Natural fibre thermoplastic tapes to enhance reinforcing effects in composite structures

Semi-consolidated thermoplastic tapes were produced by spreading flax and polypropylene matrix fibres using a newly developed technology. This lightweight tape was structurally stable and contained 38% flax fibres by volume. The tapes were processed in unidirectional and woven fabric format for composite fabrication. Hot pressed moulded thermoplastic laminates were fabricated and their properties were compared to those of flax/PP yarn based thermoplastic composites with equivalent fibre content. We found that the flax/PP tape-based composites had less void content, 60-110% higher flexural modulus and 35-65% higher tensile modulus compared to flax/PP yarn based thermoplastics. Thermoanalytical results showed that the heating conditions used in the tape-making process did not degrade the flax fibres and PP matrix. We conclude that such semi-consolidated flax/PP tapes enable the achievement of properties not seen before for yarn-based composites, and therefore are an important step forward in optimising the reinforcing effect of natural fibres in composite applications

Natural fibre thermoplastic tapes to enhance reinforcing effects in composite structures

Semi-consolidated thermoplastic tapes were produced by spreading flax and polypropylene matrix fibres using a newly developed technology. This lightweight tape was structurally stable and contained 38% flax fibres by volume. The tapes were processed in unidirectional and woven fabric format for composite fabrication. Hot pressed moulded thermoplastic laminates were fabricated and their properties were compared to those of flax/PP yarn based thermoplastic composites with equivalent fibre content. We found that the flax/PP tape-based composites had less void content, 60-110% higher flexural modulus and 35-65% higher tensile modulus compared to flax/PP yarn based thermoplastics. Thermoanalytical results showed that the heating conditions used in the tape-making process did not degrade the flax fibres and PP matrix. We conclude that such semi-consolidated flax/PP tapes enable the achievement of properties not seen before for yarn-based composites, and therefore are an important step forward in optimising the reinforcing effect of natural fibres in composite applications

A novel non-crimped thermoplastic fabric prepreg from waste carbon and polyester fibres

A biaxial non-crimped fabric, 400 ± 10 g/m2, +45°/−45° lay-up protocol, was made from a unidirectional tape comprised of a 60/40 wt% carded blend of virgin waste carbon fibres, 60 mm chopped length, and polyester resin fibres, 60 mm staple length. The non-crimped fabric was used as a thermoplastic prepreg to produce laminated composite panels. The prepreg exhibited a high degree of drapeability. The physical and mechanical properties of composite samples were determined; the density, void contents, tensile and flexural strengths and moduli were found to be 1.5 g/cm3, 10%, 180.7 MPa, 260.5 MPa, 34.2 GPa and 30.4 GPa, respectively. Modification of the consolidation process and the use of finer polyester fibres should decrease the void content. It was concluded that waste carbon fibres can be converted into flexible/drapeable dry prepreg materials, potentially useful for the manufacturing of thermoplastic composite products by hot press compaction. </jats:p

Mechanical properties of recycled carbon fibre/polyester thermoplastic tape composites

The increasing use of high-value carbon fibre in composites is linked with increasing waste generation: from dry fibre and prepreg offcuts during manufacturing to end-of-life parts. In this work, a novel thermoplastic tape was produced from 60 wt.% manufacturing waste carbon fibres (60 mm long) and 40 wt.% polyester fibres using a thermal consolidation technique. The thin (0.2 mm) and narrow (20 mm wide) tapes were then used to fabricate laminated composite panels in two 0/90 tape architectures: cross-ply and woven ply. Various mechanical properties, including tensile, flexural, compression and impact were evaluated. It was found that cross-ply performed better than woven ply laminates, with failure in the latter materials typically initiating at the tape interlacement points. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors would like to thank Tilsatec Advanced Textile Materials and School of Materials, University of Manchester for supporting this study project.This is the author accepted manuscript. The final version is available from SAGE Publications via https://doi.org/10.1177/002199831667209