Synthesis and characterization of an environmentally friendly PHBV/PEG copolymer network as a phase change material

Novel environmentally friendly poly（hydroxybutyrate-co-hydroxyvalerate） and poly（ethylene glycol） （PHBV/PEG） copolymer networks were synthesized through free-radical solution polymerization with PHBV diacrylate （PHBVDA） and polyethylene glycol diacrylate （PEGDA） as macromers. The molecular structure of PHBV/PEG copolymer network was characterized by Fourier transform infrared （FT-IR） and 1H nuclear magnetic resonance （1H NMR）. The morphology of the PHBV/PEG co- polymer network was characterized by polarization optical microscopy. Thermal energy storage properties, thermal reliability and thermal stability were investigated by differential scanning calorimetry （DSC） and thermogravimetric analysis. The results indicated that the PHBV/PEG copolymer network hindered the growth of PEG crystalline segments or PHBV segments. PHBV/PEG copolymer network had a higher latent heat enthalpy, which didn＇t reduce with the components of PHBV in- creased. Moreover, PHBV/PEG copolymer network still had good thermal stability even at 300 ~C. These results suggested that such environmentally friendly copolymer network would have wide applications in phase change energy storage materials.