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Title: Electron beam curing of epoxy resins by cationic polymerization

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.
Authors:
;  [1] ;  [2] ;  [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.
Publication Date:
OSTI Identifier:
634186
Report Number(s):
ORNL/CP--94481; CONF-960310--
ON: DE98000320; BR: GB0106000; TRN: AHC2DT01%%197
DOE Contract Number:
AC05-96OR22464
Resource Type:
Conference
Resource Relation:
Conference: 41. international symposium of the Society for the Advancement of Material and Process Engineering and exhibition: materials and processes challenges - aging systems, affordability, alternative applications, Anaheim, CA (United States), 25-28 Mar 1996; Other Information: PBD: Oct 1995
Research Org:
Oak Ridge National Lab., TN (United States)
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; EPOXIDES; CURING; ELECTRON BEAMS; POLYMERIZATION; COMPOSITE MATERIALS; CATALYSTS; TRANSITION TEMPERATURE