Resumo O presente trabalho visa apresentar resultados da aplicação de uma resina epóxi bisfenólica (DGEBF) à base de nanopartículas de sílica (RN) e comparar suas propriedades com a resina convencional de referência epóxi bisfenólica (DGEBA) (RE), atualmente utilizada. Neste sentido fabricaram-se protótipos de barras estatórica, destinadas a hidrogeradores, através do sistema VPI (Vácuo-Pressão-Impregnação) e avaliaram-se as propriedades elétricas pelas técnicas de fator de dissipação e envelhecimento acelerado. Dentre os resultados para as resinas observou-se que: (i) o fator de dissipação e de envelhecimento são praticamente os mesmos para ambas as resinas; (ii) o valor de tip-up resultaram em 0,014% para RE e 0,020% para a resina RN e (iii) a estimativa do tempo de vida útil esta em cerca de 40 anos, o que é aplicável para a maioria das aplicações industriais. Neste sentido sugere-se que a resina RN pode ser uma alternativa a resina RE, com um desempenho elétrico equivalente.

Abstract The present work aims to present the results of an application of a bisphenolic epoxy resin (DGEBF) containing silica nanoparticles (RN) and compare its properties with a bisphenolic epoxy resin (DGEBA) (RE), currently used. In this context, prototype stator bars for hydrogenerators were manufactured, according to the VPI (Vacuum-Pressure-Impregnation) system and their electrical properties with the tests of dissipation factor and voltage endurance. Within the results for the resins it was observed that: (i) dissipation factor and voltage endurance are practically the same for both resins; (ii) the resulting values of tip-up were 0.014% for RE and 0.020% for RN resin and (iii) the estimating of the life-time is about 40 years, what is suitable for most industrial applications. In this sense it is suggested that the RN resin can be an alternative to the RE resin, with an equivalent electrical performance.

Biomaterials (composites and blends) play a major role in the health of modern society. This paper reports on the preparation and characterization of polyvinylidene fluoride (PVDF) and hydroxyapatite (HAP) composites, analyzing the incorporation of HAP in PVDF and investigating their mechanical properties and cytotoxicity (biocompatibility) for use in bone restoration and filling. The material was prepared in film form by the casting method. PVDF pellets were dissolved in dimethylacetamide (DMA), a HAP/DMA emulsion was prepared. The materials were mixed in proportions of 100/00, 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70 in weight and left to dry in an oven, resulting in homogeneous, flexible films which were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X ray diffractometry (XRD), contact angle measurement, and by mechanical and cytotoxicity tests.

Neste trabalho descreve-se a tecnologia envolvida na fabricação de um detector piroelétrico para aplicações na determinação da energia de feixe de lasers pulsados ou CW (onda contínua) modulados, utilizando-se do polímero Polifluoreto de Vinilideno PVDF. Os dados experimentais revelam que o detector tem resposta linear com a energia aplicada para o intervalo compreendido entre 0,4 a 6,8 mili-Joule/pulse para pulsos com largura temporal de 8,3 milissegundos.

This work describes the construction of a pyroeletric detector for measurements of laser pulse energy, using the polymer Polyvinylidene Fluorid (PVDF). The experimental data measured by detector showed a linear response for energy between 0,4 to 6,8 mJ/pulse for 8,3 milisecond duration pulse.