriculture, poultry, natural fibers, and composite/plastic industries. These nano-reinforced natural fibers will reduce our dependency on synthetic fibers and stimulate additional research in nano-modifications of other natural fibers for biobased materials development. The proposed research program will provide a unique environment towards the training of highly qualified personnel.