Abstract In this study, we have reported the synthesis of copolymers of poly(ethylene glycol) acrylate (PEGA) with methyl methacrylate (MMA) in various ratios which can be utilized as polymeric phase change materials (PCMs). The monomer reactivity ratio of PEGA copolymers was determined by Fineman-Ross method. The values of r1 (PEGA) and r2 (MMA) were found to be 0.8164 and 0.3371 respectively. The thermal analysis performed by DSC indicated high fusion enthalpy of 168 J·g−1 at 55 °C for the feed ratio of 40:60 of PEGA:MMA (Copolymer mole fraction of 76:24). The crystallization behaviour shows the presence of spherulites but of smaller size compared to PEG and with reduced crystallization ability. The results point out the capabilities of PEGA to function as an effective PCM which can be utilized for numerous thermal energy storage applications.