Synthesis and characterization of bio-polyurethanes prepared using certain bio-based polyols

Abstract

Vegetable oils are considered to have huge potential as materials that can be used in the synthesis of high quality products such as, polyurethanes and poly (ether urethanes) etc. A series of bio-based triglyceride vegetable oils such as Azadirachta indica (neem oil), Jatropha curcas (jatropha oil) are used to prepare high molecular weight polyurethanes (PU’s). These are prepared by reactions involving polyols synthesized from neem and jatropha oil using aromatic diisocyanate. The cross-linking of the polyol and polyurethane structures is characterized by Fourier Transform Spectroscopy (FT-IR), Proton Nuclear Resonance Spectroscopy (1H NMR) and 13C Nuclear Resonance Spectroscopy (13C NMR). The effect of cross-linking on the polyols and chain extender density of polyurethane (PUs) molecular weight is determined by the Gel Permeation Chromatography (GPC). The power law model is used to calcuate the viscosity of the polyols characterized by Rheometry and flow rate of the polyols. The incorporation of the chain extender toluene diisocyanate (TDI) in polyurethane significantly improves the thermal properties along with the different weight loss in various temperature were characterized by thermogravimetry analysis (TGA). The thermal degradation and kinetic parameters such as entropy change, free energy change, apparent activation energy can be calculated using the Freeman-Carolls method to study the biodegradability of the polyurethanes(PUs).