FABRICATION OF POLYYURETHANE/NANOSILICA NANOFIBROUS MATS FOR WATERPROOF BREATHABLE FABRICS AND ASSESSING THE PERFORMANCE CHARACTERISTICS

Abstract

Polyurethane nanofibres were prepared by electrospinning technique using the solvent dimethylformamide. In this study the solution properties (viscosity and molecular weight) of Polyurethane and electrospinning process parameters were determined. Brookfield Viscometer and Ubbelohde capillary Viscometer is used to measure the viscosity of solution and molecular weight of polymer respectively. The results show that the viscosity of the polymer increases with increase in concentration of solution linearly. Solution viscosity increases with respect to time and decreases with respect to temperature. Molecular weight of Polyurethane is [M] = 6,231. This is in the range of fiber forming polymer. Electrospinning process parameters like concentration of solution, voltage and distance of electrospun nanofiber diameter have been investigated for Polyurethane nanofibrous mats. Fiber diameter and contact angle of water were investigated for development of waterproof breathable nanofibrous mat. After optimization of parameters Polyurethane / nanosilica based nanofibrous mats and two & three layered waterproof breathable fabrics were prepared and assessing the performance characteristics by using contact angle, water vapor transmission rate, air permeability and water wicking test methods. Morphology of the electrospun nanofibres was examined by the software image J, Contact angle test, water vapour transmission rate, air permeability and water wicking test was conducted to check the waterproofness and breathability of waterproof breathable fabrics. The nanofibre diameter increase with increase in concentration and voltage, but decrease with an increase in distance. And the contact angle of nanofibrous webs increases with decrease in diameter. The contact angle varies from 79±3 to 118±2 for Fabrication of Polyurethane/ Nanosilica Nanofibrous Waterproof Breathable Fabrics and Assessing the Performance Characteristics Department of Applied Chemistry, DTU, Delhi Page 6 various Polyurethane nanofibrous mats. Polyurethane / nanosilica nanofibers were successfully obtained with maximum contact angle 138±1. In waterproof breathable fabrics, polyester fabric has high waterproofness and breathability than cotton. Silica nanoparticles improve the waterproofness and breathability both in two layer, PU + nanosilica deposited cotton (CS) fabric and three layer, PU + nanosilica deposited on cotton + polyester (CPS) fabric. Polyurethane nanofibrous cotton (CU) fabric has lower waterproofness and breathability.