Fabrication, structures and properties of nano/microencapsulated phase change materials, thermo-regulated fibres and fabrics

This project aims to fabricate and characterize the structures and properties of thermo-regulated fibres and fabrics that can intelligently regulate temperature by absorbing and evolving latent heat, to enhance the development of temperature regulating fabrics and improve the thermo-physiological comfort of textile materials.; In this study, nano/microencapsulated n-alkanes (Nano/MicroPCMs) were synthesized by in-situ polymerization of urea-melamine-formaldehyde. Parameters affecting the structures, thermal stabilities and properties of Nano/MicroPCMs, such as oil phase composition and content of cyclohexane, shell composition, stirring rates, content of emulsion and heat-treatment on the properties of MicroPCMs were studied. To analyze the effects of increased content of Nano/MicroPCMs, polypropylene (PP) composite fibres containing 4--24wt% MicroPCMs and polyacrylonitrile-vinylidene chloride (PAN/VDC) fibres containing 5--40wt% Nano/MicroPCMs were melt and wet-spun respectively. The composition and properties of thermo-regulated nonwoven fabrics made of the fibres, PET and PP fibres and Nano/MicroPCMs coated knitted fabric were also studied.; The heat absorbing and evolving temperatures of the melt-spun fibres in which the microcapsules were evenly impregnated in core polymer matrix were approximately 32°C and 15°C respectively. The spinnability of the fibre was affected by content of MicroPCMs, diameters, ratio of aggregate microcapsules and spinning parameters etc. The wet-spun fibre had a higher efficiency of enthalpy of melting than that of the melt-spun one.; The fabrics absorbed and released heat at 25--34°C and 10--25°C respectively. The knitted fabrics absorbed and released heat at 32°C and 17°C respectively with an amount of 8--20J/g. The integral heat flux of MicroPCMs coated fabric is significantly higher than that of the control. (Abstract shortened by UMI.)...