Preparation Of Phase Change Microcapsules By In-situ Polymerization And Application Of Coatings On Fabrics

Phase change materials have broad application space.This paper mainly discusses the cooling and heating regulation and protection performance of phase change microcapsules in the textile field.There are many types of phase change materials available on the market,but the thermal enthalpy values they provide are not able to adjust the microenvironment temperature to the comfort level required by the human body,and the production cost is high and the environment is not friendly.Therefore,a new type of design is designed.The phase change microcapsules achieve better thermal hysteresis when combined with fabric.Firstly,according to the application direction of the phase change microcapsules,the selection of a suitable phase change core material is a key factor for the phase change microcapsules to have a high heat enthalpy value.A suitable initiator,emulsifier,and solvent are selected according to the type of the shell material and the core material.The phase change microcapsules with high thermal enthalpy and stable performance were synthesized by in-situ polymerization.The specific experimental results are as follows:1)Since the phase transition temperature of n-octadecane is about 28°C,n-octadecane is selected as the phase change core material.Ethylene glycol dimethacrylate(EGDMA)is a shell material,azobisisobutyronitrile(AIBN)is used as an initiator,S-20 and Span-80 are emulsifiers,water is a solvent,and in-situ polymerization is used at 75.After reacting at°C for 4h and reacting at 85°C for 2h,phase change microcapsules with smooth surface,small particle size and high compactness were obtained.2)After analysis and discussion of the experimental results,when the amount of emulsifier is 20%(%core material),the HLB value is 10,the amount of initiator is 2%(%shell),the core/shell ratio is 2,and 1:1 After adding a soft monomer methyl methacrylate(MMA),a phase change microcapsule with an encapsulation ratio of up to 96.2%and an average particle diameter of 3.115?m can be obtained.Performance analysis of newly prepared phase-change microcapsules using various instruments,including infrared analysis(FTIR),scanning electron microscopy(SEM),differential scanning calorimetry(DSC),thermogravimetric analyzer(TGA),and laser particle size Analysis by instrument and other instruments shows that the microcapsules have small particle size and smooth surface.Although there are a few adhesions,the particle size is still mainly distributed between 1-5.3?m.After the shell material is encapsulated,the phase transition temperature and phase transition temperature range of the core material are not changed.The infrared analysis and analysis spectrum also indicates whether the characteristic peaks of n-octadecane and shell material appear in the phase change microcapsules.The shell material covered the core material well and did not react.The encapsulation of the shell material can increase the decomposition temperature of n-octadecane,and the addition of the soft monomer also improves the heat resistance of the phase change microcapsule.The phase change microcapsules prepared by the best process are processed onto the peach skin polyester fabric by coating method.The optimal process parameters are:30%phase change microcapsules,50%acrylate coating glue(glass transition temperature).?-30 degrees),20%deionized water,3%thickener,baked at 120°C for3 min,coating treatment twice.A coated fabric having a soft hand and a weight increase of about 74 g/m ~2 can be obtained.The coated polyester cool fabric was characterized by scanning electron microscopy(SEM),differential scanning calorimetry(DSC),instant contact cooling test(Q-Max)and whiteness test.The results showed that the microcapsules adhered to the fabric.After the surface,there is no obvious cracking phenomenon,the thermal enthalpy value can reach up to 36J/g,the temperature change range meets the requirements of human micro-environmental temperature,and the instantaneous coolness Q-Max value is 0.25J·(cm~2·s)-1.Meet the criteria for the evaluation of cool fabrics.