Fernando Gomes de Souza Junior

Estudo das propriedades mecânicas e elétricas de fibras de curauá modificada com polianilina

Natural fibers have been employed as reinforcement filler in composite materials for the automobile industry. Among the natural fibers, the curaua fiber is promising due to its high mechanical resistance associated with low density values. In this work curaua fibers are chemically modified by a conducting polyaniline coating, with the aim of using this new conductive composite as pressure sensors. The composite material obtained was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) and optical microscopy. The results demonstrated that the methodology adopted was efficient in forming a partial, but effective, coating of the fiber, thus leading to conducting paths along the whole fiber. The electro-mechanical properties of the fibers were also evaluated and the composites have potential for low cost pressure sensors. Furthermore, the modified fibers had good thermal stability and the partial coating allows the composite to be naturally degraded as an environmentally-friendly material.

Influence of PLGA and PLGA-PEG on the dissolution profile of oxaliplatin

Oxaliplatin was inserted into polymeric matrices aiming to study the interaction of this drug with these polymers and its capability to diffuse to the environment. Tested polymers were: (1) polyethylene glycol (PEG), (2) poly(lactic-co-glycolic acid) (PLGA), and (3) a copolymer of them (PLGA-PEG). The latter two were synthesized by us using polycondensation in bulk. Oxaliplatin was included in the matrices by the melt mixing process followed by casting. Fourier tran sform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and X-ray diffraction (DRX) studies of the polymers were performed proving the obtaining of the desired materials. In addition, the interaction between drug and matrices and the release profile of the oxaliplatin from these matrices were analyzed. Among them, PEG did not control the oxaliplatin release. In turn, PLGA and PLGA-PEG present drug release profiles quite similar. Oxaliplatin was completely released from PLGA and PLGA-PEG in 5 hours, by a relaxation mechanism. There was no evidence of oxaliplatin interaction with the different polymers. In addition, as the PEG improves the biocompatibility and biomasking, obtained results prove the obtaining of a drug release system, which allowed the total use of the drug improving the cancer treatment and even the welfare of the patients.