Crazing Reveals an Entanglement Network in Glassy Ring Polymers

Molecular simulations are used to show that an entanglement network exists in nonconcatenated ring polymers of sufficiently long contour length when they are cooled down well below the glass transition temperature. The entanglement network consists of only a fraction of the topological constraints that force ring polymers to be in self-similar globular conformations. The entanglement network can support stable craze formation in ring polymer glass under tensile loading. The structural features of the ring polymer craze and the drawing stress during the craze formation are related to the underlying entanglement network by generalizing traditional models for the crazing in linear polymer glass. The computer simulations and theoretical analysis demonstrate tuning polymer topology as a promising way to manipulate the mechanical properties of traditional plastic materials.