Fifty vegetable oil-based polyols were characterized in terms of their hydroxyl number and their potential of replacing up to 50% of the petroleum-based polyol in waterborne rigid polyurethane foam applications was evaluated. Polyurethane foams were prepared by reacting isocyanates with polyols containing 50% of vegetable oilbased polyols and 50% of petroleum-based polyol and their thermal conductivity, density, and compressive strength were determined. The vegetable oil-based polyols included epoxidized soybean oil reacted with acetol, commercial soybean oil polyols (soyoils), polyols derived from epoxidized soybean oil and diglycerides, etc. Most of the foams made with polyols containing 50% of vegetable oil-based polyols were inferior to foams made from 100% petroleum-based polyol. However, foams made with polyols containing 50% hydroxy soybean oil, epoxidized soybean oil reacted with acetol, and oxidized epoxidized diglyceride of soybean oil not only had superior thermal conductivity, but also better density and compressive strength properties than had foams made from 100% petroleum polyol. Although the epoxidized soybean oil did not have any hydroxyl functional group to react with isocyanate, when used in 50 : 50 blend with the petroleum-based polyol the resulting polyurethane foams had density versus compressive properties similar to polyurethane foams made from 100% petroleum-based polyol. The density and compressive strength of foams were affected by the hydroxyl number of polyols, but the thermal conductivity of foams was not.

A screening study was conducted to identify a catalyst that promotes epoxy ring opening of full epoxidized soybean oil (ESBO) avoiding side reactions at low concentration and temperature. Six catalysts different catalyst: formic acid, phosphoric acid, POLYCAT V R 5, p-toluenesulfonic acid monohydrate, POLYCAT V R SA-1, and DABCO V R BL17 were evaluated in terms of acid number, oxirane oxygen content, and color analyses. p-Toluenesulfonic acid shows a particular behavior that promotes the reaction resulting in a maximum oxirane oxygen content reduction; low acid number and color index compare to the others catalyst. To create an alkoxy hydroxy ESBO molecule, ESBO was combined with methanol and ethylene glycol using 0.5% by wt of p-toluenesulfonic acid at 130, 150, and 170 C for different reaction times. Optimal conditions for oxirane ring opening by alcoholysis reaction were determined varying temperatures and reaction times. FTIR spectrum confirmed the emergence of hydroxyl groups in the alkoxy hydroxy ESBO polyol sample. The polyol sample G was characterized in terms of its hydroxyl number and its potential of replacing up from 50-100% of the petroleum-based polyol in waterborne rigid polyurethane foam application. All polyurethanes foams were evaluated to determine their thermal conductivity, density, and compressive strength properties.

Both rigid and flexible water-blown polyurethane foams were made by replacing 0-50% of Voranol 1 490 for rigid foams and Voranol 1 4701 for flexible foams in the B-side of foam formulation by epoxidized soybean oil. For rigid water-blown polyurethane foams, density, compressive strength, and thermal conductivity were measured. Although there were no significant changes in density, compressive strength decreased and thermal conductivity decreased first and then increased with increasing epoxidized soybean oil. For flexible water-blown polyurethane foams, density, 50% compression force deflection, 50% constant force deflection, and resilience of foams were measured. Density decreased first and then increased, no changes in 50% compression force deflection first and then increased, increasing 50% constant force deflection, and decreasing resilience with increase in epoxidized soybean oil. It appears that up to 20% of Voranol 1 490 could be replaced by epoxidized soybean oil in rigid polyurethane foams. When replacing up to 20% of Voranol 1 4701 by epoxidized soybean oil in flexible polyurethane foams, density and 50% compression deflection properties were similar or better than control, but resilience and 50% constant deflection compression properties were inferior.

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Water-blown flexible polyurethane foams and molded plastic films were made by replacing 0 to 50% of Voranol V V R 4701 in the B-side of foam and plastic film formulation by epoxidized soybean oil (ESBO). Physical properties of foams including density, 50% compression force deflection (CFD), 50% constant deflection compression (CDC), and resilience were determined. A dynamic mechanical spectrometer (DMS) and a differential scanning calorimeter (DSC) were used to characterize the hard segment (HS) and soft segment (SS) ratio and thermal properties of plastic. Various functional groups in both flexible polyurethane foam and plastic film were characterized using Fourier transform-infrared spectroscopy with attenuated total reflectance (FTIR-ATR). When increasing the ESBO content, both density and 50% CFD of water-blown polyurethane foams decreased first, then increased. On the other hand, the 50% CDC and resilience of foams showed a sharp increase and decrease, respectively. When increasing the ESBO content, the peak of tan d in DMS analysis and Dc p in DSC analysis of plastic films both decreased indicating the hard segment increased and the soft segment decreased in plastic film, respectively. The FTIR-ATR results also show the hydrogen-bonded urethane group increased in plastic films with increasing ESBO content.

ABSTRACT:The study investigated an approach to incorporate modified epoxidized soy-based vegetable oil polyol as a replacement for petroleum-based polyether polyol and to substantially reduce the isocyanate loading in the rigid foam formulation. Noncatalytic polymerization of epoxidized bodied soybean oil and ethylene glycol (EG) was carried out in a closed batch reaction. Cleavage of the oxirane rings and hydroxyl group attachment at optimum conditions provided the desired polyol products. The polyols were characterized based on its hydroxyl numbers, acidity, viscosity, iodine number, and Gardner color index for quality purposes. Reactions of oxirane ring and EG were verified by spectroscopic FTIR. Crosslinking performance was evaluated by extractability analysis on the polyurethane (PU) elastomer wafers. Rigid foaming performed at 50 and 75% petroleum-based polyether polyol replacements have shown excellent thermoinsulating and mechanical properties compared with epoxidized soybean oil (ESBO) alone or petroleum-based polyether polyol alone. A reduction of up to 8% of the polymeric diphenylmethane diisocyanate was achieved using the synthesized ESBO-EG-based polyols. A higher average functionality polyol is key component to the reduction of isocyanate in PU synthesis.

In the absence of polymerization, soy-based polyols tend to have inadequate hydroxyl equivalent molecular weights for many critical urethane applications. In this article, the polymerization (bodying) of soybean oil is presented as an effective method to increase the molecular weight of soy-based polyols. When bodying is combined with reaction steps for alcohol addition and acid reduction, soy-based polyols suitable for urethane applications can be synthesized. Two different heat-polymerization approaches, catalyzed-and noncatalyzed-bodied soybean oil (BSBO) were evaluated in continuous and batch processing. The catalyzed-BSBO has lower iodine numbers and high viscosities than the noncatalyzed-BSBO. This approach represents one of the least-costly means to increase the hydroxyl equivalent weights of soy-based polyols.

To explore the potential of isocyanate usage reduction, water-blown rigid polyurethane foams were made by replacing 0, 20, and 50% of Voranoll V R 490 in the B-side of the foam formulation by epoxidized soybean oil (ESBO) with an isocyanate index ranging from 50 to 110. The compressive strength, density, and thermal conductivity of foams were measured. The foam surface temperature was monitored before and throughout the foaming reaction as an indirect indication of the foaming temperature. Increasing ESBO replacement and/or decreasing isocyanate index decreased the foam's compressive strength. The density of the foam decreased while decreasing the isocyanate index to 60. Further decrease in isocyanate index resulted in foam shrinkage causing a sharp increase in the foam density. The thermal conductivity of foams increased while decreasing the isocyanate index and increasing the ESBO replacement. Mathematical models for predicting rigid polyurethane foam density, compressive strength, and thermal conductivity were established and validated. Similar to compressive strength, the foaming temperature decreased while decreasing the isocyanate index and increasing the ESBO replacement. Because of the lower reactivity of ESBO with isocyanate, the rate of foaming temperature decrease with decreasing isocyanate index was in the order of 0% > 20% > 50% ESBO replacement.