Bulletin of
Vitebsk State
Technological
University

Abstract

Currently, when designing thermal protective clothing, complex membrane materials are used. However, the processes of heat transfer, absorption and release of moisture within these materials remain poorly understood. One of the scientific problems is the identification of factors influencing changes in the thermal resistance of clothing materials, as well as the assessment of the significance and vector of impact of this influence on a person’s feeling of comfort in clothing.

The aim of the work is to determine the factors that most significantly influence the thermal resistance of complex membrane materials for clothing under humid conditions, and to assess the significance of this influence for the rational selection of materials for a package of demi-season clothing.

The study applied author's and standard methods and tools to study the structure, hygroscopicity, and thermal resistance of materials. The subjects of the study were three-layer composite materials consisting of woven and knitted fabrics bonded with an adhesive membrane sandwiched between them.

It has been established that the thermal resistance of materials is significantly affected by their hygroscopicity, membrane type, and wetting time. The effect of material thickness is detectable up to a certain wetting value of the samples. The study's results are summarized in the form of recommendations for the use of materials with specific structures in the production of demi-season clothing. It is shown that materials with a hydrophilic membrane are not suitable for use in demi-season clothing. Under humid conditions, their thermal resistance changes according to a complex law, decreasing and increasing within the range of (±10) %, therefore it more likely results in wearer discomfort.

The thermal resistance of materials with a porous hydrophobic membrane decreases uniformly when moistened within 5 % of the initial value, which makes these materials suitable for designing demi-season multi-purpose clothing.

Thermal protection properties of complex membrane materials under humidification