Preparation And Properties Of CDA-Based Solid-Solid Phase Change Materials

Latent heat energy storage is one of the most efficient ways of storing thermal energy. More than ten years, research about the phase change materials (PCM) have been a common concern international subject. It has a wide range of application in the solar energy utilization, thermal energy recovery, air conditioning, heat preservation clothing, energy storage cooker, building and aerospace.This paper is composed of three parts. In the first part, a series of the comb-like solid-solid phase change material MPEGs-g-CDA with different phase change temperature were synthesized. The methoxy polyethylene glycol (MPEG1200 and MPEG2000) with different molecular weight,according to the different molar ratio and methyl diisoeyanate (MDI),were grafted on the cellulose diacetate (CDA) through the solution polymerization. The structure characteristics, the phase change property, the crystallization property and thermal property of MPEGs-g-CDA were analyzed by FT-IR, DSC, POM and the thermometer, and the optimum condition was determined. The results showed that the grafting ratio of prepared MPEGs-g-CDA at the optimum process was reached to 549.05%, the phase change enthalpy was of 111.03J/g. The product with phase change temperature from 25.79℃to 43.33℃can be prepared by changing the molar ratio of MPEG2000 and MPEG1200. Also, it can be seen that the MPEGs-g-CDA has the good phase change property in the macro-lever through the determination of heating-cooling curves. The MPEGs-g-CDA can be used in the spinning or finishing of fabric to prepare the phase change fiber or phase change fabric that further expand the application range because the MPEGs-g-CDA can be dissolved in organic solvent such as acetone and DMF. In the second part, the acetone and the mixture of acetone and DMF were chosen as solvent respectively, and the CDA was chosen as base materials, the MPEGs-g-CDA was used as phase change materials, the phase change and temperature adjustment fiber was prepared by the electronic spinning. The factors were discussed, containing the solvent composition, the spinning voltage and the concentration of spinning solution effected on the morphology of the fiber. The morphology of the fiber, the phase change property and thermal property were analyzed by using SEM, DSC and TGA. The results showed that the average diameter of prepared fiber was 830 nm, the phase change enthalpy can reach to 30.396J/g. It has the good phase change and temperature adjustment property. In the last part, the phase change and temperature adjustment fabric was prepared by the direct coating method. The aqueous Polyurethane (PU) was chosen as coating reagents which containing the solid-solid phase change materials prepared to coat the polyester/cotton blended matrix fabric. The factors were discussed, containing the coating thickness, the concentration of Carboxymethyl cellulose (CMC) and the content of the MPEGs-g-CDA effected on the gas permeability, water vapor permeability, cold-warm sensation, heat conductivility and the phase change property of the coated fabric. The finished process was optimized and the standard durability test was performed on the finished fabric. The results showed that the coated weight of the fabric was 15g/m2 and the phase change temperature was between 38~40℃, the phase change enthalpy reached to 51.745J/g. The fabric had the suitable phase change temperature and high phase change enthalpy, while the phase change and temperature adjustment performance was obtained, all aspects of its performance can still be maintained or improved.