TY - JOUR
T1 - Characterisation and improvement of the quality of mixing of recycled thermoplastic composites
AU - Vincent, Guillaume A.
AU - de Bruijn, Thomas A.
AU - Wijskamp, Sebastiaan
AU - Abdul Rasheed, Mohammed Iqbal
AU - van Drongelen, Martin
AU - Akkerman, Remko
N1 - Funding Information:
This project was financed by the Dutch Organisation of Applied Research SIA, through the project grant SIA-RAAK 2014-01-72PRO. The authors are grateful to the project partners: Toray Advanced Composites, GKN Fokker, Cato Composite Innovations, Dutch Thermoplastic Components and Nido RecyclingTechniek. The authors are thankful to Sotiris Koussios and Waqas Ali for internal review of the manuscript.
Publisher Copyright:
© 2021 The Author(s)
PY - 2021/1/19
Y1 - 2021/1/19
N2 - A low-shear mixer was used to blend thermoplastic composite scrap material into a molten mixed dough, which was then compression moulded. This process is a key step in a novel recycling solution for thermoplastic composites. A study was carried out to characterise the quality of mixing (QoM) of the blended doughs to understand how to improve the QoM of mixed doughs towards further improvement and implementation of the recycling solution. In order to achieve this, the effect of mixing parameters and fibre length on the QoM were studied. This study used shredded C/PPS flakes, originating from consolidated laminate scrap. These flakes are about 20 mm in size, and contain woven fabric reinforcement, making them far different from regular pellets, and therefore more difficult to mix. The QoM was characterised by means of image analysis of a large set of cross-sectional microscopy images, based on which the scale and intensity of segregation of the fibre clusters were evaluated. Bundle size distribution was determined by applying Delaunay triangulations to cluster the fibre centres. These methods were found to be suitable for characterising the QoM of such doughs. Increasing the mixing time and mixing speed were identified as key ways to improve the mixing process. With the current mixing machine, it is also suggested not to use fibres longer than 15 mm on average in order to limit intra-dough variability. For doughs made of fibres longer than 15 mm, improvements on the mixing device could sufficiently increase the QoM.
AB - A low-shear mixer was used to blend thermoplastic composite scrap material into a molten mixed dough, which was then compression moulded. This process is a key step in a novel recycling solution for thermoplastic composites. A study was carried out to characterise the quality of mixing (QoM) of the blended doughs to understand how to improve the QoM of mixed doughs towards further improvement and implementation of the recycling solution. In order to achieve this, the effect of mixing parameters and fibre length on the QoM were studied. This study used shredded C/PPS flakes, originating from consolidated laminate scrap. These flakes are about 20 mm in size, and contain woven fabric reinforcement, making them far different from regular pellets, and therefore more difficult to mix. The QoM was characterised by means of image analysis of a large set of cross-sectional microscopy images, based on which the scale and intensity of segregation of the fibre clusters were evaluated. Bundle size distribution was determined by applying Delaunay triangulations to cluster the fibre centres. These methods were found to be suitable for characterising the QoM of such doughs. Increasing the mixing time and mixing speed were identified as key ways to improve the mixing process. With the current mixing machine, it is also suggested not to use fibres longer than 15 mm on average in order to limit intra-dough variability. For doughs made of fibres longer than 15 mm, improvements on the mixing device could sufficiently increase the QoM.
KW - Image analysis
KW - Long fibre
KW - Mixing
KW - Spatial statistics
KW - Thermoplastic composites
UR - http://www.scopus.com/inward/record.url?scp=85107028354&partnerID=8YFLogxK
U2 - 10.1016/j.jcomc.2021.100108
DO - 10.1016/j.jcomc.2021.100108
M3 - Article
VL - 4
JO - Composites Part C: Open Access
JF - Composites Part C: Open Access
SN - 2666-6820
M1 - 100108
ER -