Synthetic strategies of nanocellulose surface modification for functional bio-nanocomposites

为了开发更环保和更可持续的材料，需要从可再生原料中开发具有适当机械和功能特性的轻质结构材料(例如纳米复合材料)。纤维素纳米晶(CNCs)由于其可持续性、丰度、高比表面积和优异的力学性能，是开发此类材料的最有前途的候选材料之一。此外，它们的纳米结构和纳米尺寸使它们能够在分子水平上与聚合物相互作用，使它们成为合适的聚合物纳米膜。它们丰富的表面羟基可以被修饰以形成功能材料，如抗菌薄膜、刺激响应材料和疏水涂层。化学改性是一种有效的方法来调节数控表面适当的功能特性，控制它们在溶剂或聚合物基质中的分散，以及定制它们的界面和自组装特性，所有这些都有助于提高材料的性能。然而，对于碳纳米管在功能应用中的化学转化如何影响其纳米结构、结晶度、胶体性质以及由此产生的聚合物材料的物理化学性质，目前还知之甚少。这阻碍了它们在许多先进功能材料中的应用。*我们将对碳纳米管进行系统的化学剪裁，将其用作功能聚合物纳米复合材料的胶体支架，从长远来看，这将拓宽我们对碳纳米管及其在抗菌材料、防污表面、疏水和抗紫外线涂料等功能材料中的应用的科学认识。这项拟议的研究将通过专注于合成方法和加工技术来实现对纳米结构和功能的控制，从而扩大数控材料的应用。这些连接功能基团的基础研究，不仅为材料制备提供了一种新的方法，也为理解数控及其聚合物纳米复合材料的材料科学提供了一种新的方法。这项研究结合了聚合物化学和物理、过程工程和产品设计方面的科学挑战，因此将为HQP在不同级别提供有价值的多学科培训。总而言之，将培训一个由8名聚合物科学家和工程师组成的多学科团队(2名博士、2名硕士和5名本科生)。除了通过这些熟练的HQP提高加拿大的劳动力外，这项研究的成果还将通过创建一个新的增值可持续数控纳米材料出口市场而使加拿大经济受益，该市场有可能振兴加拿大的林业部门并提供环境效益，因为碳纳米材料的来源可持续地来自碳汇植物。*****

The quest to develop more eco-friendly and sustainable materials requires the development of lightweight structural materials (e.g. nanocomposites) with suitable mechanical and functional properties from renewable feedstock. Cellulose nanocrystals (CNCs) are among the most promising candidates for the development of such materials due to their sustainability, abundance, high surface area, and excellent mechanical properties. Additionally, their nanostructure and nano-size dimension allow them to interact with polymers at a molecular level, making them suitable polymer nanofillers. Their abundant surface hydroxyl groups can be modified to achieve the formation of functional materials, such as antimicrobial films, stimuli-responsive materials, and hydrophobic coatings. Chemical modification is an effective method to tune the appropriate functional properties on CNC surfaces, to control their dispersion in solvents or polymer matrices, and tailor their interfacial, self-assembling properties, all of which enable advances in material performance. However, there is little understanding about how chemical transformation of CNCs for functional applications may influence their nanostructure, crystallinity, colloidal properties, and the resulting physicochemical properties in polymer materials. This has hampered their utilization in many advanced functional materials. ***We will conduct systematic chemical tailoring of CNCs to utilize it as a colloidal scaffold for functional polymer nanocomposites, which will, in the long term, broaden our scientific understanding of CNCs and their utilization in functional materials such as antimicrobial materials, anti-fouling surfaces, hydrophobic and UV resistant coating. The proposed research will expand the application of CNC materials by enabling control over the nanostructure and functionality by focusing on synthetic approaches and process technologies. These fundamental studies of conjugating functional moieties onto CNC will provide both a new method for material preparation and an understanding of the materials science of CNC and its polymer nanocomposites. The research combines scientific challenges in polymer chemistry and physics, process engineering, and product design, and will, therefore, provide valuable multidisciplinary training for HQP at various levels. In all, a multidisciplinary team of 8 polymer scientists and engineers will be trained (2 PhD, 2 MSc, and 5 undergraduate co-op students). In addition to enhancing Canada's workforce with these skilled HQPs, outcomes of this research will benefit the Canadian economy by creating a new export market of value-added sustainable CNC nanomaterial that has the potential to rejuvenate Canada's forestry sector and provide environmental benefits, as CNCs are sustainably sourced from plants that are carbon sinks. *****