Síntese e caracterização de poliéster obtido a partir do produto natural norbixina e propileno glicol

Abstract

Polyesters belong to a class of polymers often employed in the manufacture of fibers and membranes, including fabrics can be made, plastics, packaging and more enhanced applications depending on their properties, can be used as biomaterials. The work lectured aims to synthesize and characterize a new polymeric material, a polyester obtained from natural product norbixin, substance extracted from annatto (Bixa Orellana L.), and propylene glycol, polyol widely used in organic synthesis. The synthesis was performed through a classical polyesterification reaction (in this case, a reaction between a dicarboxylic acid with a diol), performed in an open system under heating and stirring. After 50 minutes and temperature 130 °C, is added as catalyst, the cobalt acetate. Maintaining the constant temperature and elapsed over about 10 minutes, the reaction mixture began to change phase, starting to introduce plastic characteristics with some degree of viscosity. After completion of polymerization, the material was naturally cooled to room temperature, where it has become hardened with cracked appearance. Was executed all necessary preparation of the polymeric material for the study of their structural, thermal and morphological properties through characterization techniques: Infrared Spectroscopy Fourier Transform (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Microscopy Scanning electron microscopy (MEV). The analyzes of the structural composition of FTIR spectroscopy showed the appearance of the typical bands of ester carbonyl (1735 cm–1) and reduced absorption intensity of stretches O–H, which excels a decrease in character hydroxyl groups removed in the polycondensation reaction. The thermal characterization curves (DSC and TGA) showed that the synthesized material shows phase transitions appreciable values for polymeric materials, especially amorphous thermoplastic polymers with trends. The morphology of the polyester shown in the SEM analysis showed small oligomers blocks immersed in a large flat polymeric matrix, related to their linear polymeric chain with the presence of a large amorphous phase. The results obtained from these analyzes were satisfactory, indicating that there was formation of a new polymeric structure with well defined characteristics and distinct from forming monomers, ensuring consistency and reproducibility of propylene polinorbixinato (PNP) synthesis method.