Almudena Ochoa | Universidad Politécnica de Madrid (original) (raw)
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Papers by Almudena Ochoa
In the present work, polypropylene/cellulose fibres composite materials with maleated polypropyle... more In the present work, polypropylene/cellulose fibres composite materials with maleated polypropylene have carried out recycling cycles by injection in order to evaluate their recyclability regarding their industrial scale use. Moreover, the influence of the refining process in the fibers have been studied. The extensional resistance and Young Modulus properties loss in the third recycling cycle have been observed, although, the melt index increase with the increase of the number of recycling cycles.
Journal of Cleaner Production
La industria del envase metálico Más de 200 fábricas Más de 50.000 empleados Consumo: 4,5 Mt de m... more La industria del envase metálico Más de 200 fábricas Más de 50.000 empleados Consumo: 4,5 Mt de materia prima Más de 20.000 clientes Produce alrededor del 17% del conjunto de envases En Europa En España Facturación anual 2.000M€ aprox Consumo: 600.000t de materia prima 5.000 Empleados 21% de la producción se exporta Consumo y reciclado (t) de envases metálicos rígidos de uso doméstico en Europa-27,
Polymer Bulletin, 2020
The oxidation and thermal stability of low-density polyethylene (LDPE) films (stabilized and unst... more The oxidation and thermal stability of low-density polyethylene (LDPE) films (stabilized and unstabilized) used as greenhouse covering have been investigated. A mixture of kaolin, UV absorber, hindered amine light stabilizers (HALS) and heavy metals was used to stabilize LDPE films; these films were also compared with unstabilized LDPE films. Both films were exposed to natural weathering in Laghouat, Algeria. The oxidation resistance of unstabilized specimens for different ageing periods was determined by measuring the oxidation induction time (OIT) at 180 °C. It has been found that the highest OIT value was obtained for the unaged film and the values decline with ageing time. On the other hand, the stabilized specimens showed a significant stability under the conditions of OIT determination experiments. Furthermore, the oxidation resistance of these samples was evaluated by measuring the oxidation onset temperature (OOT). The results obtained showed that the OOT of the stabilized films ranges from 219 to 236 °C. Finally, a comparative analysis of the thermal stability results of both films was conducted. The activation energy of the photodegradation process of the both films was calculated by using TGA thermograms following the isoconversional approach. The results revealed that the stability of the stabilized specimens diminishes with ageing time and that the stabilizer additives improve the thermal stability of LDPE films. The influence of the photooxidation on the degree of crystallinity (based on DSC and WAXS techniques) of both films was also reported. Generally, there is a strong correlation between TGA, OIT, OOT, UV and FTIR results.
Materials Science and Engineering: C, 2015
Poly(lactic acid) (PLA) composites with titanium oxide (TiO 2)~10-nm nanoparticles were produced ... more Poly(lactic acid) (PLA) composites with titanium oxide (TiO 2)~10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased~12% when 5 wt.% of TiO 2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased~54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO 2 nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO 2 composites with 8 wt.% TiO 2 showed a reduction of Escherichia coli colonies of 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO 2 killing 94% of the bacteria. The PLA/TiO 2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation.
International Journal of Hydrogen Energy, 2015
Composites Part A: Applied Science and Manufacturing, 2015
ABSTRACT
Composites Part A: Applied Science and Manufacturing, 2011
ABSTRACT
In the present work, polypropylene/cellulose fibres composite materials with maleated polypropyle... more In the present work, polypropylene/cellulose fibres composite materials with maleated polypropylene have carried out recycling cycles by injection in order to evaluate their recyclability regarding their industrial scale use. Moreover, the influence of the refining process in the fibers have been studied. The extensional resistance and Young Modulus properties loss in the third recycling cycle have been observed, although, the melt index increase with the increase of the number of recycling cycles.
Journal of Cleaner Production
La industria del envase metálico Más de 200 fábricas Más de 50.000 empleados Consumo: 4,5 Mt de m... more La industria del envase metálico Más de 200 fábricas Más de 50.000 empleados Consumo: 4,5 Mt de materia prima Más de 20.000 clientes Produce alrededor del 17% del conjunto de envases En Europa En España Facturación anual 2.000M€ aprox Consumo: 600.000t de materia prima 5.000 Empleados 21% de la producción se exporta Consumo y reciclado (t) de envases metálicos rígidos de uso doméstico en Europa-27,
Polymer Bulletin, 2020
The oxidation and thermal stability of low-density polyethylene (LDPE) films (stabilized and unst... more The oxidation and thermal stability of low-density polyethylene (LDPE) films (stabilized and unstabilized) used as greenhouse covering have been investigated. A mixture of kaolin, UV absorber, hindered amine light stabilizers (HALS) and heavy metals was used to stabilize LDPE films; these films were also compared with unstabilized LDPE films. Both films were exposed to natural weathering in Laghouat, Algeria. The oxidation resistance of unstabilized specimens for different ageing periods was determined by measuring the oxidation induction time (OIT) at 180 °C. It has been found that the highest OIT value was obtained for the unaged film and the values decline with ageing time. On the other hand, the stabilized specimens showed a significant stability under the conditions of OIT determination experiments. Furthermore, the oxidation resistance of these samples was evaluated by measuring the oxidation onset temperature (OOT). The results obtained showed that the OOT of the stabilized films ranges from 219 to 236 °C. Finally, a comparative analysis of the thermal stability results of both films was conducted. The activation energy of the photodegradation process of the both films was calculated by using TGA thermograms following the isoconversional approach. The results revealed that the stability of the stabilized specimens diminishes with ageing time and that the stabilizer additives improve the thermal stability of LDPE films. The influence of the photooxidation on the degree of crystallinity (based on DSC and WAXS techniques) of both films was also reported. Generally, there is a strong correlation between TGA, OIT, OOT, UV and FTIR results.
Materials Science and Engineering: C, 2015
Poly(lactic acid) (PLA) composites with titanium oxide (TiO 2)~10-nm nanoparticles were produced ... more Poly(lactic acid) (PLA) composites with titanium oxide (TiO 2)~10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased~12% when 5 wt.% of TiO 2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased~54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO 2 nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2 h of contact the PLA/TiO 2 composites with 8 wt.% TiO 2 showed a reduction of Escherichia coli colonies of 82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO 2 killing 94% of the bacteria. The PLA/TiO 2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation.
International Journal of Hydrogen Energy, 2015
Composites Part A: Applied Science and Manufacturing, 2015
ABSTRACT
Composites Part A: Applied Science and Manufacturing, 2011
ABSTRACT