Reducing the physiological burden of individual protective clothing with nanocellulose

1. 简介 目前用于个人防护装备 (IPE) 服装的技术为军事人员提供了针对 CBR 战剂的高水平防护。然而，穿着这种衣服的生理负担可能很高。一项主要挑战是去除身体热量，这可以通过使用透气织物来促进，因为这些织物可以使汗液中产生的水蒸气逸出防护服的微气候。然而，如果透气性太高，防护水平可能会显着下降。因此，人们对促进水蒸气从防护服中渗透而不妨碍防护水平感兴趣。受纳米纤维素的亲水性及其最近在增强非织造纤维和过滤方面的应用的启发，因此建议将纳米纤维素纳入开发一种减轻生理负担的轻型多功能IPE服装中。项目目标：微生物合成的纳米纤维素，例如该特定项目将采用细菌纤维素 (BC) 来生产纳米纤维素增强型 IPE 服装，其性能优于最先进的技术。主要目标是： 1．开发一种廉价、简单的制造工艺，具有与最先进技术相当的高透湿性和高尺寸排除效率的BC增强IPE服装；2．检查并优化BC的液体控制性能，提高IPE服装的拒水性；3．设计和优化包含 BC 的 IPE 服装的多层配置，以最大限度地提高防护效率。 2. 研究方法2.1． BC对IPE外衣面料的改性提出通过在外衣层的纱线上涂覆BC来提高IPE服装的过滤效率。 BC 对纺织纤维的天然亲和力使得 BC 可以附着在单根纺织纤维纱线上，也可以桥接多根纱线。据推测，BC无纺布会在织物结构内形成屏障，从而减少、过滤或消除有机分子或微粒的通过。将采用浆液浸渍法，将织物浸入BC悬浮液中并干燥，以生产BC涂层纱线。浸渍时间和 BC 水悬浮液的稠度都会发生变化，以研究和量化所得 BC 涂层的面密度。这些BC涂层织物将通过Gurley密度计来表征其透气性，并通过模型微粒和明确的粒径来表征过滤效率。扫描电子显微镜也可用于研究BC-纺织纱线界面和其他特性，例如颗粒过滤和接触角。 2.2.使用 BCIPE 服装定制和增强 IPE 服装的化学吸附能力通常由负载活性炭的内衬组成，通过吸附去除潜在的有害蒸气。然而，对该活性炭层的表面进行功能化以定制特定有害有机分子的吸附是具有挑战性的。相反，BC 具有广泛的化学改性能力，因此有机会为特定的有机分子吸附设计定制的表面特性。例如，有人建议用(2,2,6,6-四甲基哌啶-1-基)oxoxanyl (TEMPO)氧化BC，以便在BC表面引入羧基。 TEMPO 氧化 BC 已显示出亲水性，因此会吸收大量水分并进一步最大限度地去除身体热量。

1. Introduction The current technology used in individual protective equipment (IPE) apparel has provided a high level of protection against CBR warfare agents for military personnel. However, the physiological burden of wearing such clothing can be high. One major challenge is the removal of body heat, which could be facilitated by the use of air-permeable fabrics as these allow water vapour derived from sweat to escape the microclimate of the suit. However, if the air-permeability is too high the levels of protection can fall significantly. Hence, there is an interest in promoting the permeation of water vapour out of the suits without impeding the level of protection. Inspired by the hydrophilic nature of nanocellulose and their recent applications in enhancing nonwovens fibres and filtrations, it is thus proposed to incorporate nanocellulose in developing a light and multifunctional IPE costume with reduced physiological burden. Project aims:Microbially-synthesised nanocellulose, e.g. bacterial cellulose (BC), would be employed in this particular project to produce a nanocellulose-enhanced IPE garment with resulting performance improvements over the state-of-the-art. The key objectives are:1. To develop a cheap and simple manufacturing process BC-enhanced IPE garments with high moisture permeability and high size-exclusion efficiency comparable to the state-of-the-art;2. To examine and optimise the properties of BC for liquid control, increasing the repellence of the IPE garments;3. To design and optimise the multi-layer configuration of IPE garment incorporating BC to maximised protection efficiency. 2. Research methodology2.1. Modification of textile fabric in the exterior garment of IPE with BCIt is proposed to improve the filtration efficiency of the IPE clothing by coating the yarns of the exterior garment layer with BC. The natural affinity of BC to textile fibres would allow BC to attach either at a single textile fibre yarn level or to bridge across multiple yarns. It is hypothesized that BC nonwoven would form a barrier within the fabric structure so as to reduce, to filter or to eliminate the passage of organic molecules or micro-particles. Slurry dipping method, in which fabrics will be dipped into a BC suspension and dried, will be employed to produce BC-coated yarns. Both the dipping time and the consistency of BC-in-water suspension will be varied to investigate and quantify the areal density of the resultant BC coating. These BC coated fabrics would be characterised for their air permeability with Gurley densometer and filtration efficiency with model micro-particulates and well-defined particle diameter. Scanning electron microscopy might also be conducted to study the BC-textile yarn interface and other properties such as particulate filtration and contact angles. 2.2. Tailoring and enhancing the chemisorption capability of IPE garment with BCIPE garments often consist of activated carbon loaded inner lining to remove potentially hazardous vapours through adsorption. However, it is challenging to functionalise the surface of this activated carbon layer to tailor the adsorption of specific hazardous organic molecule. On the contrary, BC possesses a broad chemical modification capacity and has thus exhibited opportunities to design bespoke surface properties for specific organic molecules adsorption. For instance, it is proposed to oxidise BC with (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) in order to introduce carboxylic groups onto the BC surface. TEMPO-oxidised BC has shown to be hydrophilic and would therefore absorb significant amount of moisture and further maximise body heat removal.