Accession Number:

ADA605645

Title:

Mechanochemical Strengthening of a Synthetic Polymer in Response to Typically Destructive Shear Forces

Descriptive Note:

Journal article

Corporate Author:

ILLINOIS UNIV AT URBANA-CHAMPAIGN

Report Date:

2013-08-04

Pagination or Media Count:

8.0

Abstract:

High shear stresses are known to trigger destructive bond-scission reactions in polymers. Recent work has shown that the same shear forces can be used to accelerate non-destructive reactions in mechanophores along polymer backbones, and it is demonstrated here that such mechanochemical reactions can be used to strengthen a polymer subjected to otherwise destructive shear forces. Polybutadiene was functionalized with dibromocyclopropane mechanophores, whose mechanical activation generates allylic bromides that are crosslinked in situ by nucleophilic substitution reactions with carboxylates. The crosslinking is activated efficiently by shear forces both in solvated systems and in bulk materials, and the resulting covalent polymer networks possess moduli that are orders-ofmagnitude greater than those of the unactivated polymers. These molecular-level responses and their impact on polymer properties have implications for the design of materials that, like biological materials, actively remodel locally as a function of their physical environment.

Subject Categories:

  • Inorganic Chemistry
  • Polymer Chemistry
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE