The Resins

Abstract

Epoxy resins were tested quite early on in the development of EM embedding media as alternatives to methacrylate (Maaløe and Birch-Andersen, 1956; Glauert et al, 1956; Glauert and Glauert, 1958; Luft, 1961; Glauert, 1965, 1975). The epoxy resins gave uniform curing, and were found to be beam-stable. Uncrosslinked methacrylate is only two-dimensionally bonded and is rapidly destroyed in the electron beam. It is also prone to shrinkage, sometimes uneven, causing shearing and “polymerisation damage” (Pease, 1964; Glauert, 1965, 1975). By the time these problems were addressed the epoxy resins, which had no such problems, were firmly established. The history and development of epoxy resins and the other group of beam-stable, highly crosslinked resins, the polyesters, is well documented elsewhere (Glauert, 1965,1975,1991).