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

日益增长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。角化生物纤维，特别是家禽纤维，由于其廉价、可再生、重量轻和可持续发展而受到特别关注。作为食品工业的副产品，加拿大每年生产数百万磅的羽毛。这些纤维每年可再生，商业上很丰富，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，例如湿气敏感性，热加工过程中的气味释放，以及加工后的热机械性能差。这些挑战必须得到解决，这些材料用于广泛的应用，并与合成纤维竞争。克服这些缺点的一种新方法是在生物纤维中加入纳米结构以提高其性能。这项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，以用于更高端的和更高附加值的产品。具体目标是开发有效的方法：(1)利用纳米结构，如多面体低聚硅氧烷（POSS）纳米笼，通过传统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)在不破坏肽链的情况下还原天然角蛋白生物纤维的二硫键，在还原的角蛋白中加入纳米结构（POSS和纳米粘土），通过挤压形成杂交生物纤维，并研究纳米颗粒对合成纤维性能的影响；(3)利用全羽毛再生纯角蛋白生物聚合物，优化再生条件，对再生的角蛋白进行表征；(4)利用纳米结构对目标(3)再生的角蛋白在溶液中进行改性，通过挤出法制备混杂生物纤维，研究纳米结构对热稳定性、防潮性、可燃性、力学性能的影响，并与天然角蛋白和商用纤维进行比较。深入了解纳米结构对纤维宏观性能的影响，优化增强条件，将有助于开发出性能更高的纳米混杂增强纤维。拟议研究的收益和结果对加拿大农业、家禽、天然纤维和复合/塑料工业具有重要意义。这些纳米增强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。拟议的研究方案将为培养高素质人才提供独特的环境。

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.