A Loop-Opening Model for the Intrinsic Fracture Energy of Polymer Networks

TL;DR

This paper introduces a loop-opening model that explains the intrinsic fracture energy of polymer networks by considering molecular details, including chain scission and network continuum effects, aligning well with experimental data.

Contribution

The paper presents a novel loop-opening model that incorporates molecular-level details to predict the intrinsic fracture energy of polymer networks.

Findings

Model accurately predicts fracture energy across different polymer networks.

Fracture energy scales with product of fracture force and loop contour length.

Aligns well with experimental measurements of polymer network fracture.

Abstract

We present a loop-opening model that accounts for the molecular details of the intrinsic fracture energy for fracturing polymer networks. This model includes not only the energy released from the scission of bridging chains but also the subsequent energy released from the network continuum. Scission of a bridging chain releases the crosslinks and opens the corresponding topological loop. The released crosslinks will be caught by the opened loop to reach a new force-balanced state. The amount of energy released from the network continuum is limited by the stretchability of the opened loop. Based on this loop-opening process, we suggest that the intrinsics fracture energy per broken chain approximately scales with the product of the fracture force and the contour length of the opened loop. This model predicts an intrinsic fracture energy that aligns well with various experimental data on the fracture of polymer networks.