<p>The current study investigates the synergistic role of styrene monomer (St) in enhancing the grafting efficiency of the maleic anhydride on the linear low-density polyethylene (LLDPE), focusing on the interfacial adhesion strength in tie layer adhesives. The MA was grafted onto the polyethylene backbone using dicumyl peroxide (DCP) initiator and evaluated in terms of grafting degree regarding the DCP concentration, MA concentration, and styrene monomer incorporation. The results indicated that the amount of initiator and MA directly influences the grafting degree in the reaction, so an optimum amount is preferred. Furthermore, the incorporation of styrene significantly improves grafting efficiency, hydrophilicity, and mechanical performance. Here, the highest MA grafting degree was obtained at about 1.12% using 0.5 wt% DCP and incorporating 3 wt% styrene monomer. T-peel tests confirmed that the adhesive strength increased with a grafting degree and tie layer thickness. The results proved the effectiveness of styrene monomer on the maleic anhydride grafting degree on and tie layer interfacial adhesion styrene.</p>