Effects of alumina nanoparticles on the thermo-elastic constants of unidirectional short glass fiber-reinforced polyethylene composites: A finite element analysis

In the pursuit of advanced materials with enhanced thermo-mechanical properties, unidirectional short glass fiber (USGF)-reinforced polyethylene composites incorporating alumina nanoparticles can represent a potentially promising development. This study shows the constructive interplay between the multiscale agents, nanofiller/polymer interphase and the overall composite performance, employing the concept of representative volume element (RVE) and the finite element analysis. First, an RVE is created with spherical alumina nanoparticles dispersed randomly within the polyethylene matrix. Next, a different RVE is formed where USGFs are incorporated into the nanoparticle-filled polymer, which serves as the base material. By analyzing the RVEs via the finite element method (FEM), the elastic moduli and coefficients of thermal expansion (CTEs) of the ternary composites are predicted. The validity of the numerical model is assessed by comparison with previous literature, providing an acceptable agreement. The effects of volume fraction and geometry of alumina nanoscale particles and glass microscale fibers on the thermo-elastic constants are investigated. The findings indicate that dispersing alumina nanoparticles into the polyethylene can improve the thermo-elastic properties of the ternary composites. The elastic modulus and CTE in the transverse direction is significantly improved by reducing the diameter of alumina nanoparticles. It is found that nanofiller/polymer interphase region affects mostly the transverse thermo-elastic properties.