Canbio

Pau, France
Pau, France

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Sliwa F.,Canbio | Sliwa F.,French National Center for Scientific Research | El Bounia N.-E.,Canbio | Marin G.,French National Center for Scientific Research | And 2 more authors.
Polymer Degradation and Stability | Year: 2012

We have studied the thermal stability of a new family of wood polymer composites (WPC) which use a thermoplastic elastomer matrix (pebax® copolymers). These copolymers are poly(ether-b-amide) thermoplastic elastomers which show a significant elongation at break and a melting point below 200°C which helps prevent degradation of wood fibres upon processing. Moreover these polymers present a hydrophilic character able to interact with wood fibres. Another important feature is that these polymers are synthesized from renewable sources. We have been using two types of pebax® matrices and two species of wood flour as fillers. Composites were made by using a laboratory-size twin-screw extruder to obtain homogeneous composite pellets prior to injection moulding into tensile test samples. The thermal stability of the matrix, wood fibres and composites was investigated using thermogravimetric analysis under air and nitrogen atmosphere. In our study, we have shown a spectacular improvement of thermal stability of the composites under air atmosphere, as opposed to measurement performed under nitrogen. The presence of wood in pebax® hinders the thermo-oxidation in air by the formation of char residue in the earlier stage of degradation. We have also determined an optimal range of wood content in which we observe the protective synergism. © 2012 Elsevier Ltd. All rights reserved.


Sliwa F.,Canbio | Sliwa F.,University of Pau and Pays de l'Adour | El Bounia N.-E.,Canbio | Charrier F.,University of Pau and Pays de l'Adour | And 2 more authors.
Composites Science and Technology | Year: 2012

The aim of this investigation was to study a new family of wood polymer composites with thermoplastic elastomer matrix (pebax® copolymers) instead of commonly used WPC matrices. These copolymers are polyether-b-amide thermoplastic elastomers which present an important elongation at break and a melting point below 200. °C to prevent wood fibers degradation during processing. Moreover these polymers are synthesized from renewable resources and they present a hydrophilic character which allow them to interact with wood fibers. We have used two pebax® grade with different hardness and three types of wood fibers, so the influence of the matrix and wood fibers characteristics were evaluated. Composites were produced using a laboratory-size twin screw extruder to obtain composite pellets prior to injection moulding into tensile test samples. We have evaluated fibers/matrix interaction by differential scanning calorimetry (DSC), infrared spectroscopy (IRTF) and scanning electron microscopy (SEM). Then, the mechanical properties, through tensile test, were assessed. We also observed fibers dispersion into the matrix by tomography X. DSC, IRTF and SEM measurements confirmed the presence of strong interface interactions between polymer and wood. These interactions lead to good mechanical properties of the composites with a reinforcement effect of wood fibers due also to a good dispersion of fibers into the matrix without agglomerate. © 2012 Elsevier Ltd.

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