Characterization of Mechanical Properties of Interphase in Glass/Polyester Composite System.
Abstract
A bimaterial pair consisting of homopolymers PMMA (polymethylmethacrylate) and PS (polystyrene) was selected for this study. A graft copolymer was used to bind the two homopolymers together. Instead of the conventional asymmetric double cantilever beam test we selected the asymmetric four-point-bend test scheme to evaluate the bimaterial system, because the latter can be employed to evaluate the effect of mode mixity. The mechanical properties of PMMA and PS are quite similar; thus the resulting Dunder's parameters are very small. Yet the material pair exhibits strong characteristics of a typical bimaterial. As it turned out the two materials have distinctly different fracture mechanisms. PMMA fails by generating a large amount of microcrack whereas PS fails by crazing which consumes much more energy. Depending upon the mode mixity an interfacial crack can be driven either into PMMA or into PS. And the resulting fracture toughnesses are quite different. Detailed strain distributions at the crack tips were mapped by the micromechanics technique called SIEM (Speckle Interferometry with Electron Microscopy) which provides the foundation for the fracture mechanism.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1997
- Accession Number
- ADA344296
Entities
People
- Fu Pen Chiang
Organizations
- Stony Brook University