investigation the effects of temperature & oxygen on the epoxy resin yellowing during synthesis

Epoxy resins are an important class of polymeric materials applied in a broad range of products as adhesives, coatings, and moldings. understanding what causes a yellowing in the epoxy resin production is of importance for applications like coatings and stone conservation. the syntheses of dgeba epoxy resin at different atmosphere and drying temperatures showed that oxidation occur during the reaction in air cause the resin to be yellow. drying at 80oc led to a clear and colorless resin but at 120oc led to a yellow resin. ft-ir spectrum confirms formation of dgeba. the color of the resin can be associated with the changes in ft-ir, in particular with the formation of carbonyl and unsaturated structures. the band at 1719 cm-1 lies in the region characterized by six membered ring ketones, conjugated and aryl aldehyde structures produced by thermal degradation. all of these results showed that thermal degradation can occur even at low temperatures and drying of resin during synthesis should be done at minimum time and temperatures to take a clear colorless resin. the results also showed that all of four products have same eews in the range of 195-200 and different atmosphere and drying temperatures had no major effect on eew of the products.