Thermo-mechanical properties of silica-reinforced PLA nanocomposites using molecular dynamics: The effect of nanofiller radius

In this study, the elastic mechanical properties of heat deflection temperature (HDT) of a polymeric matrix composite reinforced with silica particles have been studied at the atomic scale by the molecular dynamics simulation method. Ten atomic samples including pure PLA and 9 nanocomposites with 1, 2, and 3% of volume fractions of silica nanoparticles with different atomic radii of 20, 30, and 50 Å, were constructed. The Young’s modulus of these samples has been calculated after equilibrium and applying the NVT ensemble. Moreover, the variations of Young’s modulus with temperature were measured for different atomic models and the HDT for the nanocomposites were extracted. The results of the simulations showed that the sample with a 20 Å radius of nanoparticle and volume fraction of 3% had the largest Young’s modulus compared to other samples. In this sample, Young’s modulus has reached 5193 MPa, which has shown a 238% increase compared to the pure polymer. Also, the value of the HDT in this sample was calculated about modulus 119 C° about 133% higher than pure polymer. The obtained values of Young’s modulus and HDT for pure polymer showed a good agreement with the experimental results.