Development of a new hybrid yarn construction from recycled carbon fibres for high-performance composites: Part IV: Measurement of recycled carbon fibre length

Abstract

Due to the increasing application of carbon fibre–reinforced plastics, the use of recycled carbon fibres can help reduce the tremendous amount of carbon fibre waste growing worldwide. In this context, the processing of longer recycled carbon fibres (>40 mm mean length) into hybrid yarn constructions offers a promising solution. The characterisation of recycled carbon fibre length is essential for textile processes. However, to suit the atypical fibre characteristics of recycled carbon fibres compared to standard natural or man-made-fibres, the development of an adequate measuring technique is required. Investigations on the state of the art suggest that an adapted fibrograph method might pose an appropriate measuring system. Therefore, new test equipment and an alternative image analysing method based on pixel greyscale values were developed. To enable a calibration process, different samples with cut carbon fibre from carded and drafted slivers were intensively tested and compared. In addition, an adapted reference method was investigated by combining single fibre measurement and image processing techniques. In a final step, recycled carbon fibres samples with unknown fibre length were tested. Results proved that the presented measuring system is adequate for the testing of longer recycled carbon fibres in webs or slivers. All measured values were close to the measured reference length values (deviation ±4%).

Theoretical modeling of tensile properties of thermoplastic composites developed from novel unidirectional recycled carbon fiber tape structure

“…Therefore, mean fiber length and SFC of recycled carbon fibers was measured from the developed unidirectional tape structure. For this purpose, tape structure without thermal fixation was developed and subjected to image analysis method 18,19 for the assessment of mean fiber length present in the structure.…”

“…The fiber beard in a range of 150 ± 20 milligrams was scanned and grayscale densities of different class lengths were employed to draw a staple length diagram as shown in the Figure 3(b).

Figure 3.Image analysis method (a) fibre beard (b) fibre length distribution. 18,19

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Recent developments in yarn formation technology for producing innovative hybrid yarn structures from staple carbon and thermoplastic fibers for high-performance composites

“…While the fiber orientation and length in hybrid sliver determine the mechanical response of hybrid yarns and composites. 37,49 In order to assess sliver structure, three hybrid slivers with material combinations, C 40 P 40 V 50 , C 60 P 60 V 50 and C 80 P 60 V 50 , were developed and subjected to the Lindsey 50 image analysis 51 and cut-and-weight methods 52 to determine the fiber orientation, fiber length and uniformity in the structure.…”

A two‐stage analysis for the role of fiber size in terms of length distribution on the performance under accelerated weathering tests of oil palm empty fruit bunch fiber‐reinforced vinyl acrylic composites

“…5 Despite the relevance of this subject, less research has been done on it due to extremely time-consuming demands from several methodologies to carry out this task, not to mention the physical constraints of specialized equipment to analyze fibers of this nature. 6 Thus, with the aim of keeping the methodology as simple as possible, a facile and replicable procedure was employed to overcome this issue based on previously developed work. 7 From which numerous length measurements of OPEFB fibers were obtained-far more than the number recommended for accurate characterization of fiber length distribution (at least 2000 measurements 8 )-along with a statistical analysis of the distribution followed by the fiber length data.…”

“…Hence, measuring the variability of fiber length should become a priority both in order to understand and to specify its influence over the resulting composite properties 5 . Despite the relevance of this subject, less research has been done on it due to extremely time‐consuming demands from several methodologies to carry out this task, not to mention the physical constraints of specialized equipment to analyze fibers of this nature 6 . Thus, with the aim of keeping the methodology as simple as possible, a facile and replicable procedure was employed to overcome this issue based on previously developed work 7 .…”