Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
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9 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.
- Influence of reprocessing on the mechanical properties of polyamide 6 containing talc(2016) DOMINGO, G. D.; Adriana Souza© 2016 Author(s).In this study, polyamide 6 containing 30wt% talc was reprocessed via injection molding up to eight processing cycles. The effects of reprocessing on the mechanical properties and on the melt viscosity were analyzed by flexural and impact tests and by melt flow index (MFI) tests, respectively. Flexural strength and modulus remained unchanged up to the 5th processing cycle. From the 6th processing cycle, flexural strength and modulus decrease with increasing processing cycles. Similar trend was observed for impact strength, however, the decrease observed in this property was much lower. From the 6th processing cycle, MFI increases with increasing processing cycles, indicating a possible reduction in PA6 molar mass.
- Mechanical properties of polyamide 12 after exposed to biodiesel(2016-10-31) NASCIMENTO, R. A.; Adriana Souza© 2016 Author(s).In this study, the mechanical properties of polyamide 12 (PA12) exposed to two types of fuel, B5 - market standard diesel with 5% biodiesel and B100 - pure biodiesel were investigated. The PA12 analyzed was a commercial grade VESTAMID®X7393, used for fuel hoses manufacturing. Samples for tensile and impact tests, obtained by injection molding, were immersed in two types of fuel (B5 and B100) contained in opaque vessels. Some vessels were stored at 100°C in an oven and the others were stored at room temperature. After remained immersed for a set time (1000, 3000 and 5000hours), the samples were taken out of the vessels and characterized by mechanical properties (tensile and impact strength). PA12 samples aged in B5 and B100 at 100°C presented a decrease in elongation at break and impact strength and an increase in Young modulus with increasing aging time. The tensile strength of PA12 aged in B5 and B100 decreased and increase, respectively, with increasing aging time. B5 was more aggressive than B100 for PA12. PA12 samples aged in B5 and B100 at room temperature presented a decrease in tensile strength with increasing aging time. From 3000 hours of aging, a decrease in Young modulus and an increase in impact strength was observed. This behavior was more pronounced for samples aged in B100.
- 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.
- Influence of MMT and PP-g-MA incorporation on the morphology and mechanical properties of PP/SEBS blends(2018-07-11) TORRECILAS, H. V.; COSTA, L. C.; Souza A. M. C. Adriana Souza© 2018 Author(s).Blends of PP/SEBS containing montmorillonite clay (MMT) was studied. Maleic anhydride grafted polypropylene (PP-g-MA) was added aiming interaction improvement between blend components and MMT. The blends were obtained using a co-rotational twin-screw extruder. Samples for tensile and impact tests were obtained by injection molding and were characterized by tensile and impact tests. The blend morphologies were characterized by scanning electron microscopy (SEM) and by transmission electron microscopy (TEM). PP/SEBS blends containing MMT presented an increase in Young Modulus and impact strength and a decrease in elongation at break. This behavior was greater in the presence of PP-g-MA. The presence of the PP-g-MA had attracted the organoclay to the matrix due to the interaction between the platelets and the maleic anhydride group. In this nanocomposite, it was observed the presence of MMT within PP matrix and a slight decrease of the dispersed phase diameter.
- 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.
- Recycled polycarbonate as impact modifier in polypropylene(2019-01-22) MICHEL HAU, J.B.X.; MICHEL HAU, J.B.X.© 2019 Author(s).Polypropylene (PP) is one of the most widely used commodity thermoplastics, such as in the automotive sector, in part, for being lightweight, flexible and strong, with high flexural fatigue strength. However, it displays low impact strength, which is commonly improved by adding elastomer. Elastomer, however, reduces tensile strength and stiffness. To increase impact strength without reducing tensile strength and stiffness PP was blended with recycled polycarbonate (PC) at 10, 20 and 30 wt%. Since these polymers are incompatible two compatibilizer have been tested in the blends, namely, maleic anhydride grafted PP, PPgMA, and a Lotader copolymer ethylene -co-methyl acrylate co-glycidyl methacrylate, P(E-co-MA-co-GMA). Two methods of blending have been tested: (i) tumble mixing of all components with subsequent extrusion and injection molding; and (ii) extrusion of PC/compatibilizer master-batch, with subsequent injection molding of tumble-mixed master batch plus PP. Specimens have been subjected to impact and tensile testing as well as scanning electron microscopy analysis. In terms of mechanical properties the best performance was found with the 80/20 PP/PC blend containing 10 wt% Lotader, prepared according to the first method of blending.
- Cross-linked polyethylene (XLPE) as filler in high-density polyethylene: Effect of content and particle size(2019-01-22) FREITAS, R. S.; Bonse B.C.© 2019 Author(s).Cross-linked polyethylene (XLPE) scrap from electrical wire and cables was micronized and separated in average particle sizes of 100, 500 and 900 micrometer, after which sheets of XLPE concentrates in high-density polyethylene HDPE were produced, using a calendaring process. The sheets were ground and incorporated into HDPE by means of a twin-screw co-rotating extruder and subsequently injection molded into test specimens. A 2 by 2 factorial design with center point was used, where XLPE contents varied between 1 and 9 wt% and average particle size between 100 and 900 micrometers were assessed as to the effect of XLPE content and particle size on HDPE mechanical properties. Increase in XLPE content significantly increased only impact strength, and decreased tensile and flexural strength, and flexural modulus. The effect on tensile modulus and strain at break was not significant for the adopted 95% confidence interval. The increase in XLPE average particle size affected positively only impact strength of the material, and decreased strain at break and flexural modulus. The effect on tensile and flexural strength and on tensile modulus was not significant for the adopted 95% confidence interval. The interaction between the two variables decreased impact strength and increased tensile modulus, and was not significant for the other investigated properties.