Molecular Damage Detection in an Elastomer Nanocomposite with a Coumarin Dimer Mechanophore
| Autor: | Bobin Lee, Marc Couty, Constantine Y. Khripin, Gregory R. Gossweiler, Stephen L. Craig, Yudi Zhang, Ethen Thomas Lund, Zhenbin Niu, Etienne Munch |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Nanocomposite Materials science Polymers and Plastics Polymer nanocomposite Polymers Dimer Organic Chemistry Vulcanization Polymer Elastomer Photochemistry Fluorescence spectroscopy law.invention Nanocomposites chemistry.chemical_compound Polybutadiene chemistry Elastomers law Coumarins Materials Chemistry Stress Mechanical |
| Zdroj: | Macromolecular rapid communications. 42(1) |
| ISSN: | 1521-3927 |
| Popis: | Molecular force probes that generate optical responses to critical levels of mechanical stress (mechanochromophores) are increasingly attractive tools for identifying molecular sites that are most prone to failure. Here, a coumarin dimer mechanophore whose mechanical strength is comparable to that of the sulfur-sulfur bonds found in vulcanized rubbers is reported. It is further shown that the strain-induced scission of the coumarin dimer within the matrix of a particle-reinforced polybutadiene-based co-polymer can be detected and quantified by fluorescence spectroscopy, when cylinders of the nanocomposite are subjected to unconstrained uniaxial stress. The extent of the scission suggests that the coumarin dimers are molecular "weak links" within the matrix, and, by analogy, sulfur bridges are likely to be the same in vulcanized rubbers. The mechanophore is embedded in polymer main chains, grafting agent, and cross-linker positions in a polymer composite in order to generate experimental data to understand how macroscopic mechanical stress is transferred at the molecular scale especially in highly entangled cross-linked polymer nanocomposite. Finally, the extent of activation is enhanced by approximately an order of magnitude by changing the regiochemistry and stereochemistry of the coumarin dimer and embedding the mechanophore at the heterointerface of the particle-reinforced elastomer. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text