Leveraging the thermal, mechanical, rheological and gas barrier properties of boron nitride reinforced high density polyethylene nanocomposites

This study investigates the influence of boron nitride (BN) nanosheets on the thermal, mechanical, rheological, and gas barrier properties of high-density polyethylene (HDPE) nanocomposites prepared via two distinct routes: conventional direct melt mixing and a novel solvent-assisted sonication method, where BN was dispersed in multiple solvents (optimized with propanol), coated onto HDPE pellets, and subsequently melt-mixed. BN loadings of 1 to 5 wt% were evaluated to elucidate the effect of filler concentration and dispersion on composite performance. The direct melt mixing caused agglomeration of BN nanosheets (BNNS) in HDPE, resulting in thermal instability, while the solvent-assisted route improved interfacial interactions and uniform BN dispersion resulting in superior property enhancement. Comprehensive analysis of the resulting nanocomposites revealed substantial improvements in thermal conductivity, mechanical strength, creep resistance, melt rheology, and gas barrier properties compared to neat HDPE. Thermal stability increased with BN content, evidenced by elevated onset degradation temperatures and higher char residues. X-ray diffraction and differential scanning calorimetry indicated enhanced crystallinity facilitated by BNNS. Mechanical tests demonstrated increased tensile strength and modulus, with reduced creep deformation attributable to strong filler–matrix adhesion. Rheological behavior showed improved processability, while gas permeability tests confirmed marked barrier property enhancement, attributed to the tortuous path created by dispersed BNNS. These findings highlight the critical role of BN concentration and dispersion methodology in tailoring HDPE-based nanocomposites for advanced performance. The results offer valuable insights for developing multifunctional HDPE/BN nanocomposites suitable for demanding applications in thermal management, packaging, electronics, structural and protective materials.