The effect of various rapeseed oil-based polyols on selected properties of flexible polyurethane foams

Abstract

Bio-polyols based on rapeseed oil were used to produce flexible polyurethane foams (FPURF). The bio-polyols were obtained on a laboratory and industrial scale with the two-step method involving epoxidation of double bonds in rapeseed oil and opening of oxirane rings with different alcohols, such as isopropanol (iP) and diethylene glycol (DEG). The impact of bio-polyols production scale on selected physical and mechanical properties of FPURF was analyzed. The applied bio-polyols differed slightly by hydroxyl number, functionality, and water content. It was found that the scale of bio-polyol production has no significant impact on FPURF properties such as apparent density, hardness, hysteresis, support factor, and resilience. However, it was observed, that the addition of the bio-polyol to polyurethane (PUR) formulation had the impact on the FPURF properties as compared to the reference foams that were not modified with the bio-polyols. Moreover, a continuous method was used to prepare FPURF samples modified with different rapeseed oil-based polyols. For this purpose mixing-dosing device with conveyor line was used to synthesize the foams. It was found that the replacement of petrochemical polyols with the bio-polyols resulted in lower reactivity of the modified for- mulations and the amount of catalysts had to be increased. Furthermore, the foams hysteresis, support factor, and hardness were higher, especially for foams modified with the bio-polyol that contained DEG in its structure. Moreover, the fatigue tests were performed and the results showed a beneficial effect of the bio-based polyols on the functional properties, a.o. support factor of flexible foams.