POLYURETHANES FROM SOYBEAN OIL-BASED POLYOLS WITH MIXED PRIMARY AND SECONDARY HYDROXYLS

摘要

Soybean oil was converted by epoxidation and hydroformylation to polyols with varying ratio of secondary and primary hydroxyl groups while keeping hydroxyl content approximately constant at about 200 mg KOH/g. Polyols with secondary groups were solid at room temperature. Their consistence changed gradually to liquids as the content of hydroformylated OH groups increased. Reactivity of polyols with diisocyanates was studied by viscosity increase with time. Glass transition of resulting polyurethanes with the same functionality of polyols varied linearly with the content of primary groups being lower for the higher content of hydroformylated hydroxyls. This was explained by the larger molecular weight of network chains, Mc, of hydroformylated polyols due to extra carbon atoms introduced by the process. The effect of crosslinking density, primary hydroxyl content and polyol reactivity on properties is discussed.