Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
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4 resultados
Resultados da Pesquisa
- Properties of lignocellulosic composites of coffee husk filled polypropylene(2020-01-10) LEAL, H. D. A.; BABETTO, A. S.; BONSE, B. C.© 2020 Author(s).Ground coffee husk has been incorporated into polypropylene (PP) at 20, 30 and 40 wt%, along with a PP maleated compatibilizer at 10 wt% relative to the coffee husk, by means of a co-rotating twin-screw extruder and subsequent injection molding into test specimens. In relation to neat PP, the 40 wt% composite showed an increase in flexural strength, flexural modulus, tensile modulus and heat distortion temperature of about 35, 90, 75 and 45%, respectively. However, strain at break, impact and tensile strength decreased by around 95, 40 and 20%, respectively. The presence of coffee husk practically did not affect PP melt temperature, but increased both composite's degree of crystallinity, measured by DSC, and temperature at maximum degradation rate, measured by TGA.
- Effect of calcium carbonate particle size and content on polyamide 6 processing and properties(2016-10-31) BONSE, B. C.; MOLINA, L. M.© 2016 Author(s).Three different types of calcium carbonates, including a nanosize one, were incorporated into polyamide 6, at different contents (5, 10 and 20 wt%) using a corotating twin-screw extruder connected to a Haake torque rheometer. Spherical-like nanosize CaCO3 particles and needle-like precipitated CaCO3 showed to consist of calcite crystals, whereas needle-like naturally occurring CaCO3 particles consisted of both calcite and aragonite. Specimens were injection molded and subjected to tensile, bending and impact testing. XRD, SEM and DSC analyses were also carried out. Both conventional and nanocalcium carbonate reduced torque, with the nano resulting in lower values. All investigated calcium carbonates increased PA6 tensile and flexural strength and elastic modulus.
- Sawdust reinforced polypropylene: Effect of plasticizer incorporation method and properties(2018-07-11) MAZARIM, G. C.; BONSE, B. C.© 2018 Author(s).Polypropylene reinforced sawdust composites containing paraffinic and vegetable plasticizer, at 5 and 10 wt%, were prepared according to two methods. In the first method, PP, sawdust, compatibilizer and plasticizer were pre-mixed, extruded in a co-rotating twin-screw extruder and injection molded. In the second, plasticizer was added to the extruded composite pellets and then injection molded. The addition of plasticizer reduced tensile and flexural strength, as well as elastic modulus of the composite, and increased impact strength, tensile strain at break and toughness. As to plasticizer type, both had similar effects on impact strength, tensile strain at break and flexural modulus. With the paraffin oil, the increase in toughness of the PP sawdust composite was higher and the decrease in tensile and flexural strength was lower compared to the vegetable oil. Except for impact strength and flexural modulus the method of plasticizer incorporation, statistically, showed no difference in the investigated composite properties; however, deviation around the mean was higher when the plasticizer was added prior to injection molding, compared to addition in the pre-mixing stage.
- Saw dust reinforced toughened polypropylene (PP/EPDM/talc): Effect of plasticizer incorporation(2019-01-22) PINTO, G. M.; BONSE, B. C.© 2019 Author(s).The effect of a paraffinic and a vegetable plasticizer on the mechanical and thermal properties of sawdust reinforced toughened polypropylene (PP/EPDM/talc) was studied, employing two different methods of plasticizer incorporation. The first method is based on pre-mixing all components in a tumble mixer, extrusion in a co-rotational twin-screw extruder and injection molding. In the second method the plasticizer was added in the injection molding hopper, after extrusion of the other components. The addition of 10wt% paraffinic plasticizer increased impact strength of the plasticizer-free composite by almost 50% for both incorporation methods, while the increase generated by the addition of 10wt% vegetable plasticizer was only 30%. The compounds containing 10wt% paraffinic plasticizer presented tensile and flexural strength, slightly higher than that presented by the compounds containing 10wt% vegetable plasticizer. A significant conclusion of this study is when comparing the responses regarding the plasticizer incorporation methods. There was practically no difference in the investigated properties, either mechanical or thermal, when the plasticizer was added in the extrusion or injection stage, which means one step less in the processing of the composite.