The effect of poly(oxyethyelene)diols on the synthesis and properties of a bisphenol-A based liquid epoxy resin
Polimery 1998, No 11-12, 673
Catalytic effect of poly(oxyethylene)diols (PEGs) was studied in the reaction of bisphenol A with epichlorohydrin and sodium hydroxide [eqns. (1) and (2)] to yield a mixture of diglycidyl ether of bisphenol A and its low-molecular-weight oligomers (bisphenol A based liquid epoxy resin). PEG (Mn = 150—4500) was used. The effect of Mn and concentration of PEG (0.0073—0.22 mol of -OCH2CH2- groups per 1 mol of -OH groups in bisphenol A) and the mixing rate (96—500 rpm) on the epoxy number (LEP), color, hydrolyzable chlorine content (Clh), stability at elevated temperature, viscosity, and resin gell time as well as the effect of 8-hours heating at 200°C on LEP, color and viscosity were examined. Analysis of the aqueous chase composition allowed to follow the pathway of PEG in the course of the synthesis of the resin. PEG was found to give rise to increased LEP, enhanced stability at elevated temperatures, prolonged gell time, and also to reduced consumption of epichlorohydrin (by 7%) and NaOH (by 7%) in the synthesis. The final product and the aqueous phase contained ca. 10% and 90% of PEG, resp. COD data showed the waste waters from the PEG-using synthesis to contain 14% more organics than those from syntheses without PEG.
Keywords: bisphenol A based liquid epoxy resin, poly(oxyethylene)diols, synthesis of bisphenol A based liquid epoxy resin