Moisture barrier layer with supplemental chemical and biological protective functionality for firefighting clothing applications

One of the primary constituent layers of fire protective clothing is a flame-retardant, waterproof and breathable moisture barrier, which permits the outward transfer of perspiration from the firefighter’s body, while barring the inward entry of water. The introduction of a chemical and biological resistant functionality can greatly enhance the overall applicability of fire protective clothing. In the present work, a chemical & biological resistant waterproof breathable flame retardant moisture barrier fabric was prepared by laminating a biaxially stretched microporous expanded polytetraflouroethylene (ePTFE) membrane with Activated Carbon Fabric using a hot melt reactive breathable polyurethane adhesive. The developed laminate was found to exhibit an excellent balance of waterproofness (23 kPa) and breathability, which was quantified in terms of water vapour transmission rate (WVTR) and water vapour resistance (R _et ). High values of WVTR, 1.1025 × 10 ⁴ ± 9.8×10 ¹ g/m ² /day complimented with exceptionally low values of R _et, 2.9 m ² Pa/W are indicative of its high degree of breathability. Vertical flammability tests clearly revealed the exceptional flame resistance offered by the laminate, where after-flame, after-glow or melt-dripping was not observed and the char length was ∼4.2 cm. Further, the laminate exhibited requisite degree of protection against biological and chemical warfare (CW) agent with no breakthrough of the CW agent being perceived within the time frame of 24 h. The excellent combination of flame retardancy, breathability, waterproofness, chemical and biological protection, bestows the laminate excellent potential for usage as moisture barrier in fire protective clothing applications.