Optically Active Polyurethane/Silica Aerogel Coated Cotton Fabrics for Thermal Protection

Ling Lin,Ziyin Li,Wenyao Li,Chaoxia Wang,Haiyan Mao

doi:10.3389/fmats.2021.681678

Abstract

Application of SiO2 aerogel in thermal protective clothing has been limited due to its brittle nature, ordinary mechanical properties, and poor film forming performance. This work is aimed to develop thermal protective cotton fabrics by coating blended OPU/SiO2 aerogel with enhanced mechanical properties and thermal protection performance. The OPU/SiO2 aerogel composites with different ratio were applied onto cotton fabrics by knife-coating. The morphology, chemical component, crystalline structure, thermal stability and compression strength were characterized by scanning electron microscopy (SEM), Fourier transfer Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG) and compression test, respectively. Besides, the warmth retention performance and heat protection performance together with air and moisture permeability of the coated fabrics were studied. The results showed that OPU/SiO2 aerogel were successfully coated onto cotton fabrics with enhanced mechanical properties and thermal stability together with better film forming capacity. The heat transfer coefficient of the coated cotton fabrics was distinctly dropped due to the synergistic effect of OPU and SiO2 aerogel, which resulted in higher warmth retention. The OPU/SiO2 aerogel coated fabrics exhibited obvious heat insulation performance with its surface temperate almost 4°C than the uncoated fabrics. This work demonstrates a new strategy of fabricating stronger thermal insulating textiles using OPU/SiO2 aerogel composites.

Highlights

Thermal protective clothing is essential for wearers who are subject to threats from environments such as extremely cold weather, special low temperature industrial environment and/or geometrically challenging locations
The optically active polyurethane (OPU)/SiO2 aerogel coating layer was formed on the surface of cotton fabric with the knife
The organic/inorganic blending of OPU and SiO2 aerogel has greatly enhanced the mechanical properties and membrane forming of the coated layer on cotton fabrics

Summary

Introduction

Thermal protective clothing is essential for wearers who are subject to threats from environments such as extremely cold weather, special low temperature industrial environment and/or geometrically challenging locations (e.g., the polar region of the earth; Kothari and Chakraborty, 2016; Udayraj et al, 2016a,b; Bogerd et al, 2017; Su et al, 2020). Heat is generally transferred via thermal conduction, thermal radiation and thermal convection (Abbasi et al, 2016; Hayat et al, 2016; Dai et al, 2018; Ge et al, 2019). The clothing system serves as the barrier between environment and human body, in which the fibrous materials and fibrous structure dominate the heat transfer from body to environment. Conventional thermal protective clothing is based on thermal insulating fibers, e.g., down fiber, with highly porous structure in the clothing system (Shu et al, 2017). These thermal protective products are functionally competent for daily wearing such as winter coat. There is a big challenge in protecting human from extreme environmental conditions, as under extreme environmental conditions the traditional

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