https://repositorio.ufpb.br/jspui/handle/123456789/2402 2026-04-16T22:06:29Z https://repositorio.ufpb.br/jspui/handle/123456789/28047 Título: Comparação entre modelos experimentais de interação química de polivinilpirrolidona e quitosana Autor(es): Ferreira, Jacyara Florencio Orientador: Cardoso, Márcio José Batista Abstract: The development of dressings based on renewable sources is gaining more and more space in the medical and biomedical field, as in addition to being a biodegradable alternative, it is a specific and effective process for the treatment or repair of organs, tissues and functions of the human body. . Due to their physical-chemical, mechanical and biological properties, dressings based on renewable sources are a promising alternative for several applications, such as, for example, those caused by radiation. Thus, polyvinylpyrrolidone and chitosan biopolymers have biological and physical-chemical properties, with great conversion in the treatment of skin wounds, which can be individualized. Therefore, analyzing the chemical interaction behavior between these polymeric biomaterials is necessary to improve and/or acquire new properties. The objective of this work was to evaluate the quiet chemistry of PVP/Chitosan mixtures, through modeling using a linear model and compare with experimental data obtained, using experimental optimization by the response surface methodology using the Box-Behnken model, from Fourier transform infrared spectroscopy (FTIR) results. We conclude that qualitatively the models show a reduction in the interaction area with the increase in the proportion of chitosan, favoring hydrogen bonds, and that the experimental model presents a better statistical adjustment to characterize the miscibility of the blends from the proposed mathematical model. Editor: Universidade Federal da Paraíba Tipo: TCC 2023-06-13T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/25227 Título: Estudo do efeito da dopagem da terra-rara európio na estrutura, morfologia e nas propriedades magnéticas da matriz semicondutora ZnO visando obter um Semicondutor Magnético Diluído (SMD) Autor(es): Maia, Daniel Barrêto Orientador: Torquato, Ramon Alves Abstract: The search for the development of increasingly sophisticated semiconductor devices, with greater efficiency and processing speed, has induced the electronic industry to increase the number of components that compose it and seek to miniaturize them. However, limits have been found in relation to the quantity and size of these components. In this context, spintronic technology based on the control and manipulation of the electron spin emerges, making it possible to use the ability to process data and to store informations simultaneously, obtaining greater efficiency, higher data processing speed and lower energy consumption. This technology can be achieved by means of the Diluted Magnetic Semiconductors (DMS), with zinc oxide (ZnO) being a promising candidate for its production, since it exhibits ferromagnetic behavior above room temperature through the doping of transition metal ions or rare earths in its structure, such as the Europium (Eu), which has stood out due to the good magnetic moment (≈ 6,9 μB). In this work, a ZnO based DMS doped with Eu3+ ions at concentrations of 0.05 and 0.1 moles was synthesized by combustion reaction. The samples were sintered at 1100°C for 30 minutes. In order to evaluate the effect of europion concentration and sintering on the structure, band gap, magnetic properties and morphology of ZnO, the samples were analysed before and after sintering by X-ray Diffraction (XRD), Spectroscopy in the Ultraviolet and Visible region (Uv-Vis), Vibrant Sample Magnetomy (VSM) and Scanning Electron Microscopy (SEM). From the results obtained, it was found that there was formation of second phase (Eu2O3), with the exception of the sample in the condition of powder doped with 0.05 mols of europium. It was observed that all samples, before and after sintering, exhibited band gap values within the semiconductor range and ferromagnetism at room temperature. In addition, it was possible to visualize that the morphology of the samples is significantly altered with the increase of the europion concentration in the system. Editor: Universidade Federal da Paraíba Tipo: TCC 2019-09-27T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/25173 Título: Cristalização e morfologia dos sistemas PBT/PCL e PC/PCL Autor(es): Almeida, Debora Evelyn de Oliveira Orientador: Wellen, Renate Maria Ramos Abstract: Polycarbonate (PC) is an amorphous thermoplastic very known for its excellent properties, such as high transparency and good dimensional stability. However, it has some drawbacks which limit its use in several applications, such as notch sensitivity; these can be solved by mixing PC with polymers which have a higher plasticizer action. Polybuthylene Terephthalate (PBT), is a semi-crystalline polymer that has good thermal stability, excellent processing properties and fast crystallization rate. Also, some of its undesired properties can be improved by mixing with other polymers. Therefore, in this work, blends of these polymers with poly (ε-caprolactone) (PCL), which has macromolecular regularity becoming highly crystallizable and thus improving its mechanical properties. Based on above mentioned, the objective of this work was producing PBT/PCL and PC/PCL blends, evaluating crystallization, observing the morphology and studying their toughening. The blends were prepared in an internal Haake Rheomix 600 laboratory mixer. The morphologies and fracture behavior were investigated by scanning electron microscopy (SEM), through this technique it was also possible to analyze the effect of PCL toughening when added to PC. For PBT/PCL system, the melting and crystallization phase transitions were studied by differential scanning calorimetry (DSC), and its thermal stability was evaluated by Thermogravimetry (TG). No degradation signs were verified during blends processing, and these presented positive compatibility. It has been found that PC toughening can be achieved upon PCL addition, while the crystallinity and properties of PBT/PCL blends can be controlled by the heating/cooling rates as well as through PCL addition. Editor: Universidade Federal da Paraíba Tipo: TCC 2019-05-02T00:00:00Z https://repositorio.ufpb.br/jspui/handle/123456789/25171 Título: Avaliação de compósito de PEAD com resíduo de concha de molusco calcinado e modificado com silano Autor(es): Chagas, Thaís Fernandes das Orientador: Silva, Lucineide Balbino da Abstract: Polymers are increasingly being used by man as more practical, lightweight, low cost materials. Studies are being carried out with the purpose of improving the properties of these polymers, generating benefits in all areas. The best way to modify the properties of the polymers is through composite materials. An example of this is the addition of calcium carbonate (CaCO3) from mollusk shells as reinforcements. This mixture alone does not allow a good union of these elements, necessitating the use of coupling agents to ensure adhesion and improve properties. This work aims to evaluate high density polyethylene (HDPE) polymer matrix composites with 20% calcined shell reinforcement (CC) and with (CC) modified with APTS (3-aminopropyltriethoxy silane). HDPE and HDPE composites (HDPE/CC) and treated with Silane (HDPE/CC/Si) and treated at 100 °C (HDPE/CC/Si/T) were mixed using the Rheometer of Haake torque and molded in a hydraulic press. In the molding of the HDPE / DC composite, it was necessary to make a modification in the process conditions due to the difficulties of molding them, since they had regions with porosity and voids well accented, seen with the naked eye. This can be verified with the flowability that was the lowest, around 4,116g/10min, while the PEAD/CC/Si composite was 6.272 g/10min, which had a good impression. By the Thermogravimetric analysis it was possible to increase the initial degradation temperature of the pure HDPE with the addition of the shell, from 352 to 380 °C. In the Scanning Electron Microscopy (SEM) it was possible to visualize a good interface caused by the addition of Silane in the modification of the CC (HDPE/CC/Si) and this led to an increase in the mechanical properties under flexion. Therefore, the addition of the calcined shell of silane treated mollusc in the HDPE polymer matrix led to improvements in thermal and mechanical properties. Editor: Universidade Federal da Paraíba Tipo: TCC 2019-05-10T00:00:00Z