In the present study, epoxidation and ozonolysis led to a decrease of 40.8 and 51.9 % in the degree of unsaturation of corn oil, respectively. Both products were initially characterized by Fourier transform infrared spectroscopy and 1 H-and 13 C-nuclear magnetic resonance spectroscopies. The heteronuclear single-quantum correlation spectroscopy (HSQC) analysis of the polyol obtained by epoxidation showed that carbinol hydrogen signals, located between 3.65 and 3.47 ppm, were correlated to carbon signals between 74.4 and 71.7 ppm. HSQC analysis of the polyol obtained by ozonolysis revealed these same chemical shifts at 3.64 and 62.9 ppm, respectively. Compared to pure corn oil, the differential scanning calorimetry of both corn oil-based polyols displayed the absence of any detectable melting peaks. However, the epoxidized derivative had a higher thermal stability than the ozonated sample, as shown by thermogravimetric analysis.
Poly(methy1 methacrylate-coethyleneglycol dimethacrylate) networks were synthesized with systematic variation in crosslinking density. The molecular weight between crosslinks (Me) was determined by equilibrium swelling measurements. The glass transition temperature was used to evaluate the effect of curing time and the degree of crosslinking on the networks. Flexural strength and impact resistance decreased with increasing h?, .
Castor oil (CO) is one of the most valuable oils, because of its characteristics and potential use in synthesis. A simple way to modify the castor oil structure is the transesterification reaction with an alcohol. Through this reaction, a renewable polyol could be produced and applied in the polyurethane industry. In this study, the transesterification was done by KOH catalysis following a Taguchi experimental design. The chosen alcohol was diethylene glycol (DEG) and the product components were estimated by GPC. This chromatographic technique allowed establishment of the most favorable conditions to produce monosubstituted DEG or disubstituted DEG. In the conditions suggested by the Taguchi design, the condition that favors monosubstituted DEG is 9:1 DEG:CO molar ratios, 200°C for 4 h and 0.5% KOH. This condition leads to approximately 75% monosubstituted DEG and 11% disubstituted DEG in a mixture with the remaining acylglycerols. The hydroxyl value of this product is 407, a high value for a product with a relatively low molecular weight. These characteristics suggest that it can be used as a polyol for polyurethanes.
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