A Mechanical Model for Polyhedral Oligomeric Silsesquioxane (POSS) Reinforced Amorphous Polyethylene

The mechanical behavior of polyethylene (PE) co-polymerized with polyhedral oligomeric silsesquioxane (POSS) was studied by using molecular simulations. Simulation configurations consisted of aligned PE chains with POSS attached to the central chain and amorphous PE chains with different content POSS. From the simulations with aligned PE chains with POSS, it was found that the method for reinforcement was due to dislocation pile-up at POSS, and above a critical stress the dislocations traverse the POSS causing a sawtooth variation in the load-displacement curve. The stress-strain curves for amorphous PE-POSS bulk showed distinct elastic and plastic straining stages. Plastic straining consisted of hardening and slipping segments attributed to dislocation pile-up and chain sliding. Computational results were used to develop a reinforcement model to describe the mechanical response of PE-POSS bulk under uniaxial tension.