Fabrication of low emissivity paint for thermal/NIR radiation insulation for domestic applications

Recently, low-emissivity paint has gained more importance than commercial paints. Low emissivity (Low-E) Paint also termed as a coating for radiation control, in which the emissivity of radiations of longer waves are reduced dramatically (i.e., the emissivity of commercially available paint is 0.9) by imparting low emissivity particles in the base paint but not suitable to reduce near-infrared radiation. Commercially available paints as of today have minimum of 0.7 emissivity and it does not give any significant energy saving. The low emissivity property of paint makes it particularly suitable for reducing the radiative heat exchange in many domestic applications i.e., home electronics, building construction components, roof surfaces, heat storage tanks, and pipes, etc in result, low power required to heat or cool the building in respective whether conditions. In this work, different samples of white paint were prepared in the lab by using a low shear mixer (mechanical stirrer) under very controlled conditions and studied the results of dry paint films to reduce the thermal emissivity then commercially available paint. Then we investigate the drying time of the wet paint films and analyze thermal heat into visible light through thermal imaging camera, Crosshatch, and IR transmission. We also studied the emissivity through ET-100 and aging stability through a weather-o-meter instrument, which investigated that emissivity value achieved in the range of 0.4–0.6 than commercial paints. The results showed that paint exhibits an acceptable aesthetic emissivity value of ∼0.60. It was calculated theoretically that by the use of this novel Low-E paint, annually about 20%–25% less energy will be consumed in building for cooling or heating.The Open Access funding is provided by the Qatar National Library, Al Rayyan Doha Qatar . We are also thankful to everyone who supported and assisted us in completing this work. Our appreciations and thanks also go to our colleagues and laboratory engineers at National Textile University, Faisalabad, Pakistan and also Northwestern Polytechnical University, Xi’an, China

Synthesis of catalyzed polyurethane films using varying content of isocyanates, glycols, and chain extenders

Polyurethane (PU) films are regarded as an important polymeric class in coating sectors. PU exhibits various advantageous features like coatings to shield metals and wooden objects, adhesives, sealants, and elastomeric properties in a broader perspective to boost the appearance and packaging. In the medical field, PU shows bactericidal qualities for real-world uses, but efforts are required to strengthen the antibacterial characteristics in polyurethane films. The present research is intended to develop five (05) different novel polyurethane films with excellent anti-bacterial properties. Polyurethane films were prepared using isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI) as aliphatic diisocyanate, 1, 4-Butanediol (BDO) as chain extender, and Polytetra-methylene glycol-1000 (PTMG-1000) and Polytetra-methylene glycol-2000 (PTMG-2000) as glycol. The reaction was conducted in a polymerization chamber using 2,2-Dimorpholinodiethylether (DMDEE) and 4–4, bioxdimorphline as a catalyst. Surface morphology and characteristics, thermal stability, tensile and viscoelastic properties were characterized using SEM, XRD, FTIR, contact angle, TMA, tensile and rheometry testing. Furthermore, an anti-bacterial test was performed to confirm PU film usage as an occlusive dressing. FTIR results of PU films based on PTMG2000 & IPDI, PTMG1000 & IPDI, and PTMG2000 & HDI showed an increase in hydrogen bonding with the intensity of the C = O band when the NCO: OH concentration was increased. But due to incompatibility of the (OH) soft segment of glycol with the hard (NCO) segment of isocyanate caused a drop in the peak strength of PU films based on PTMG2000 & HDI and PTMG1000 & IPDI. The tensile strength is trending upward for these PU samples PTMG2000 & IPDI, PTMG1000 & IPDI, and PTMG2000 & HDI. While the PTMG2000 & HDI polyurethane sample has the highest tensile strength (105 MPa) and the lowest elongation (12.2 %) at break point. (XRD and (SEM) Results showed that the crystallinity of the synthesized polyurethane films was affected by varying the NCO: OH content and this content favored the formation of ordered structure as higher peak intensities in these PU samples PTMG2000 & IPDI, PTMG1000 & IPDI, and PTMG2000 & HDI