Improved Mechanical Recycling of Cellulose Fibres and the Co-Production of Nanocellulose: A Biochemical Approach to Textile Waste Management

缩写：SEM：扫描电子显微镜X射线衍射NCC：纳米纤维素晶体摘要虽然合成纤维回收已经建立，但棉花的回收利用仍远远落后于预期的回收利用率[1]。机械回收可以帮助解决这个问题。然而，机械回收中的高摩擦作用缩短和降低了废纤维的质量，限制了该方法的使用(2)。因此，机械回收只能提供半封闭的解决方案，即将少量具有足够长度的废纤维与未加工纤维结合起来生产新纱线。为了在粉碎过程中保持废纤维的长度，从而增加合适的提取纤维的数量，必须减少摩擦力。这可以通过减少纺织品内部纱线间的摩擦，使其松动，从而降低撕裂力来实现。以前已经证明，环境友好的纤维素酶-酶处理可以降低织物的剪切刚性(3)，并通过降低碎纸力来辅助纸浆的精炼(4)。这些酶也被用于从棉花废料中生产高强度的NCC，然而，目前的方法存在产量低的问题(5)。本研究探讨了纤维素酶作为机械回收前处理的可行性，降低了机织棉织物的纱线间摩擦，并联合生产了可用作增强织物涂层的NCCs。这些处理通过减少纤维之间的接触点和松动结构来减少摩擦。关键词：机械回收、酶、纺织废料、纳米纤维素、纺织涂层、摩擦力研究问题：纤维素酶处理能否作为机械回收的前处理？研究目的：本项目旨在研究酶处理对机织棉织物机械粉碎过程中纱线间摩擦的影响。目的：1.优化酶处理工艺，降低纤维素基织物的梳合力和纱线间摩擦。从处理过的纺织品的机械粉碎中分离出长纤维。建立从反应溶液中提取酶产生的纳米纤维素晶体(NCC)的方法学。要求：学生将在实验室工作，用纤维素酶溶液处理以纤维素为基础的纺织品，例如棉花、Lyocell和/或粘胶。然后，将使用几种实验室技术，如X射线衍射和扫描电子显微镜，对纺织品进行表征，以了解酶处理对纺织品结构和形态的影响。剪切性能的变化也将通过力学试验来测量，例如倾斜拉伸试验和梳理试验。学生将在机械粉碎后测量处理过的纤维的长度，以评估处理在保持纤维长度方面的成功。新的工程学和/或物理学内容：将高价值的NCC产品整合到酶辅助的纺织废物的机械回收中。

Abbreviations: SEM: Scanning electron microscopyXRD: X-ray diffractionNCC: Nanocellulose crystalsAbstractWhilst synthetic fibre recycling has been established, the recycling of cotton is still far behind the expected recycling rates (1). Mechanical recycling can help to combat this issue. However, the high frictional actions in mechanical recycling which shorten and degrade the quality of waste fibres, places restrictions on the use of the method (2).Consequently, mechanical recycling can only offer semi-closed loop solutions whereby a small number of waste fibres, with adequate lengths, are combined with virgin fibres to produce new yarns. To maintain the lengths of waste fibres during shredding thereby increasing the number of suitable extracted fibres, the frictional forces must be reduced. This can be achieved by reducing inter-yarn friction within the textile, loosening it and therefore reducing the shredding force.Environmentally friendly cellulase-enzyme treatments have previously been shown to reduce the shear rigidity of fabrics (3) and assist in the refining of pulp by lowering the shredding force (4). These enzymes have also been used to produce high-strength NCCs from cotton waste, however, the current methodologies suffer from low yields (5). This study investigates the feasibility of cellulase as a pre-treatment to mechanical recycling, decreasing the inter-yarn friction of woven cotton fabric and co-producing NCCs that can be used as a reinforcing textile coating. The treatments reduce friction by reducing contact points between fibres and loosening the structure. Keywords: Mechanical recycling, enzymes, textile waste, Nanocellulose, Textile coating, frictional forcesResearch question: Can a cellulase enzyme treatment be used as a pre-treatment to mechanical recycling?Research aims: This project seeks to investigate the effect of enzyme treatments on the inter-yarn friction of woven cotton fabric during mechanical shredding.Objectives:1. To optimize the enzyme treatment to reduce the combing force and inter-yarn friction of cellulose-based textiles.2. To isolate long fibres from mechanical shredding of treated textiles.3. To produce a methodology to extract enzyme produced Nanocellulose crystals (NCCs) from the reaction solution.4. To coat cellulose fibres with enzyme derived NCC and quantify the mechanical properties.Approach: The student will be conducting laboratory work to treat cellulose-based textiles e.g., cotton, lyocell and/or viscose with a cellulase enzyme solution. The textiles will then be characterized using several laboratory techniques, such as XRD and SEM, to understand the effects of enzyme treatment on the structure and morphology of the textile. Changes in the shear properties will also be measured using mechanical tests such as bias extension tests and combing tests. The student will measure the lengths of treated fibres after mechanical shredding to assess the success of the treatments in maintaining fibre lengths.Novel engineering and/or physical sciences content: High-value NCC production integrated into enzyme-assisted mechanical recycling of textile waste.