COMPUTATIONAL STUDY AND CHARACTERIZATION OF POLYURETHANE FOAMS DEVELOPED TO BASED CANE MOLASSES

Abstract

In this research was studied the behavior of a polyurethane material synthesized by the partial replacement of PEG-400 for molasses at different compositions. It was observed in the IR spectra of the different samples the absence of the peak at 2268 cm characteristic of the group -NCO which allowed to deduce that the reaction proceeded satisfactorily between the diisocyanate and the different polyols, the characterization was performed using differential scanning calorimetry, electrical impedance and optical microscopy. In the DSC heating scans the endotherms corresponding to the glass transition temperature, Tg, with values of: 74, 64, 55 y 74 ºC, For substitution percentages of 10, 20, 30 y 40 % w/w respectively. For the same polyurethanes, the melting temperature, Tm, with values of: 153, 164, 175 y 179 ºC. The shift experienced by Tg and Tm has been associated with increased hard segments in the matrix as a result of the carbohydrates addition to the polymer chain. The impedance was measured in the range of 10 to 500,000 Hz at room temperature, finding significant variations in conductance depending on the composition of molasses, which is related with the energy gap between HOMO and LUMO, in addition to a significant shift in the point of dielectric relaxation. Optical microscopy revealed significant changes in morphology and size of the pores with average values approximate: 40, 53, 94 and 102.24 μm respectively, and a value of 134 μm for reference material. These variations in pore size have been attributed to the variation of reaction rate due to the decrease of the content of PEG-400 in the array.