Radiopaque epoxy resins

Abstract

AbstractTransparent, X‐ray contrast (radiopaque) epoxy resins were obtained by dissolving up to 25 wt % triphenylbismuth in the commercial epoxy resin prepolymers EPON‐815, DER‐330, DER‐383, and DEN‐431 which were then hardened with diethylenetriamine. The radiopacities of the mixtures were found to be proportional to the molar concentration of the radiopaque additive. The systems follow the relationship, R = Ro + (Ra − Ro) Va Ma where R, Ro, and Ra are the radiopacities of the mixture, the pure epoxy resin, and triphenylbismuth, respectively (expressed in mm aluminum/mm resin); Ma and Va denote the molar concentration and molar volume of the bismuth compound. Ra for triphenylbismuth was found to be 7.4 ± 0.2 mm Al/mm resin; the average value of Ro for the four epoxies equals 0.16 ± 0.1 mm Al/mm resin. The amount of amine required to harden the radiopaque resins was far less for the epoxy novolac resin DEN‐431 than for the three bisphenol‐A based epoxies. The concentration of triphenylbismuth required to impart a radiopacity equivalent to that of aluminum measures 14.6 wt % in EPON‐815, 14.8 wt % in DER‐330, 14.9 wt % in DER‐383, and 15.9 wt % in DEN‐431. The radiopaque resins remain transparent indefinitely, even when exposed to water. © 1995 John Wiley & Sons, Inc.