Optimization of Thermal Conductivity of Handloom Woven Silk–Cotton Union Fabrics using Response Surface Methodology

Thermal conductivity is a key determinant of thermos-physiological comfort in apparel textiles, governing the rate of
heat transfer between the human body and the external environment. Although pure silk (silk-by-silk) fabrics are widely
appreciated for their lusture, drape, and smooth handle, previous studies report relatively higher thermal conductivity
due to the compact filament structure and reduced air entrapment, which may limit insulation performance under
variable climatic conditions. Earlier investigations have concentrated on mechanized woven systems or single-fiber
constructions, with limited systematic optimization of handloom-woven silk–cotton union fabrics using statistical
design approaches. Addressing this research gap, the present study employed Response Surface Methodology based on
a Box–Behnken Design to optimize thermal conductivity by varying weft yarn count (20–40 Ne), twist per inch (10–20
TPI), and picks per inch (55–65 PPI), while maintaining constant silk warp parameters. Thermal conductivity ranged
from 0.0014 to 0.0020 W/m·K, with pick density showing the most significant influence; the minimum value (≈0.0014
W/m·K) was achieved at moderate yarn fineness, controlled twist, and higher pick density. Compared with silk-by-silk
fabrics, the optimized union fabrics exhibited lower thermal conductivity due to enhanced air entrapment from cotton
weft yarns. The study demonstrates the potential of statistically engineered handloom fabrics for sustainable, climateresponsive apparel, with future prospects in smart textile integration and performance-oriented garment design