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Martinez Urreaga J.,Technical University of Madrid | Martinez Urreaga J.,Characterization and Applications Research Group | Gonzalez-Sanchez C.,University of Oviedo | Martinez-Aguirre A.,University of Oviedo | And 5 more authors.
Journal of Cleaner Production | Year: 2015

The use of blends of recycled agricultural plastic and post-consumer high-density polyethylene from municipal solid wastes, as matrices for sustainable eco-composites, was investigated with the aim of boosting the use of recycled materials and reducing the waste plastic environmental impact. It was proposed that proper selection of blends of different waste plastics will allow the production of composites with optimized properties. The two plastics and their blends were characterized by using different spectroscopic techniques and thermal analysis, and measuring the flow curves. The eco-composites were obtained by compounding a selected blend of recycled agricultural plastic and post-consumer polyethylene with different proportions of coupling agent and waste cellulose fibers in a pilot-plant twin-screw extruder. The structure of the final materials and the role of the coupling agent were analyzed by using scanning electron microscopy. Finally, the novel eco-composites were compared to their counterparts without post-consumer polyethylene, revealing that the incorporation of polyethylene increases the strength and stiffness of the eco-composites, without compromising the impact strength. The incorporation of 40wt% of polyethylene caused increases in moduli as high as 175% for the polymer and 47% for composites with 30% of fibers. The tensile strength increased up to 21% for the same composites. The decreases in processability caused by the incorporation of polyethylene can be corrected by increasing the coupling agent content. The improved balance between stiffness, strength and toughness without compromising processability can increase the recyclability of the polymer and cellulose wastes used in this work. © 2015 Elsevier Ltd.

Gonzalez-Sanchez C.,University of Oviedo | Martinez-Aguirre A.,University of Oviedo | Perez-Garcia B.,University of Oviedo | Acosta J.,Complutense University of Madrid | And 7 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2016

The enhancement of mechanical performance of waste-sourced biocomposites through peroxide induced crosslinking was investigated in order to expand their range of applications. Biocomposites containing 25 to 35 wt% of residual Kraft-pulp cellulose fibers, 1.5 wt% of a selected maleic-anhydride-modified polyethylene coupling agent and a 60/40 (w/w) of recycled agricultural plastic/post-consumer plastic blend were compounded in an extrusion-compounding pilot-plant. Changes in the blend structure due to the presence of the organic peroxide used were studied by spectroscopy and thermal analysis. It was found that the addition of extremely low amounts of peroxide (0.025-0.050 wt%) results in remarkable improvements in stiffness, strength and toughness of biocomposites, without compromising processability. Thus, their tensile strength and energy at break increased up to 89.4% and 138%, respectively, with regard to uncrosslinked biocomposites. Scanning electron microscopy revealed an improvement of the fiber-matrix adhesion due to the treatment with the peroxide. © 2015 Elsevier Ltd. All rights reserved.

De La Orden M.U.,Complutense University of Madrid | De La Orden M.U.,Characterization and Applications Research Group | Montes J.M.,Technical University of Madrid | Martinez Urreaga J.,Characterization and Applications Research Group | And 5 more authors.
Polymer Degradation and Stability | Year: 2015

Incorporation of a small content of undecenoic acid is proposed as an approach to introduce polar groups within the macromolecular architecture of high density polyethylene-based materials in order to promote an easier degradation after their useful service life. The influence of these hydrophilic groups during thermo and photo-oxidation processes has been then evaluated by several complementary techniques. In addition to different degradation rates, distinct ratios of oxidized species (lactones, ketones, carboxylic acids, esters and aldehydes) are found depending on: a) the initial material (neat high density polyethylene or ethylene-co-undecenoic acid copolymer); b) the type of oxidation (thermo or photoinduced); and c) the absence or presence of a specific prodegradant additive. An important increase of crystallinity has been observed in the final oxidized samples, indicating that the extent of degradation is rather significant. © 2014 Elsevier Ltd. All rights reserved.

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