Preparation And Characterization Of Paraffin-microcapsule Phase Change Material

At present, the wall material of microcapsule phase change material is mainly themelamine resin, urea formaldehyde resin and other materials, and the core material ofmicrocapsule are single phase change materials. Melamine formaldehyde resin andurea formaldehyde resin as the structure of the problem itself, in the process of usingmicro capsules release harmful gases such as formaldehyde; microencapsulation ofsingle phase change material, the phase change temperature range is narrow, thesedisadvantages limit the applications of phase change materials. This paper selects theformaldehyde-free harmful gases such as styrene and methacrylic acid polymer as thewall material, are octadecane with butyl stearate as core materials, respectively isoctadecane phase change material microcapsule was prepared, butyl stearate phasechange material microcapsule and octadecane with butyl stearate as composite phasechange material microcapsule composite phase change materials.This paper adopts the dispersion polymerization of styrene-prepared bycopolymerization monomer as the wall material, are octadecane and butyl stearate asphase change material microcapsule core material, with the aid of scanning electronmicroscope (SEM), differential scanning calorimetry (DSC), thermogravimetricanalyzer (DTA, TG), laser particle size instrument testing instruments, such as theeffects of emulsifier, initiator, monomer, monomer and the ratio of core material onthe structure and properties of phase change materials of the preparation ofmicrocapsule, the influence of microcapsule of phase change material, surfacemorphology, particle size and distribution of the thermal properties have beencharacterized and analyzed. The preparation of microcapsule trial in the baptism ofcotton fabric finishing and coating, and the finishing of cotton fabrics after phasetransformation temperature adjustment function is evaluated. The experimental results show that:(1) the styrene-methyl acrylic polymer P(St-co-MAA) as wall material, is octadecane into a core material with phase changematerials can be successfully prepared microcapsules. Optimization of processconditions for: the ratio of styrene and methacrylic acid as the1:1ratio of3:1, corewall, using azodiisobutyronitrile,1.3%and3%sodium dodecyl sulfate in30min afterthe morphology of microcapsule has good dispersion, uniform particle sizedistribution. The average particle size of microcapsules was10.867microns; Moltenphase transition temperature of30.73℃, phase change enthalpy is as high as180j/g.(2) The styrene-methyl acrylic polymer P (St-co-MAA) as wall material, butylstearate as core material with phase change materials can be successfully preparedmicrocapsules. Optimization of process conditions for: using azodiisobutyronitrile,1.6%and2%sodium dodecyl sulfate, core wall when the ratio of1:1microcapsulesmorphology is better, more uniform particle distribution. The average particle size ofmicrocapsules was11.36microns; Molten phase transition temperature of21.5℃,phase change enthalpy value as high as104.05J/g, crystalline phase transitiontemperature of15.67℃, phase change enthalpy value of100.57J/g.(3) Theexperimental use octadecane and butyl stearate two different categories of phasechange materials to compound, with styrene and methyl acrylate polymer P (St-co-MAA) for microcapsule wall material, the preparation of microcapsule compositephase change materials. Optimization of process conditions for: usingazodiisobutyronitrile,1.8%and2%sodium dodecyl sulfate, determine the core wallratio of1:1ratio of4:6and two kinds of phase change materials,5:5,6:4microcapsules morphology is better, when particle size distribution is more uniform.The average particle size of microcapsules was11.42microns; when the proportion ofoctadecane with butyl stearate as4:6,5:5,6:4, microcapsules of heat enthalpy103J/g,respectively91.4J/g and87.2J/g, heat enthalpy is ideal.(4) the application of thephase change material microcapsule of homemade finishing of cotton pad method,when the dosage of cement is50%, the curing time is more than25min, rolling ratewas75%, the fabric has good air permeability, melting temperature of26.71℃, thephase transition enthalpy value of24.83J/g, heat enthalpy relatively ideal.(5)20%of the phase change material microcapsule using coating finishing method of finishingon the cotton fabric, fabric heat storage temperature adjustment function, and thermalproperties of the treated fabrics are measured. The results showed that the cottonfabric of molten phase transition temperature of26.03℃, phase change heat enthalpyvalue of25.16J/g, heat enthalpy relatively ideal.