Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
Navegar
3 resultados
Resultados da Pesquisa
- Mechanical and thermal behavior of aged composites of recycled PP/EPDM/talc reinforced with bamboo fiber(2018) Inacio A.L.N.; Nonato R.C.; Bonse B.C.LtdNatural fiber reinforced thermoplastic composites have been widely studied, mostly for environmental and economic reasons. One promising application is in the automotive industry, which widely uses talc filled EPDM (ethylene-propylene-diene monomer) toughened polypropylene (PP) for manufacturing interior and exterior vehicle components. It is important to analyze the durability of these materials since automotive vehicles have a long life cycle. The aim of this study was to assess mechanical and thermal properties of aged composites containing bamboo fiber reinforced recycled talc-filled PP/EPDM compatibilized with maleic anhydride grafted polypropylene (PP-g-MAH). Composites were prepared according to a 2 by 2 factorial design with center point, in a Haake twin screw extruder and injection molded. Specimens were aged for seven days at 90 °C in a chamber with hot air circulation. Addition of bamboo fiber significantly increased tensile and flexural strength, modulus and fatigue life, and decreased elongation at break and impact strength. Addition of the compatibilizer had a positive effect only on tensile and flexural strength, and fatigue life whereas the effect was negative on elongation at break and impact strength. The addition of fiber and PP-g-MAH, at levels exceeding 2 wt%, increased the degradation temperature of the fiber.
- Investigation on the use of coir fiber as alternative reinforcement in polypropylene(2010) Bettini S.H.P.; Bicudo A.B.L.C.; Augusto I.S.; Antunes L.A.; Morassi P.L.; Condotta R.; Bonse B.C.Polypropylene/coir fiber composites were prepared according to an experimental statistical design, in which the independent variables, coir fiber, and compatibilizer content, were varied. The compatibilizer used was maleic anhydride grafted polypropylene (PP-g-MA). Compatibilizer free composites were also prepared. Composites were processed in a corotating twin-screw extruder and submitted to mechanical and morphological analyses. The effects of the independent variables on the mechanical properties were assessed through tensile strength, elongation at break, flexural modulus, and impact strength. The morphological properties were assessed by scanning electron microscopy (SEM). The results indicated the need for using compatibilizers in the composites due to the incompatibility of PP and coir fiber. The variable with the strongest effect on the properties was coir content, whose increase caused increase in tensile strength, impact strength and elastic modulus, and decrease in elongation at break. The presence of PP-g-MA was fundamental to achieving the aforementioned results. The effect of increasing compatibilizer content was only observed for the elastic modulus. © 2010 Wiley Periodicals, Inc.
- Effect of sawdust surface treatment and compatibilizer addition on mechanical behavior, morphology, and moisture uptake of polypropylene/sawdust composites(2010) Bettini S.H.P.; Bonse B.C.; Melo E.A.; Munoz P.A.R.Polypropylene/sawdust composites were investigated to assess the effect of sawdust surface treatment and compatibilizer addition on polymer/fiber adhesion. Two silane coupling agents were used for sawdust surface treatment: vinyl-tris (2-methoxyethoxy) silane and (3- aminopropyl)triethoxysilane. Maleic anhydride grafted polypropylene was used as compatibilizer. Composites were prepared in a corotating twin-screw extruder coupled to a Haake torque rheometer and submitted to tensile and bending tests as well as scanning electron microscopy (SEM). Moisture uptake tests were also performed. Results showed that incorporation of untreated sawdust to polypropylene (PP) caused reduction in composite tensile strength and increase in stiffness. When the only treatment used was surface modification with silane coupling agents, no significant changes were observed in mechanical properties. However, when compatibilizer was added to the composites, tensile strength was increased, and % elongation at break reduced, indicating improved system compatibility. The composite presenting the highest increase in tensile strength was that containing sawdust treated with amino silane in addition to the compatibilizer. SEM analyses corroborated the mechanical property results. © 2009 Society of Plastics Engineers.