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Recently,research on the synthesis and characterization of complex molecular architectures such as graft or comb-like copolymers has attracted great attentions due to their unique physicochemical properties and widely application range.[1] In this research,a series of PMMA-type comb-like polymers with different molecular structures were synthesized; the obtained molecules had both epoxide groups and PMMA side chains,which randomly distributed along the PMMA backbone; then the effect of the side chains on the thermal properties was investigated.The main results are as follows: firstly,from DSC data,all comb-like copolymers exhibit two distinct transitions at about 116 ℃ and-20 ℃,while linear copolymer and commercial PMMA shows only one glass transition temperature corresponding to the relaxation of the main chain(Figure 1),which confirm the existence of the PMMA side chains; Secondly,from DMA data,the activation energy for β transition of the polymers decreases with the incorporation of long side chains,which is attributed to the increased free volumes for the grafted topologies(table 2); Finally,from TGA results,the introduction of the side chains into the molecules lead to a significant improvement of thermal stability(Figure 2).