Enhancing the performance of high-density polyethylene using graphene: Compounding techniques and functional properties - a review

High-density polyethylene (HDPE) is widely used in industrial applications owing to its low material cost, favorable mechanical strength, chemical resistance, and excellent processability; however, its inherent limitations in thermal, electrical, and barrier properties restrict broader functional utility. Graphene, with its exceptional thermal conductivity, mechanical robustness, and large surface area, has emerged as a promising nanofiller to overcome these deficiencies. This review critically examines recent progress in fabricating HDPE/graphene nanocomposites, with an emphasis on the processing-structure-property relationships governing their performance. Attention is given to the influence of compounding techniques, such as melt mixing, solution blending, and in situ polymerization, on filler dispersion and interfacial compatibility. The review also discusses the fundamental reinforcement mechanisms governing stress transfer, crystallization behavior, and conductive network formation, together with the influence of graphene characteristics, compatibilization strategies, and processing conditions. Reported enhancements include improved mechanical performance, thermal stability, modified crystallinity, increased thermal conductivity, superior dielectric performance, tunable electrical conductivity, reduced gas permeability for barrier applications, altered rheological behavior, and enhanced wear resistance. Potential applications span packaging, piping, automotive, structural, and electrically functional materials, highlighting the versatility of these nanocomposites. The review further identifies existing challenges, such as agglomeration at high filler loadings and processing constraints, and outlines future research directions toward scalable manufacturing and multifunctional integration.