Síntese e caracterização de poliéster obtido a partir de norbixina e ácido gálico

Abstract

Polymers are used in the making of a large amount of materials due to the desirable properties they exhibit, such as low cost, high durability, ease of manufacture and recyclability. They are widely used as adhesives, lubricants, structural components of various products, such as aircraft components, in medicine they are used in medical implants and in drug delivery procedures, among other uses and diverse applications. This study aimed to obtain a polymeric material, a polyester synthesized from the natural product norbixin and gallic acid. The synthesized polymer was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Spectrophotometry in the Visible Ultraviolet Region (UV-Vis). Norbixin analysis showed that the extraction was effective. The FTIR spectrum of the polymer showed the intrinsic absorptions of ester, a functional group characteristic of the synthesized polyester, showing that the esterification reaction occurred satisfactorily. The TGA curves show the polymer has less thermal stability than norbixin up to approximately 427 oC. The DSC curves show that the polymer has a profile similar to norbixin and gallic acid, confirming the obtaining of the polyester. Vitreous also presented the transition (Tg) of the polymer at 192 °C, indicating that the polymer has thermoplastic characteristics. The absorption spectra in UV-Vis show absorptions related to the electronic transitions characteristic of carbonyl chromophores of acids, esters and C=C bonds, corroborating the results of TG and DSC and suggesting photoluminescent properties. XRD analysis shows that the polyester has mainly crystalline structure.