Alternatives Panels from Waste Plastics Reinforced With Fibers of Pupunha Palm for Use in Civil Construction and Furniture Industry

In order to cooperate in minimizing the problems of the current and growing volume of waste, this work aims at the production of panels made from industrial waste -thermoplastic (Polypropylene - PP; Polyethylene - PE and Acrylonitrile Butadiene Styrene - ABS) reinforced with agro-industrial waste - pupunha palm waste (shells and sheaths). The properties of the panels were evaluated: density, thickness swelling, water absorption and moisture content. It was used the ASTM D1037; EN 317; and ANSI A208.1 standards regarding particle boards. The best results in physical tests were treatments 1 (100% waste plastic), 6 (60% plastic waste and 40% waste of pupunha) and 7 (70% waste plastic and 30% waste of pupunha). The best results in the mechanical tests were treatments 3 (30% de residuos plasticos e 70% de residuos da pupunha), 4 (40% de residuos plasticos c 60% de residuos da pupunha) and 5 (50% de residuos plasticos e 50% de residuos da pupunha). For mechanical tests it was concluded that the results of modulus of rupture and of modulus of elasticity the best treatments were those with more fibers. In the tensile tests perpendicular to the surface, it is clear that using more waste plastics leads to the best results. It was concluded that the waste can be used as raw material for the production of alternative materials mainly in civil construction and furniture industries, and it can be employed in urban or rural environment, given the concept of eco-efficient products.

Electrical properties of a composite of Polyurethane and ferroelectric ceramics

Ferroelectric ceramic particles based on lead titanate zirconate (PZT) were dispersed in a polymer matrix based on castor oil. After the poling process, the pyroelectric activity of this composite was measured using a direct method in which a linear heating rate was applied to the pre-poled samples. The pyroelectric coefficient at 343 K is comparable with that of a PZT-poly(vinylidene fluoride) (PVDF) composite and significantly higher than that of PVDF. © 1998 Kluwer Academic Publishers.

Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics: The effect of surface conditioning

Purpose: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (In-Ceram Zirconia) ceramics. Materials and Methods: Ten blocks (5 ×6 × 8 mm) of In-Ceram Alumina (AL), In-Ceram Zirconia (ZR), and Procera (PR) ceramics were fabricated according to each manufacturer's instructions and duplicated in composite. The specimens were assigned to one of the two following treatment conditions: (1) airborne particle abrasion with 110-μm Al2O3 particles + silanization, (2) silica coating with 30 μm SiOx particles (CoJet, 3M ESPE) + silanization. Each ceramic block was duplicated in composite resin (W3D-Master, Wilcos, Petrópolis, RJ, Brazil) using a mold made out of silicon impression material. Composite resin layers were incrementally condensed into the mold to fill up the mold and each layer was light polymerized for 40 s. The composite blocks were bonded to the surface-conditioned ceramic blocks using a resin cement system (Panavia F, Kuraray, Okayama, Japan). One composite resin block was fabricated for each ceramic block. The ceramic-composite was stored at 37°C in distilled water for 7 days prior to bond tests. The blocks were cut under water cooling to produce bar specimens (n = 30) with a bonding area of approximately 0.6 mm2. The bond strength tests were performed in a universal testing machine (crosshead speed: 1 mm/min). Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (≤ 0.05). Results: Silica coating with silanization increased the bond strength significantly for all three high-strength ceramics (18.5 to 31.2 MPa) compared to that of airborne particle abrasion with 110-μm Al2O3 (12.7-17.3 MPa) (ANOVA, p < 0.05). PR exhibited the lowest bond strengths after both Al2O3 and silica coating (12.7 and 18.5 MPa, respectively). Conclusion: Conditioning the high-strength ceramic surfaces with silica coating and silanization provided higher bond strengths of the resin cement than with airborne particle abrasion with 110-μm Al2O3 and silanization.

Analysis of mechanical behavior in bending of polymer composites using the finite elements method

The use of composite materials has increased in the recent decades, mainly in the aeronautics and automotives industries. In the present study is elaborated a computational simulation program of the bending test using the finite elements method, in the commercial software ANSYS. This simulation has the objective of analyze the mechanical behavior in bending of two composites with polymeric matrix reinforced with carbon fibers. Also are realized bending tests of the 3 points to obtain the resistances of the materials. Data from simulation and tests are used to make a comparison between two failures criteria, Tsai-Wu and Hashin criterion. Copyright © 2009 SAE International.

Characterization of high density polyethylene (HDPE) reinforced with banana peel fibers

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

Evaluation of weather influence on mechanical and viscoelastic properties of polyetherimide/carbon fiber composites

In order to investigate how environmental degradation affects the mechanical and thermal performance of polyetherimide/carbon fiber laminates, in this work different weathering were conducted. Additionally, dynamic mechanical analysis, interlaminar shear strength tests and non-destructive inspections were performed on this composite before and after being submitted to hygrothermal, UV radiation and thermal shock weathering. According to our results, hygrothermally aged samples had their glass transition temperature and elastic and storage moduli reduced by plasticization effect. Photooxidation, due to UV radiation exposure, occurred only on the surface of the laminates. Thermal shock induced a reversible stress on the composite's interface region. The results revealed that the mechanical behavior can vary during weather exposure but since this variation is only subtle, this thermoplastic laminate can be considered for high-performance applications, such as aerospace. © The Author(s) 2013.

Efeito do condicionamento ambiental nas propriedades de cisalhamento e viscoelásticas de compósitos híbridos metal-fibra

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

In vitro analysis of shear bond strength and adhesive remnant index comparing light curing and self-curing composites

OBJETIVO: Avaliar in vitro a resistência ao cisalhamento de compósitos autopolimerizáveis (Concise e Alpha Plast) e fotopolimerizáveis (Transbond XT e Natural Ortho) utilizados na colagem de braquetes metálicos da marca Morelli, analisando o índice de adesivo remanescente (ARI) e da integridade da superfície do esmalte por meio de microscopia eletrônica de varredura (MEV). MÉTODOS: foram utilizados 40 pré-molares humanos extraídos. As raízes dos dentes foram incluídas em gesso-pedra especial, no interior de tubos de PVC usados para a confecção dos corpos de prova. Esses corpos de prova foram divididos em quatro grupos: grupo G1, braquetes associados ao compósito Concise; grupo G2, braquetes associados ao compósito Alpha Plast; grupo G3, braquetes associados ao compósito Transbond XT; e grupo G4, braquetes associados ao compósito Natural Ortho. Os grupos foram submetidos ao teste de cisalhamento em máquina universal de ensaios, a uma velocidade de 0,5mm por minuto. RESULTADOS: houve diferença estatística entre os grupos G3 e G4, sendo os valores de G4 superiores; no entanto, não foram encontradas diferenças estatisticamente significativas entre os grupos G1, G2 e G3 e G1, G2 e G4. Na análise do ARI não foram encontradas diferenças estatísticas entre os grupos, predominando escores baixos. De acordo com a análise da MEV, constatou-se o rompimento dos compósitos e a integridade do esmalte entre os grupos. CONCLUSÃO: a resistência ao cisalhamento foi satisfatória e semelhante entre os compósitos utilizados, sendo que a resina Natural Ortho apresentou-se superior à Transbond XT.

Environmental effects on viscoelastic behavior of carbon fiber/PEKK thermoplastic composites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nonoxidative thermal degradation kinetic of polyamide 6,6 reinforced with carbon nanotubes

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

Tricot stitched carbon fiber reinforced polymer composite laminates manufactured by resin transfer molding process: C-scan and flexural analysis

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

Effect of colloidal silica on the mechanical properties of fiber-cement reinforced with cellulosic fibers

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

Processing and characterization of ablative composites used in rocket motors

The main objective of this research work was to obtain two formulations of ablative composites. These composites are also known as ablative structural composites, for applications in atmospherically severe conditions according to the high-temperature, hot gaseous products flow generated from the burning of solid propellants. The formulations were manufactured with phenolic resin reinforced with chopped carbon fiber. The composites were obtained by the hot compression molding technique. Another purpose of this work was to conduct the physical and chemical characterization of the matrix, the reinforcements and the composites. After the characterization, a nozzle divergent of each formulation was manufactured and its performance was evaluated through the rocket motor static firing test. According to the results found in this work, it was possible to observe through the characterization of the raw materials that phenolic resins showed peculiarities in their properties that differentiate one from the other, but did not exhibit significant differences in performance as a composite material for use in ablation conditions. Both composites showed good performance for use in thermal protection, confirmed by firing static tests (rocket motor). Composites made with phenolic resin and chopped carbon fiber showed that it is a material with excellent resistance to ablation process. This composite can be used to produce nozzle parts with complex geometry or shapes and low manufacturing cost.

Medium density particleboard reinforced with bamboo laminas

The objective of this work was to evaluate the effect of the addition of bamboo laminas of the species Dendrocalamus giganteus to three-layer medium density particleboard (MDP). These laminas were glued onto both the top and the bottom of each panel. With the manufactured panels laminated with bamboo, mechanical tests based on the Brazilian Standard ABNT NBR 14810 were carried out to determine the modulus of rupture (MOR) in static bending and the tensile strength parallel-to-surface. These mechanical tests were realized in particleboards of eucalyptus and in reinforced particleboard, both produced in the laboratory. The modulus of rupture and tensile strength parallel-to-surface of the laminated MDP had values close to those that have been reported. The reinforcements increased the values of these studied properties. Nevertheless, this fact indicated the possibility to produce a stronger MDP using bamboo lamina as surface layers. These results show the possibility of using coatedbamboo MDP for utilization in large spans, for example, in flooring for mezzanines with finish on both sides, and for robust furniture as bookshelves, beds, tables, etc.