Synthesis of poly(N-isopropylacrylamide) polymer for fabrication of thermo-responsive cotton fabric

385-397Thermo-responsive poly (N-isopropylacrylamide) (PNIPAM) polymer has been synthesized by free radical addition polymerization method. The chemical structure of the synthesized polymer has been clarified by FTIR spectroscopy and 1 H NMR analyses. Turbidity test shows that the synthesized polymer exhibits thermo-responsive properties, depending on change in temperature. Its lower critical solution temperature (LCST) value is measured as 31°C by DSC analysis. The PNIPAM polymer is then applied onto the cotton fabric in two different concentrations using double-bath impregnation method. Change in hydrophilic character of the fabric, which is temperature dependent, has been revealed by drop and absorption capacity tests, contact angle measurement and surface energy calculation. The test results show that the fabrics exhibit thermoresponsive behavior. Their hydrophilic character is turned to the hydrophobic character above LCST of the polymer. The water vapor permeability of the polymer treated fabrics at temperatures above LCST increases as compared to the untreated fabric due to the increase in fabric porosity. Below LCST, water vapor permeability is increased because of the increasing hydrophility. Consequently, it is concluded that the water vapor permeability of the fabrics can be controlled by changing the temperaturedependent hydrophilic/hydrophobic characteristic and porosity, resulting from swelling or shrinkage of the polymer molecules

Synthesis of poly(N-isopropylacrylamide) polymer for fabrication of thermo-responsive cotton fabric

Thermo-responsive poly (N-isopropylacrylamide) (PNIPAM) polymer has been synthesized by free radical addition polymerization method. The chemical structure of the synthesized polymer has been clarified by FTIR spectroscopy and 1H NMR analyses. Turbidity test shows that the synthesized polymer exhibits thermo-responsive properties, depending on change in temperature. Its lower critical solution temperature (LCST) value is measured as 31°C by DSC analysis. The PNIPAM polymer is then applied onto the cotton fabric in two different concentrations using double-bath impregnation method. Change in hydrophilic character of the fabric, which is temperature dependent, has been revealed by drop and absorption capacity tests, contact angle measurement and surface energy calculation. The test results show that the fabrics exhibit thermo-responsive behavior. Their hydrophilic character is turned to the hydrophobic character above LCST of the polymer. The water vapor permeability of the polymer treated fabrics at temperatures above LCST increases as compared to the untreated fabric due to the increase in fabric porosity. Below LCST, water vapor permeability is increased because of the increasing hydrophility. Consequently, it is concluded that the water vapor permeability of the fabrics can be controlled by changing the temperature-dependent hydrophilic/hydrophobic characteristic and porosity, resulting from swelling or shrinkage of the polymer molecules

Fabrication of thermoresponsive cotton graft PNIPAA fabric

The aim of this study is to produce thermoresponsive cotton fabric. For this aim, poly(N-isopropylacrylamide) (PNIPAA) polymer was synthesized and grafted on the cotton fabric by free radical polymerization method. PNIPAA-grafted cotton fabric (PNIPAA-g-CF) was characterized chemically and morphologically and tested to investigate thermoresponsive property. Morphology and chemical structure of PNIPAA-g-CF were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectrophotometer analysis, respectively. The results of this study indicated that PNIPAA polymer synthesis and coating on to the cotton fabric surface was realized successfully. Thermoresponsive behaviour of PNIPAA-g-CF was determined by optical microscopy (OM) analysis, and wetting time, water uptake, water vapour permeability and contact angle measurements were performed at different temperature. The results indicated that hydrophilic characteristic of the fabric changed to the hydrophobic depending on increasing temperature. Besides, the pores of the fabric were getting bigger with increasing temperature. All results showed that the PNIPAA-g-CF exhibited thermoresponsive behaviour. © 2018, © 2018 The Textile Institute.4486-D2-16This work was financially supported by the Suleyman Demirel University (Project No. 4486-D2-16)

Development of thermo-regulating fabrics using PCM microcapsules with poly(methyl methacrylate-co-2-hydroxy ethyl methacrylate) shell and n-alkane core

Purpose: The purpose of this paper is to prepare microencapsulated phase change materials (PCMs) and apply them to cotton and wool fabrics for developing thermo-regulating fabrics. Design/methodology/approach: Microencapsulated n-hexadecane and n-octadecane with poly(methylmethacrylate-co-2-hydroxy ethyl methacrylate) shell was prepared. Microcapsules were fabricated using oil-in-water emulsion polymerization method. Their chemical structure, microstructure, thermal energy storage properties and thermal stability were analyzed by Fourier-transform infrared spectroscopy, polarized light microscope, differential scanning calorimeter and thermogravimetric analyzer, respectively. The mean particle size was tested by a particle sized instrument. The microcapsules were applied to the wool and cotton fabrics using pad-dry-cure method. The thermo-regulating property of the fabrics was evaluated using the T-History test. The distribution and durability of the microcapsules on the fabrics was investigated with scanning electron microscopy. Findings: Spherical microcapsules with p(MMA-co-HEMA) shell and n-alkane core have been produced successfully. n-hexadecane in microcapsule solidifies at 14.8?15.6°C with the latent heat of 65.6?129.8 J/g and melts at 16.7?16.9°C with the latent heat of 67.6?136.9 J/g. Microencapsulated n-octadecane solidifies at 25.8?26.3°C with the latent heat of 74.1?106.2 J/g and melts at 26.8?27.4°C with the latent heat of 80.3?113.4 J/g. The microcapsules have enough thermal stability to the temperature of 150°C that was applied during the fixation of microcapsules on the fabric. The thermo-regulating effect of the microcapsule-incorporated fabrics has been proved by the T-history test. Originality/value: PCM microcapsules with p(MMA-co-HEMA) shell and n-hexadecane and n-octadecane core have been produced and their usage to produce thermo-regulating textiles have been proved. To determine the thermo-regulating property of the fabrics treated with these new PCM microcapsules, a T-History system has been designed. © 2018, Emerald Publishing Limited.111M484The authors would like to acknowledge the financial support by the Scientific and Technological Council of Turkey (Project No. 111M484)