Design and Control of Network Architecture in Radiation-Curable Toughened Semi-Interpenetrating Network Resin Systems
Final rept. May-Aug 1999
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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Several issues related to the development of a radiation-curable rubber-toughened epoxy resin are investigated by performing a statistical analysis of semi-interpenetrating polymer blend formulations. The statistical analysis provided predictions for branching coefficient, copolymer molecular weight, and rubber-to-network connectivity for the B-staged interpenetrating networks. These statistical metrics relate to the properties of thermally generated B-stage networks, prior to secondary network formation using radiation cure methods, such as electron beam or ultraviolet excitation. The components of these resins were described, and a procedure was developed to determine the exact weight fractions of each component that must be mixed together to achieve a desired branching coefficient and resin composition. Compositional variables include weight ratio of the two dimethacrylates, weight ratio of the two monoepoxides, and weight ratio of epoxides to dimethacrylates. Using the raw materials selected for this study, we determined that many network structures are not attainable. Specifically, it is not possible to prepare B-stage resins without the use of mono- or difunctional units, such as phenyl glycidyl ether PGE or methacrylated digicydyl ether of bisphenol A bisGMA. The possible formulations are determined, and a map is proposed showing the combinations of PGE and bisGMA content that are allowed for B-stage formation.
- Organic Chemistry
- Physical Chemistry