Superabsorbent polymer and silica aerogel incorporated textiles for chemical protection and thermal comfort

Chemical protective clothing (CPC) refers to apparel or fabric-related items designed to safeguard the wearer from hazardous chemicals. This clothing system is considered the last line of defence in any chemical-handling operation, and the key requirements of such clothing are to provide reliable protection with a minimal negative effect on the comfort of the wearer. However, the achievement of two contradictory goals, maximum protection with an acceptable level of comfort, is the main challenge in developing CPC, and thus, unremitting research efforts are enduring globally in investigating innovative materials, methods, and practices to accomplish these two opposing aspects in the clothing system. Hence, this study aims to develop a novel CPC that can resist the penetration of water and liquid chemicals and have breathability for thermal comfort. To accomplish the key objective of the research, the fabrication of protective clothing was accompanied by using porous silica aerogel particles and hydrophilic superabsorbent polymers (SAP).

Sodium polyacrylate as an SAP was incorporated in CPC to increase the moisture vapour transmission for thermophysiological wear comfort. The impermeable polymeric coating of polyurethane (PU) and SAP on the cotton fabric showed effective resistance against the penetration of water and liquid chemicals through the fabric. The embedding of SAP in the coating has improved the evaporative transmittance by employing its hydrophilic nature that conferred much greater thermal comfort to the user. Besides, the padding of PU-SAP coating with fluoropolymers developed an omniphobic surface that has the repellency against water, oils, and aqueous solutions with very low surface tension as well as retaining high permeability to perspiration vapour.

Lightweight porous silica aerogel was integrated into chemical barrier clothing to provide simultaneous liquid chemical protection and thermal comfort. The protective coating on cotton fabric by incorporating silica aerogel with PU resists the penetration of water and certain liquid chemicals through adsorption into the porous aerogel structure. The porous PU-aerogel coating demonstrated a high thermal resistance and permeability to air and moisture vapour. Besides, novel protective interlining developed by embedding silica aerogel particles with viscose nonwoven fabrics exhibits simultaneous protection against heat and liquid chemical penetration. The aerogel-nonwoven protective fabric also demonstrated sufficient breathability with improved evaporative transmittance and moisture permeability index, suggesting that the fabrics could create a favourable thermal comfort microenvironment between the skin and clothing. Furthermore, lightweight flexible clothing with versatile protective performance was fabricated by sandwiching a polyacrylinitrile-silica aerogel nanofibrous membrane into the viscose nonwoven fabric. The nonwoven substrate embedded with the functionalised nanofibre membrane shows satisfactory resistance against radiant heat and liquid chemical penetration. Adequate breathability was also observed for the newly developed fabric due to high air permeability and sufficient moisture vapour transmission.

This research shows an innovative application of silica aerogel and superabsorbent polymers for the fabrication of breathable protective clothing that can resist the water and liquid chemical penetration. The newly developed CPC has demonstrated a synchronised protective performance and comfort for the wearer. Accordingly, the key objective of the research has been fulfilled satisfactorily through achieving the protection and thermal comfort in the barrier clothing system.