A membrane is a thin layer of polymer on shell fabric of apparel. Beside waterproofing a membrane can increase the thermal protection of apparel by stopping irradiative heat loss.
We have modified a polyurethane membrane in two ways: addition of inorganic components and coating with different polymers. The addition of heat absorptive additives reduced heat transmittance of membrane from 85% to 3%. The presence of heat reflecting compounds decreased transmittance of PU film to 25%. Coating with polypyrrole revealed the highest decrease in heat transmittance (down to 1-3%) among all polymers. Both approaches made augmentation in clothing insulation when they were used in apparel.