Studies On The Preparation And Properties Of Form-stable Phase Change Materials SMA-g-PCM

In this thesis, graft form-stable phase change materials were synthesized by the reaction of SMA and PCM. The SMA chain has the function of form-stable, and the PCM chain has the function of energy storage.SMA was prepared by precipitation polymerization and solution polymerization with BPO as initiator. The influence of polymerization temperature, initiator dosage, ratio of styrene to maleic anhydride, monomer concentration and reaction time on polymerization was discussed in detail. The results showed that the yield of the SMAa (precipitation polymerization copolymer) reached 96.6%under the conditions of 80℃of polymerization temperature,1:1 of molar ratio of styrene to maleic anhydride,0.7%of initiator dosage and 2h of reaction time, and the yield of the SMAb (solution polymerization copolymer) reached 99.0%under the conditions of 80℃of polymerization temperature,0.6%of initiator dosage,1:1 of molar ratio of styrene to maleic anhydride,15%of monomer concentration and 4h of reaction time.Three kinds of fatty alcohols (n-butanol, n-octanol, n-octadecanol) were grafted on the SMAaby graft reaction. The influence of reaction temperature, reactant concentration, reaction time on the yield of SMAa-g-butanol was discussed in detail. The results showed that the yield of SMAa-g-butanol reached 99.0%under the conditions of 80℃of reaction temperature,15% of reactant concentration, and 8h of reaction time. Their energy storage capability was studied by DSC. The results showed that:SMAa-g-butanol, SMAa-g-octanol, SMAa-g-octadecanol had no energy storage capability.Different molecular weight polyethylene glycol (PEG20000, PEG 10000, PEG6000) were grafted on the SMA by graft reaction. Took SMAa and PEG6000 for example, the influence of solvent on the yield of SMAa-g-PEG6000 was discussed in detail. The results showed that the yield of SMAa-g-PEG6000 reached 98.0%under the conditions of toluene as solvent and 60℃of reaction temperature. The structure was proved by IR spectra.The energy storage capability, crystallinity, thermal stability and form-stable were studied by DSC, XRD, TG and the form of SMA-g-PEG in different temperatures. The results showed that the phase change enthalpy of SMAa-g-PEG20000(79%), SMAa-g-PEG 10000 (69%), SMAa-g-PEG6000(58%), SMAb-g-PEG20000(69%) were 125.2kJ/kg,106.3kJ/kg, 70.1kJ/kg,75.3kJ/kg respectively. TG results showed that:SMAa-g-PEG and SMAb-g-PEG were very stable before 250℃; XRD results showed that the crystallinity of SMAa-g-PEG and SMAb-g-PEG were slightly lower than PEG.The form of SMA-g-PEG in different temperatures showed that:SMAa-g-PEG and SMAb-g-PEG had good shape stability than the pure PEG.