Why is the strength of an elastomeric polymer network so low?

Fuente: arXiv
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Autori principali: Mohanty, Shaswat, Blanchet, Jose, Suo, Zhigang, Cai, Wei
Natura: Preprint
Pubblicazione: 2025
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author Mohanty, Shaswat
Blanchet, Jose
Suo, Zhigang
Cai, Wei
author_facet Mohanty, Shaswat
Blanchet, Jose
Suo, Zhigang
Cai, Wei
contents Experiments have long shown that a polymer network of covalent bonds commonly ruptures at a stress that is orders of magnitude lower than the strength of the covalent bonds. Here we investigate this large reduction in strength by coarse-grained molecular dynamics simulations. We show that the network ruptures by sequentially breaking a small fraction of bonds, and that each broken bond lies on the minimum "shortest path". The shortest path is the path of the fewest bonds that connect two monomers at the opposite ends of the network. As the network is stretched, the minimum shortest path straightens and bears high tension set by covalent bonds, while most strands off the path deform by entropic elasticity. After a bond on the minimum shortest path breaks, the process repeats for the next minimum shortest path. As the network is stretched and bonds are broken, the scatter in lengths of the shortest paths first narrows, causing stress to rise, and then broadens, causing stress to decline. This sequential breaking of a small fraction of bonds causes the network to rupture at a stress that is orders of magnitude below the strength of the covalent bonds.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11339
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Why is the strength of an elastomeric polymer network so low?
Mohanty, Shaswat
Blanchet, Jose
Suo, Zhigang
Cai, Wei
Soft Condensed Matter
Materials Science
Statistical Mechanics
Computational Physics
Experiments have long shown that a polymer network of covalent bonds commonly ruptures at a stress that is orders of magnitude lower than the strength of the covalent bonds. Here we investigate this large reduction in strength by coarse-grained molecular dynamics simulations. We show that the network ruptures by sequentially breaking a small fraction of bonds, and that each broken bond lies on the minimum "shortest path". The shortest path is the path of the fewest bonds that connect two monomers at the opposite ends of the network. As the network is stretched, the minimum shortest path straightens and bears high tension set by covalent bonds, while most strands off the path deform by entropic elasticity. After a bond on the minimum shortest path breaks, the process repeats for the next minimum shortest path. As the network is stretched and bonds are broken, the scatter in lengths of the shortest paths first narrows, causing stress to rise, and then broadens, causing stress to decline. This sequential breaking of a small fraction of bonds causes the network to rupture at a stress that is orders of magnitude below the strength of the covalent bonds.
title Why is the strength of an elastomeric polymer network so low?
topic Soft Condensed Matter
Materials Science
Statistical Mechanics
Computational Physics
url https://arxiv.org/abs/2502.11339