High strain‐rate response of spiropyran mechanophores in PMMA
Abstract
We report the high strain‐rate response of a spiropyran (SP) mechanophore in poly(methylmethacrylate). Previous work on this system has demonstrated a reversible bond scission in the SP under local tensile force, converting it to a fluorescent merocyanine form. A Hopkinson bar was used to apply fast compressive loads at rates from 102 to 104 s−1, resulting in significant activation of the SP near fracture surfaces. However, comparison with a similar thermochromic SP reveals that much of the observed activation likely arises from thermal effects during high‐rate fracture. These results show the importance of a thermally active control system in distinguishing mechanochromic response during high‐rate loading. Microscale fluorescence mapping of the fracture surfaces using a confocal Raman microspectrometer suggests that some distinct mechanical activation may be occurring in craze‐like regions during fibril rupture. The thermal response of the SP is useful in its own right for characterizing plastic heating regions during dynamic fracture. Published 2014. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1347–1356
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 18, 2014
- Source ID
- 10.1002/polb.23569
Entities
People
- Brian P. Mason
- James R. Hemmer
- Javier Read de Alaniz
- Joseph P Hooper
- Matt Van Horn
- Patrick D. Smith
- Sebastian Osswald
- Sufian Alnemrat
Organizations
- Defense Threat Reduction Agency
- Naval Postgraduate School
- Naval Surface Warfare Center
- University of California, Santa Barbara