Exploring the microstructure of natural fibre composites by confocal Raman imaging and image analysis

Published Date
Composites Part A: Applied Science and Manufacturing
March 2017, Vol.94:32–40, doi:10.1016/j.compositesa.2016.12.005

• Author 

• Antoine Gallos ^a,b,,
• Gabriel Paës ^b
• David Legland ^c
• Florent Allais ^a,d
• Johnny Beaugrand ^b

• aChaire Agro-Biotechnologies Industrielles (Chaire ABI), AgroParisTech, 3 rue des Rouges Terres, F-51110 Pomacle, France
• bFractionnement des Agro Ressources et Environnement (FARE), INRA, University of Reims Champagne-Ardenne, 2 esplanade Roland Garros, F-51100 Reims, France
• cBiopolymères Interactions Assemblages (BIA), INRA, rue de la Géraudière, F-44316 Nantes, France
• dGénie et Microbiologie des Procédés Alimentaires (GMPA), INRA, AgroParisTech, CNRS, Université Paris-Saclay, avenue Lucien Brétignières, F78850 Thiverval-Grignon, France

Received 3 November 2016. Revised 30 November 2016. Accepted 3 December 2016. Available online 5 December 2016. 

Abstract

We describe a combination of Confocal Raman Imaging (CRI) and quantitative image analysis to characterise biocomposite material microstructures. Both techniques offer lateral resolutions close to 1.3 μm and axial resolution of 13 μm, while simplifying sample preparation to hand-cutting without any surface preparation. Extruded and injected polycaprolactone/hemp fibre composites were used as demonstration biocomposites. A green macrobisphenol additive (bis-O-dihydroferuloyl-1,4-butanediol) was also used as a chemical probe to characterise the dispersion efficiency of additives, with a detection threshold of 2.3 wt% above which very local heterogeneity can be determined by this technique. CRI provided microstructure information for the entire binary structure formed by the fibre network. The fibre dispersion and orientation depend on their location in the matrix, and the specific surface of the fibres increases with the fibre content as aggregates start to develop. The technique also highlighted a possible core-skin effect in the injected composite.

Abbreviations

BDF, bis-O-dihydroferuloyl-1,4-butanediol

CRI, Confocal Raman Imaging

PCL, polycaprolactone

NFC, Natural Fibre Composite

Keywords

D. Surface analysis

A. Natural fibre

B. Microstructure

C. Numerical analysis

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  Corresponding author at: Chaire Agro-Biotechnologies Industrielles (Chaire ABI), AgroParisTech, 3 rue des Rouges Terres, F-51110 Pomacle, France.

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