Abstract
Polymer nanocomposites based on low-density polyethylene (LDPE), containing 1.5, 3, and 6 wt.% of aluminum oxide (Al2O3), are fabricated by melt-mixing and injection-molding. The effective ratio of nanoparticles that maximize the mechanical behavior of LDPE composites was estimated using different techniques. The nanomechanical (nanohardness, nanomodulus) properties were studied using the nanoindentation technique. An Instron testing machine and a dynamic mechanical analyzer were utilized to study the flexural and viscoelastic behaviour (storage, Loss modulus, creep-relaxation rate and creep compliance) of the nanocomposites. Generally, the nanoindentation results indicated that the hardness and modulus of LDPE composite improved due to the addition of nanoparticles. In addition, the viscoelastic results indicated that the addition of nanoparticles improves the shear modulus, creep resistance and relaxation behaviour of the tested composite. On the other hand, the creep compliance decreased due to addition of nanoparticles. The results of tests that performed in this study indicated that the maximum improvements in the LDPE matrix mechanical behaviour were observed when composited with nanoparticle of 1.5 wt.%. A slight reduction in these properties was observed when the loading of nanoparticles increased more than that ratio but still superior to those of the pure LDPE matrix.