Number of processing cycle effect on the properties of the composites based on alfa fiber

Abstract

The objective of the investigation described in this work was to study the reprocessing effects on the alfa fiber reinforced polyvinylchloride composites with and without maleic anhydride-grafted polyvinyl chloride used as compatibilizer. The material was characterized after each extrusion using tensile tests, scanning electron microscopy (SEM), dynamic mechanical, and thermal analysis. Results indicated that generally after four cycles, the recycled composites had considerably higher modulus as compared with the original composites, which were attributed to changes in physical and chemical properties of the composites induced by the recycling process. This effect was enhanced for the compatibilized samples. Increase of the modulus strength of the poly(vinyl chloride) (PVC) matrix is detected due to the molecular chain cross-linking resulting from degradation. In addition, it was found that the reprocessing cycles increase in glass transition temperature of PVC and PVC/alfa composites.

Influence of reprocessing on fibre length distribution, tensile strength and impact strength of injection moulded cellulose fibre-reinforced polylactide (PLA) composites

“…A decrease in fibre length during reprocessing was found for all cited studies. An opposite trend was observed for the void fraction, which was observed to decrease during reprocessing, leading to a more homogeneous composite structure and a better wetting of the fibres within the matrix [12,13]. The main problem which appears during reprocessing is the shortening of fibres, leading to a lower aspect ratio when single man-made fibres are considered.…”

“…This phenomenon was observed by different authors for different natural fibre bundles in variable matrices, eg. for flax/PLA [9], flax/PP [4,8], hemp/PP [2,3], sisal/PP [2,3], wood fibre/PP [4] or alfa fibre/PVC [12]. Nevertheless, the fibre bundle may be damaged with an increasing number of recycling steps, especially if the fibre bundles are already split into single fibres, leading to lower mechanical composite characteristics as a consequence of reprocessing [2,3].…”

“…Some approaches exist for the mechanical reprocessing of composites and the further processing by injection moulding, e.g. for flax fibre-reinforced PP [4,8], flax fibre-reinforced polylactide (PLA) [9], hemp fibre-reinforced PP [2,3], sisal fibre-reinforced PP [2,3], wood fibre-reinforced PP [4,10], wood fibrereinforced high density polyethylene (HD-PE) [11] or alfa fibre-reinforced polyvinylchloride (PVC) [12]. A decrease in fibre length during reprocessing was found for all cited studies.…”

Effect of Recycling Cycles on the Mechanical and Damping Properties of Short Alfa Fibre Reinforced Polypropylene Composite

“…As to PP based eco-composites, it is generally expected to have less recyclability than the pure PP because of the heterogeneous and the inherent lower thermal stability of natural fibres. Despite these difficulties, several research works have been interested in recycling natural fibres reinforced polymer composites [5][6][7][8][9]. For example, Bourmaud and Baley [5] studied the mechanical and thermo-physical behaviour of recycled short hemp and sisal fibres reinforced PP.…”

“…About alfa fibre reinforced polymer, few researchers studied the effect of recycling on their mechanical properties. To the author's knowledge, only one study was conducted by Hammiche et al [8]. They showed that the tensile strength and Young's modulus of short alfa fibre reinforced polyvinylchloride were enhanced after four recycling cycles.…”