Elastic modulus and yield strength of semicrystalline polymers with bond disorder are higher than in atomic crystals

We perform thorough molecular-dynamics simulations to compare elasticity and yielding of atomic crystals and model semicrystalline polymers, the latter characterized by very similar positional ordering with respect to atomic crystals and considerable bond disorder. We find that the elastic modulus G, the shear yield strength, τY, and the critical yield strain εc of semicrystalline polymers are higher than (G, τY), or comparable to (εc), the corresponding ones of atomic crystals. The findings suggest that the bond disorder suppresses dislocation-mediated plasticity in polymeric solids with positional order.