Environmentally enhanced crazing in polymers
The effects of low-molecular-weight chemicals on the physical integrity and failure modes of amorphous but crystallizable polycarbonate and crosslinked epoxy glasses are presented. Solvent-induced crystallization (SINC) is shown to play a role in the solvent-crazing mechanism of polycarbonate. A mechanically weak, cavitated, crazed surface layer is produced in polycarbonate as a result of a combination of volume decreases caused by SINC and liquid-induced dilatational swelling stresses together with the relaxation of fabrication stresses. The mechanism by which surface crazing in polycarbonate is enhanced by handling is also reported. In the epoxy studies, sorbed moisture plasticizes these crosslinked glasses and causes their mechanical properties to deteriorate. Studies of the initiation cavity and mirror regions of the fracture topographies of these epoxies indicate sorbed moisture enhances the craze initiation and propagation processes.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5897263
- Report Number(s):
- UCRL-82488; CONF-790917-2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360401* -- Polymers & Plastics-- Preparation & Fabrication-- (-1987)
360403 -- Materials-- Polymers & Plastics-- Mechanical Properties-- (-1987)
AMORPHOUS STATE
CARBON COMPOUNDS
CARBONATES
CRACKS
CRYSTALLIZATION
DEFORMATION
EPOXIDES
FABRICATION
FAILURES
GLASS
MECHANICAL PROPERTIES
MOISTURE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POLYCARBONATES
POLYMERS
RELAXATION
SORPTIVE PROPERTIES
STRESSES
SURFACE PROPERTIES
SURFACES
SWELLING