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Heat‐resistant epoxy‐boroxine foams for high temperature applications
Author(s) -
Chen H. H.,
Nixon A. C.
Publication year - 1965
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760050205
Subject(s) - epoxy , materials science , composite material , polystyrene , curing (chemistry) , polymer , heat resistance , amine gas treating , chemical engineering , organic chemistry , chemistry , engineering
Foams are produced by mixing an epoxy resin, a primary polyamine and a trialkoxyboroxine without applied heat. The reaction heat evolved, predominantly from the reaction between the boroxine and the amine, speeds up the gelation of the epoxy resin and simultaneously evaporates methanol, a by‐product, to form the foam, leading to the formation of a highly crosslinked polymer. A theory for the mechanism involves the chemical properties of intermediates, the basicity of the nitrogens, the acidity of the borons, and the mode of curing of the epoxy resin. The physical properties can be varied using different epoxies, amines and boroxines and different proportions. With a typical mixture, the foams produced have densities and thermal conductivities similar to polystyrene foam but have heat resistance up to 300°C. Adhesion to various substrates is excellent. Compression strengths are low but can be increased by the addition of fillers. The foams are self‐extinguishing. Potential applications and method of dispensing the foams are suggested.