Linear low-density polyethylene (LLDPE) was functionalized with succinimide under different experimental conditions like change in time, temperature, and (% weight of succinimide). The FTIR Spectrum inferred that melt grafting of succinimide onto LLDPE followed the 0.50 order of reaction with respect to (% weight of succinimide). DSC was used to analyze the (melting temperature) T m and (crystallization temperature) T c values of functionalized LLDPE. Free radical mechanism explained the formation of nitroxide radical during the melt functionalization of N-hydroxy succinimide (NHS) with LLDPE in the presence of dicumyl peroxide.