Engineering design : eicosane microcapsules synthesis and application in polyurethane foams aiming to diminish wheelchair cushion effect on skin temperature

Abstract

Thermal comfort of wheelchairs still requires improvements, since users remain on the chair for as long as 12 h a day. Increased sweating makes the skin more susceptible to colonization by fungi and bacteria, and may cause pressure ulcers. In this sense, the microencapsulation of Phase-Change Materials (PCMs) may help to enhance wheelchair cushion comfort by regulating heat exchange. This study describes the production of PCM microcapsules and their application in flexible polyurethane foams after expansion, and assesses improvements in heat exchange. Microcapsules with eicosane core coated with melamine-formaldehyde were produced. Eicosane is a thermoregulation agent whose phase-change temperature is near that of the human body’s. Microcapsules were characterized by thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. Then, microcapsules were applied on polyurethane foams by vacuum filtration and high-pressure air gun. Samples were exposed to a heat source and analysed by infrared thermography. The results indicate that thermal load increased in samples treated with microcapsules, especially by pressure air gun, and show that it is possible to enhance thermal comfort in wheelchair seats. Thereby, this study contributes to enhance quality of life for wheelchair users, focusing on thermal comfort provided by cushion seats made from PU foam.