Recent Advances in Breathable Barrier Membranes for Individual Protective Equipment

Stuart      A. Brewer

Abstract

This review covers patents that have been published recently on materials that can be incorporated into garments to provide protection from toxic chemicals. Toxic chemicals are defined as substances that can either kill or seriously incapacitate people due to the physiological effects that they have. The review specifically concentrates on semipermeable membranes i.e. those that will act as a barrier to toxic materials but are permeable to water vapour. These breathable membranes offer a lower physiological burden than completely impermeable barrier films since they will allow for significant amounts of water vapour to escape through the protective clothing. These membranes, that in this review are defined as those that possess water vapour permeabilities in excess of 400g m-2 day-1, can be divided into porous and non-porous (hydrophilic) systems. In addition, recent advances in responsive (adaptive) membranes that can switch between permeable and non-permeable modes are also discussed.

Keywords: Breathable membranes, protective clothing, protective materials, water vapour permeable, chemical barrier, CBRN clothing, Toxic chemicals, physiological effects, Sarin (GB), Soman (GD), Lewisite, Sulphur Mustard, respiratory protection, dermal protection, permeable, impermeable, fluoropolymer coatings, fibrous filtration media, activated carbon, Joint Service Lightweight Integrated Suit Technology (JSLIST), neoprene, butyl rubber, fluoroelastomers (e.g. Viton™), polyvinyl chloride, water vapour permeability, POROUS MEMBRANES, porous polymeric membrane, microporous polyure-thanes, Viton™, Teflon™, aqueous-borne contaminants, contact angle, water-based biological fluids, fluorocarbon, telomeri-sation, perfluoroalcohols, surface tension, oleophobic, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene, ethylene/vinyl acetate (EVA), PVA (polyvinyl alcohol), polyurethane coating, polyimide Lenzing P78 (a polymer, isopropyl alcohol, MONOLITHIC HYDROPHILIC BARRIER, permeability, solubility, diffusivity, fluorinated ion-exchange polymer, POLYAMINE CONTAINING BARRIERS, chemical warfare agents, nerve agents, neutralising agent, polyolefins, carbamic acid, crustaceans, Chitosan film, sulphonated polymer, sulphonated polyether sulphones (sPES), sulphonated polyetheretherketones, (sPEEK), fluorinated polybutadiene, lyophilic liquid crystal (LLC), butyl rubber (BR), polymer electrolyte membrane (PEM), Perfluorosulphonic acids (PFSA, sulphonic acid, chlorotrifluoro-ethylene, (polychlorotrifluoroethylene, PCTFE), non-breathable film, breathability, elastomer, polyolefinic thermoplastic, polybutyleneterphthalate, PBT, abrasion resistance, water soluble surfactant, non-woven membrane, detoxifying effect, oxime-modified magnetite particles, organo-phosphate nerve agents, ADAPTIVE MEMBRANES, (RESPONSIVE MEMBRANES), macroscopic properties, chemical sensors, filtration, controlled drug release, mechanical punching, laser, electron beam drilling, applied electrical field, poly-(2-acryl-amido-2-methyl propane sulphonic acid), diphenylmethane 4,4-bismaleimide (BMI)-co-PAMPS, poly(methylacrylic acid) (PMAA), poly(acrylic acid) (PAA), oxygen plasma, grafting, nerve agent Sarin (GB), Joint Service Lightweight Suit Technology (JSLIST), physiological burden, evaporative cooling, chemical hazards, heat exchangers