Simple green approach to reinforce natural rubber with bacterial cellulose nanofibers

Natural rubber (NR) is a renewable polymer with a wide range of applications, which is constantly tailored, further increasing its utilizations. The tensile strength is one of its most important properties susceptible of being enhanced by the simple incorporation of nanofibers. The preparation and characterization of natural-rubber based nanocomposites reinforced with bacterial cellulose (BC) and bacterial cellulose coated with polystyrene (BCPS), yielded high performance materials. The nanocomposites were prepared by a simple and green process, and characterized by tensile tests, dynamical mechanical analysis (DMA), scanning electron microscopy (SEM), and swelling experiments. The effect of the nanofiber content on morphology, static, and dynamic mechanical properties was also investigated. The results showed an increase in the mechanical properties, such as Young's modulus and tensile strength, even with modest nanofiber loadings. © 2013 American Chemical Society.

Hybridization effect on the mechanical properties of curaua/glass fiber composites

The aim of this paper was to evaluate the effect of hybridizing glass and curaua fibers on the mechanical properties of their composites. These composites were produced by hot compression molding, with distinct overall fiber volume fraction, being either pure curaua fiber, pure glass fiber or hybrid. The mechanical characterization was performed by tensile, flexural, short beam, Iosipescu and also nondestructive testing. From the obtained results, it was observed that the tensile strength and modulus increased with glass fiber incorporation and for higher overall fiber volume fraction (%Vf). The short beam strength increased up to %Vf of 30 vol.%, evidencing a maximum in terms of overall fiber/matrix interface and composite quality. Hybridization has been successfully applied to vegetable/synthetic fiber reinforced polyester composites in a way that the various properties responded satisfactorily to the incorporation of a third component. © 2013 Published by Elsevier Ltd. All rights reserved.

Prospects for the use of municipal tree pruning wastes in particleboard production

The purpose of this study was to evaluate the physical and mechanical properties of particleboard made with pruning wastes from Ipê (Tabebuia serratifolia) and Chapéu-de-Sol (Terminalia catappa) trees. Particleboards were prepared with both wood species, using all the material produced by grinding the pruning wastes. The particleboards had dimensions of 45×45 cm, a thickness of approximately 11.5 mm and an average density of 664 kg/m3. A urea-formaldehyde adhesive was used in the proportion of 12% of the dry particle mass. The particleboards were pressed at a temperature of 130 C for 10 mins. The physical and mechanical properties analyzed were density, moisture content, thickness swelling, percentage of lignin and cellulose, modulus of resilience, modulus of elasticity and tensile strength parallel to the grain, accordingly to the standards NBR 14810 and CS 236-66 (1968). The particleboards were considered to be of medium density. The particle size significantly affected the static bending strength and tensile strength parallel to the grain. Ipê presented better results, demonstrating a potential for the production and use of particleboard made from this species. © The Author(s) 2013.

Resistência tênsil relacionada com atributos de um Latossolo sob sistema de semeadura direta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inter-relação do comprimento dos prolongamentos resinosos (tags) e da espessura da camada híbrida de adesão, com a resistência de união de sistemas adesivos ao tecido dentinário

Pós-graduação em Odontologia - FOA

Resistência de união de um sistema adesivo irradiado com laser Nd:YAG em dentina tratada com laser de Er:YAG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação da resistência á flexão e determinação das propriedades mecânicas de resinas compostas e sua aplicação no método dos elementos finitos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência de união em dentina de um adesivo de frasco único quando utilizado diferentes fontes de ativação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação in vitro da resistência de união do cerômero ao sistema de cimentação adesiva, através do teste de micro-tração. Efeito de diferentes tratamentos de superfície

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

Avaliação da resistência adesiva à microtração após desproteinização da dentina. Efeito de diferentes sistemas adesivos

Pós-graduação em Ciências Odontológicas - FOAR

Preparação e caracterização de filmes a base de xiloglucana extraída de sementes de Hymenaea Courbaril (Jatobá)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cationização de amidos de tuberosas tropicais para fabricação de papéis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de tubos de concreto reforçados com fibras de aço segundo a NBR 8890

Pós-graduação em Engenharia Civil - FEIS

Comportamento estrutural de lajes pré-moldadas treliçadas com adição de resíduos de borracha de pneu

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação do desempenho de argamassas com adição de cinza do bagaço de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)