Of Pnipam Department Of Gel As A Carrier Compound Phase Change Material Preparation And Research

Solid-liquid phase change materials for thermal storage become theresearch hotspot because of its big phase change enthalpy at the presenttime. However, Solid-liquid phase change materials has a so big volumethat it is difficult to load when materials change solid to liquid. Aim atthis phenomenon, solid-liquid phase change materials for thermal storagewas compounded to polymer gel carriers in this paper. A kind ofnew-style composite materials which needn't container to fill wasprepared.Firstly, a serie of N-isopropylacrylamide (NIPAAm) copolymer gelswas investigated in this paper. Three homogeneous PNIPAm,P(NIPAm-co-BMA) and P(NIPAm-co-AAm) hydrogels with differenthydrophilicity were prepared from hydrophilic acrylamide (AAm) andhydrophobic butyl metha-crylate(BMA). Copolymer gels show negativethermo-sensitivities. Lower critical solution temperature (LCST),equilibrium swelling degree and the initial swelling rate increase as thehydrophilicity of gels increases. Swelling behavior in six different sodiumsalt solution were researched. Experimental results shows three gels shownegative thermo-sensitivities in salt solution , temperature responsiveperformance weakens compared with water. Swelling rate becomesslower and Equilibrium swelling ratios is small with increasing ofConcentration for salt under 20℃,Time for swelling equilibrium is longerin salt solution than that in water, furthermore, equilibrium swelling ratiosin sodium salt solution are all smaller than that in water when under thesame temperature.Secondly, organical composite thermal storage materials which takethe PNIPAAm gels as the carriers and the palmitic acid and the lauric acidmixture for phase change materials were Synthesized by radicalpolymerization ,and organical/inorganical composite materials which takeP(NIPAAm-co-AAm) gels as the carriers and the palmitic acid,thelauric acid and Na₂HPO₄·12H₂O mixture were also Synthesized byradical polymerization. Structure and thermal performance of twocomposite material were characterized and analyzed by infrared spectroscopy and differential scanning calorimetry, thermogravimetricand Scanning Electron Microscope. The influence of organic acid and theinorganic salt percentage on phase change enthalpy and transfertemperature studied. It finds out that phase change temperature andenthalpy for two composite material increase, Phase change material andgels are more compatible along with organic acid content increasing. Twokind of materials weightlessness rate all only have about 1%.For composite material of PNIPAAm gels and mixture acid, the phasechange enthalpy is 105 j.g^-1 when the mixed acid content achieved 76%the enthalpy is bigger than 100 J·g^-1when adding Na₂HPO₄.12H₂O,withthe quality proportion for organic acid and inorganic salt increasing, thephase change temperature scope changes narrowly. Na₂HPO₄·12H₂O stillmaintains the original nature in the compound materials.