Funcionalização da poli(Ɛ-caprolactona) com anidrido maleico: otimização das condições reacionais por planejamento fatorial.

Abstract

In this work, the functionalisation of PCL with anhydrous malic acid (MA) was carried out in order to improve the compatibility of polymer blends. Since the grafting reaction aims to overcome the low surface energy between polymers, using a 2³ factorial design. The work was divided into two parts: In the first part, the synthesized functionalised polymers were run in an internal mixer and a double screw co-rotating extruder, with dicumyl peroxide (DCP) as a primer in order to accelerate the reaction of using the conventional method of initiation of grafting reactions, that is, initiation by thermal decomposition of a peroxide and, with the maleic anhydride (MA) as a functional group. In the second part of the work, the characterization of these functionalized polymers was carried out, in order to verify the grafting of the functional groups MA in the main chain of PCL. The percentage of grafted maleic anhydride (% gMA) was obtained by titration using the purified functionalized polymer. After purification of the functionalized polymers, the following characterizations were performed: Fourier Transform Infrared Espectroscopy (FTIR), Size Exclusion Chromatography (SEC), Nuclear Magnetic Resonance (NMR), Intrinsic Viscosity by the Ubbelohde assay, Rheometria of Torque and X-Ray Diffraction (XRD). It was observed that an increase in primer concentration increased the percentage of maleic anhydride grafted, resulting in a reduction in the molar mass of the functionalized polymer. The MA variable showed to be significant in the grafting reaction, as seen through a statistical program, using 0.3 and 1.0% DCP. On the other hand, the increase in MA concentration resulted in a decrease in the intrinsic viscosity of the functionalized polymers. The most efficient process was for the functionalized polymers in the extruder where the compositions with 2.5% MA and 1.0% DCP synthesized at 110 ° C and 2.5% MA and 0.3% DCP synthesized at 160 ° C showed 45 and 60% grafting efficiency, respectively.