Prepolymers, Epon

Distribution of molecular weights in the commercial resins. Gel permeation chromatography (GPC) indicated that the liquid and semi-solid prepolymers (Epon 825, 828, and 834) were composed of... 

Materials. The following Epon prepolymers (Shell Chemical Company) were used Epons 825, 828, 834 (all liquid to semisolid) and 1001, 1002, and 1004 (all solids). Approximate compositions (degree of polymerization) were determined by gel permeation chromatography. Bimodal blends were made by mixing Epon 825 with Epon 1004, as shown in Table 1. Sample preparation and the method of curing have been described in the preceding paper (29). 

In this study, the imperfection of the networks was varied by varying the stoichiometry of an Epon 828-methylene dianiline system. Related studies of morphology, other properties, and creep as a function of molecular weight and distribution of the prepolymer are described elsewhere (9-13). 

Two network systans were prepared (l) Epon 828/MDA networks, in which the reactant ratios were varied and (2) stoichiometric Epon resin/DDS networks incorporating variations in the prepolymer %. The more latent amine DDS was used for curing the... 

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