Estudo da modificação superficial de fibras de carbono por meio de tratamentos a plasma para o aumento da adesão na interface de compósitos fibra de carbono/PPS

Pós-graduação em Engenharia Mecânica - FEG

Capacidade de termoplastificação da guta-percha com diferentes conicidades

jObjective: The objective of this study was to evaluate the thermoplasticity of the gutta-percha cones used for root canal obturation: Dentsply convencional (Dentsply Ind. e Com., Petrópolis, RJ, Brazil), Dentsply 0.04, (Dentsply Ind. e Com., Petrópolis, RJ, Brazil), Antaeos 0.04 (VDW GmbH, Munich, Germany), ProTaper (Dentsply Ind. e Com., Petrópolis, RJ, Brazil) and Alfa 0.06 (VDW GmbH, Munich, Germany). Material and method: Specimens of each material (n = 10) were prepared after heating. After 24 hours were again heated to 70 °C and placed between two glass plates and subjected to a compression of 5 kg for 2 minutes. The scanned image of the groups before and after the compression was analyzed with the software Image Tool (UTHSCSA Image Tool for Windows version 3.0, San Antonio, TX, USA). The flow capacity of the different materials was determined by the difference between the initial and final area of each specimen. The results were submitted to ANOVA and Tukey test with significance level of 5%. Result: Among the material evaluated, the gutta-percha cones Alpha 0.06 and ProTaper presented more thermoplasticity than other groups (p < 0.05). The Dentsply gutta-percha presented thermoplasticity intermediate. The groups Dentsply 0.04 and 0.04 showed lower thermoplasticity after heating (p > 0.05). Conclusion: The gutta-percha present different property of thermoplasticity, which is important to selection of thermoplastic obturation techniques.

Otimização do processo de soldagem por resistência elétrica em compósitos PEI/fibras contínuas para aplicações aeronáuticas

Pós-graduação em Engenharia Mecânica - FEG

Vegetal fibers in polymeric composites: a review

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação dos parâmetros tempo, corrente e pressão na soldagem por resistência elétrica de compósitos PEI/fibras contínuas: influência na resistência mecânica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal degradation and lifetime estimation of poly(ether imide)/carbon fiber composites

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of water immersion and ultraviolet weathering on mechanical and viscoelastic properties of polyphenylene sulfide-carbon fiber composites

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Strategies to improve the mechanical properties of starch-based materials: plasticization and natural fibers reinforcement

Biodegradable polymers are starting to be introduced as raw materials in the food-packaging market. Nevertheless, their price is very high. Starch, a fully biodegradable and bioderived polymer is a very interesting alternative due to its very low price. However, the use of starch as the polymer matrix for the production of rigid food packaging, such as trays, is limited due to its poor mechanical properties, high hidrophilicity and high density. This work presents two strategies to overcome the poor mechanical properties of starch. First, the plasticization of starch with several amounts of glycerol to produce thermoplastic starch (TPS) and second, the production of biocomposites by reinforcing TPS with promising fibers, such as barley straw and grape waste. The mechanical properties obtained are compared with the values predicted by models used in the field of composites; law of mixtures, Kerner-Nielsen and Halpin-Tsai. To evaluate if the materials developed are suitable for the production of food-packaging trays, the TPS-based materials with better mechanical properties were compared with commercial grades of oil-based polymers, polypropylene (PP) and polyethylene-terphthalate (PET), and a biodegradable polymer, polylactic acid (PLA).

Estudo experimental do uso de rebolos convencionais na usinagem do aço VP-50 utilizado na retificação cilíndrica, por meio de diferentes métodos de lubri-refrigeração

Pós-graduação em Engenharia Mecânica - FEB

Compósitos preparados a partir de resíduo industrial de couro com elastômeros termoplásticos obtidos através de blendas de polietileno de baixa densidade e borracha natural

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)