Síntese e caracterização de poliéster obtido a partir do óleo de mamona modificado, glicerol e norbixina

Abstract

Polyesters have gained significant space in the automotive industry, engineering plastics, electro-electronics, adhesives, films, varnish, paints, in the textile industry, etc. This rise is directly related to the properties that these materials present as: thermal resistance, chemical resistance, stiffness, processability, moldability, crystallization velocity among others. The synthesis and characterization of a new polymer material, a polyester obtained from norbixin, a substance extracted from annatto (Bixa Orellana L.), glycerol and castor oil were carried out in this work. Norbixin was extracted from the annatto seeds by means of an alkaline extraction. Castor oil underwent a transesterification process to obtain the methyl esters. From the methyl esters, reactions were made with glycerol in order to synthesize monoacyglycerols (MAG), a technique called glycerolysis. Following a wash-drying process, monoacyglycerols were used in the production of a new polymer material from the polyesterification reaction (in this case, a reaction between a dicarboxylic acid (norbixin) with a diol (monoacyglycerol) and a triol (glycerol ), Performed under open system under heating at 160 °C and constant stirring. The catalyst used was cobalt acetate. The characterization of the raw materials as well as the synthesized polyester were performed using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and X Rays Diffraction (XRD). The analysis of structural composition of FTIR spectroscopy showed the appearance of typical bands of carbonyl (1733 cm -1) and C-O in 1174 cm -1 of ester for the polymer synthesized through the polycondensation reaction. The appearance of a band at 1630 cm-1 gives indications that there was reaction and formation of the product, since it is believed that this band comes from norbixin. The thermal characterization curves (TG and DSC) showed a decomposition temperature increase for the polymer in relation to the norbixin carotenoid. X ray diffraction of the polyester sample revealed curves with broad halos characteristic of an amorphous material. scanning electron microscopy analysis showed well differentiated micrographs between norbixin and polyester, where the latter showed a strong tendency of amorphous structure. The results obtained evidenced the formation of a new polymer structure, with well defined and distinct characteristics of the forming monomers, ensuring consistency and reproducibility of the synthesis method of said polymeric material