Application of Optical Methods, Including Optical Interference, to Measure the Dimensional Stability of Resins, Resin Based Adhesives and Resin Based Composites.
Abstract
As a consequence of osmosis during water uptake in the case of polycarbonates and as a consequence of osmosis followed by freezing of the aqueous solutions associated with osmosis in polyesters and epoxies, hairline cracks have been observed. The cracks are filled with water solution, and the small mismatch in acoustic impedance between polymer and water makes them extremely difficult to detect with ultrasound. Although the cracks are as much as a millimeter in lateral dimensions, the small separation between fracture surfaces and hence the small size of the crack volume makes for difficult detection by radiographic techniques. Specialised optical techniques, including rectified optics transmission microscopy and interferometry, appear to be the most satisfactory methods for their observation. These techniques have been used in the present studies and have permitted estimates to be made of the stress intensity factors at which hairline cracking occurs in each of the three polymers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1983
- Accession Number
- ADA140297
Entities
People
- J. P. Sargent
- K. H. G. Ashbee
Organizations
- University of Bristol