Natural oil based highly functional polyols as feedstock for rigid polyurethane foam thermal insulation

Abstract

High functional polyols were obtained from natural oil feedstock available in Northern Europe via a modification of established polyol synthesis method from epoxidized vegetable oil. Epoxy ring opening and subsequent transesterification of the glycerol backbone with different polyfunctional alcohols, such as diethylene glycol (DEG), triethanolamine (TEA) and diethanolamine (DEA), were used to obtain polyols with high reactivity and high functionality. Chemical structure of obtained polyols was studied by Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC) and the matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry. From GPC data average molecular weight (Mn), the weight average molecular weight (Mw), polydispersity index and average functionality (fn) of polyols were determined. The obtained polyols were characterized by high fn = 3.6–5.8 and acceptable by industry standards OH value of 471–635 mgKOH/g and were used to prepare rigid PU foam thermal insulation material. It was possible to develop rigid PU foam formulations without using additional catalysts, which could be a positive effect in case of fast curing systems. The produced rigid PU foam thermal insulation materials had up-to industry standard characteristics of closed cell content above 95%, the apparent density of ∼ 40 kg/m3 and thermal conductivity below 22.0 mW/m·K for the majority of developed materials.