Electron beam curing of epoxy resins by cationic polymerization

Conference · Sun Oct 01 04:00:00 EDT 1995

OSTI ID:634186

Janke, C J; Dorsey, G F ^[1]; Havens, S J ^[2]; Lopata, V J ^[3]

---

1. Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)
2. Oak Ridge Inst. for Science and Education, TN (United States)
3. Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada). Whiteshell Labs.

Preliminary investigations have determined that conventional epoxy resins can be cured at selectable temperatures with high glass transition temperatures (essentially the same as with thermal curing), while still exhibiting equivalent or comparable mechanical properties. A cationic photoinitiator at a concentration of 1--3 parts per hundred of the epoxy resin is required for this process. Gamma cell screening of cationic photoinitiators with bisphenol A, bisphenol F, and cycloaliphatic epoxies demonstrated that diaryliodonium salts of weakly nucleophilic anions such as hexafluoroantimonate are most effective. Diaryliodonium salts were also found to be most effective initiators for the cationic polymerization of epoxy resins when a high energy/power electron beam accelerator was used as the source of ionizing radiation. For example Dow Tactix 123 (bisphenol A epoxy) containing 3 phr (4-octyloxyphenyl)phenyliodonium hexafluoroantimonate was irradiated at a total dosage of 100 kGy. Glass transition temperature (tan delta) of the cured material as determined by dynamic mechanical analysis was 182 C as compared to 165 C thermally cured material.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 634186
• Report Number(s): ORNL/CP--94481; CONF-960310--; ON: DE98000320; BR: GB0106000
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CATALYSTS
COMPOSITE MATERIALS
CURING
ELECTRON BEAMS
EPOXIDES
POLYMERIZATION
TRANSITION TEMPERATURE