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33 results on '"Calvo-Correas, Tamara"'

27. Biobased polyurethanes and nanocomposites. From structure/properties relationship to shape-memory behavior

Author

Calvo Correas, Tamara, Corcuera Maeso, María Ángeles, and Eceiza Mendiguren, María Aranzazu

Subjects
composite polymers, polyurethanes, macromoléculas, macromolecules, poliuretanos, polímeros compuestos
Abstract

325 p., This work deals with the increase of the renewability of different porous and solid (thermoplastic and crosslinked) polyurethanes and bionanocomposites, by the incorporation of different reactants and nanoentities from renewable sources. Moreover, the influence of the nature of the reactants and nanoentities and their content on the final properties has been deeply studied.Besides, the synthesized solid polyurethanes and bionanocomposites have shown shape-memory properties. Therefore, the effect of the programming conditions, content of the reactants and, in the case of the bionanocomposites, nanoentity nature and content on shape-memory properties has been thoroughly analyzed., GMT.Materials + Technologies Research Group

Published
2017

28. Comparative effects of two different crosslinkers on the properties of vegetable oil‐based polyurethanes.

Author

Meiorin, Cintia, Calvo‐Correas, Tamara, Mosiewicki, Mirna Alejandra, Aranguren, Mirta Inés, Corcuera, Maria Angeles, and Eceiza, Arantxa

Subjects
POLYOLS, CASTOR oil, POLYURETHANES, FOURIER transform infrared spectroscopy, CONTACT angle, SCANNING electron microscopy, PHASE separation
Abstract

Thermoset polyurethanes (PUs) were prepared from a polyol derived from castor oil, 4,4′‐methylene diphenyl diisocyanate (MDI) and different trifunctional low‐molecular‐weight crosslinkers, biobased glycerol (Gly) and petroleum‐derived trimethylolpropane (TMP). The synthesis was carried out in bulk and without catalyst via one‐step polymerization varying the components equivalent weight ratio, Polyol:MDI:Gly and Polyol:MDI:TMP, respectively. The physicochemical, morphological, thermal, dynamic–mechanical, and mechanical properties of the PUs were determined. The success of the reaction between the polyol and MDI was confirmed by Fourier transform infrared spectroscopy. The dynamic–mechanical and the mechanical properties as well as hardness were determined and related to the concentration of the low‐molecular‐weight crosslinkers utilized (Gly or TMP). However, important differences were observed between the synthesized two series, due to phase separation produced during the curing reaction, which affected more the materials prepared from TMP. Scanning electron microscopy images and dynamic–mechanical results confirmed this difference, related to the reactivity of primary and secondary hydroxyls present in the crosslinkers. Thermogravimetric analysis also showed to be sensible to the different structure of the crosslinkers with TMP leading to more thermally stable samples. Finally, measurements of water contact angle indicated that the surfaces were mostly hydrophobic with minor differences between the samples. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48741. [ABSTRACT FROM AUTHOR]

Published
2020
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33. Biocompatible thermoresponsive polyurethane bionanocomposites with chitin nanocrystals.

Author

Calvo‐Correas, Tamara, Garrido, Patricia, Alonso‐Varona, Ana, Palomares, Teodoro, Corcuera, M. Angeles, and Eceiza, Arantxa

Subjects
THERMORESPONSIVE polymers, BIOMEDICAL materials, POLYURETHANES, NANOCRYSTALS, CRYSTALLINITY, CELL-mediated cytotoxicity
Abstract

In this work, different thermoresponsive biobased polyurethane (PU) bionanocomposites with chitin nanocrystals (CHNCs) are prepared. The behavior of the biobased PU used as matrix differs from common polyurethanes, since hard segment is constituted by the macrodiol and soft segment by a biobased diisocyanate and chain extender. The effect of CHNC content on shape‐memory behavior is studied. It is observed that CHNCs tend to interact with diisocyanate/chain extender rich domain. In addition, an increase of the overall crystallinity of the material is also observed. Therefore, the addition of CHNCs contributes to the shape recovery of the bionanocomposites, as well as to shape fixity at high CHNC content. Finally, the cytotoxicity, hemocompatibility, and cell adhesion analysis reveals that the prepared bionanocomposites show potential to be used in biomedical applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47430. Thermo‐activated shape‐memory response of a polyurethane bionanocomposite with a 3 wt% of chitin nanocrystals. [ABSTRACT FROM AUTHOR]

Published
2019
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