Some Thermal Properties of Fabrics

Abstract

Examination of the thermal conductivity of fabrics in terms of the fiber conductance and fabric density shows that fabric insulation is determined by fiber arrangement as well as by fabric thicknes. Fiber arrangement is interpreted in terms of fibers lying parallel and perpendicular to the fabric surface, and it is shown that fabrics differ appreciably in this respect. For the smooth surfaced fabrics of cotton, nylon, and Orlon studied, the in crease in specific conductivity with applied pressure can be attributed mainly to an in crease in fabric density as there is very little change in fiber arrangement in such fabrics. For fuzzy surfaced fabrics of wool or blends containing wool, the change in density with applied pressure is counterbalanced by changes in the fiber arrangement. At low pres sures a substantial portion of the fibers lie perpendicular to the fabric surface but are bent over as the pressure is increased. At high pressures the fibers lie mamly parallel to the surface, but the fabric conducts less effectively because of the air layers between each fiber along the conducting path. Accordingly the specific conductivity of wool and wool-type fabrics is relatively insensitive to changes in applied pressure and this appears to be a direct result of the random arrangement of the fibers in these fabrics.