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E. Hałasa

Radiolysis of cured and uncured bisphenol A–epoxy resins

Polimery 2000, No 1, 1


DOI: dx.doi.org/10.14314/polimery.2000.001


Summary

A review with 28 references covering the resistance of cured and uncured bisphenol A–epoxy resins to ionizing radiation and the irra­diation-effected changes in the physicochemical properties of the uncured re­sins in relation to molecular weight. Medium-M (900–1600, Table 2) resins irradiated with doses of 2 MJ/kg become infusible; low-M (500) resins requi­re higher doses; higher-M (2000) resins do not crosslink even at 20 MJ/kg and their softening point remains unaffected. With the epoxy and the hy­droxyl groups present in the resin in practically equal proportions, crosslink­ing proceeds easily. Low-M epoxies with a considerable excess of epoxy over hydroxyl groups, were crosslinked when irradiated with doses of 3 MJ/kg; the epoxy groups were isomerized and underwent destruction (eqns. 1–9). The resistance of epoxy materials to radiolysis is substantially related to the nature of curing agents and curing conditions. Arthydride- or aromatic ami­ne-cured resins are most resistant to irradiation (1–10 MJ/kg); aliphatic amine-cured resins are least resistant (0.01–0.1 MJ/kg). Resistance to irra­diation is directly related to thermal resistance. Dibutyl phthalate and other phthalate type diluents do not suppress the resistance of resins to irradia­tion. The dielectric properties of the electroinsulating laminates based on precondensed epoxy and novolak resins and glass fibers, remain unaffected upon absorption of 0.1 to 1 MJ/kg. Protective epoxy coatings made of com­positions involving solvents or no solvents, resist doses of up to 0.1 MJ/kg. Solventless coatings exhibit good sorptive-desorptive properties toward ra­dio-elements (cesium, strontium, plutonium, uranium).


Keywords: bisphenol A–epoxy resins, effect of ionizing radiation, crosslink­ing, mechanical and dielectric properties, sorption and desorption of radio­active elements, applications

E. Hałasa (512 KB)
Radiolysis of cured and uncured bisphenol A–epoxy resins