Accession Number : ADA140297

Title :   Application of Optical Methods, Including Optical Interference, to Measure the Dimensional Stability of Resins, Resin Based Adhesives and Resin Based Composites.

Descriptive Note : Annual progress rept. no. 1,

Corporate Author : BRISTOL UNIV (ENGLAND) H H WILLS PHYSICS LAB

Personal Author(s) : Ashbee,K H G ; Sargent,J P

PDF Url : ADA140297

Report Date : Dec 1983

Pagination or Media Count : 42

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.

Descriptors :   *Polymers, *Epoxy compounds, *Epoxy resins, *Stability, *Adhesives, *Composite materials, *Optical properties, *Cracks, Fracture(Mechanics), Transparencies, Light transmission, Stress concentration, Absorption, Water, Interference, Toughness, Osmosis, Caustics, Polycarbonates, Polyethers, Modulus of elasticity, Mechanical properties, Equations, Mathematical prediction

Subject Categories : Adhesives, Seals and Binders
      Laminates and Composite Materials
      Plastics
      Optics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE