Research on Mechanical Properties and Internal Structures of Discontinuous Recycled CF/PA6 Composites with Various Molding Conditions
Topic(s) : Special Sessions
Co-authors :
Qiujun WANG (JAPAN), Qian GAO , Yi WAN , Jun TAKAHASHI (JAPAN)Abstract :
With superior mechanical properties and high strength-to-weight ratio, carbon fiber-reinforced plastics (CFRPs) have been widely applied to various industries. However, the expending global market and increasing demand of CFRPs have raised growing concerns regarding the management and strategies for dealing with production-related or end-of-life carbon fiber (CF) waste. Several chemical and thermal techniques have been reported for CF recycling, allowing for CF reuse without significant degradation in properties [1]. Subsequently, re-manufacturing processes, such as the carding process, become necessary for applying to recycled CFs (rCFs) to reduce CF waste accumulation and bring closure to the lifecycle of CFRP materials [2].
Considering the importance and potential applications of the carding process in re-manufacturing of rCFs, this research aims to investigate the internal structures and mechanical properties of discontinuous rCF/PA6 composites fabricated of rCF carded nonwoven mats under different molding conditions, to provide a crucial reference for future applications. In this research, CFs were recycled from the pyrolysis process at first, and were then manufactured into nonwoven mats through the carding process. The mat was then cut into 250×125 mm sheets in both machine and cross directions, stacked with a specific quantity of polyamide 6 (PA6) resin films to achieve the targeted fiber volume fractions of 30%, 35%, and 40%. Finally, the stacked sheets were molded to form rCF/PA6 composites under temperature of 265°C and pressures of 8 MPa, 9 MPa and 10 MPa.
The mechanical properties of the composite were evaluated through the implementation of tensile and three-point bending tests. The rCF/PA6 composites with an actual fiber volume fraction of 39%, shows notable mechanical properties, with a tensile and flexural strength of 493.08 MPa and 622.39 MPa, and a tensile and flexural modulus of 48.75 GPa and 43.53 GPa. Furthermore, Scanned by X-ray micro-CT, the internal structures of rCF/PA6 composites could be observed, and image data with dimension of 1×1×1 mm were extracted for fiber orientation distribution (FOD) analysis. Utilizing findings from the FOD analysis, this study delves into the influence of molding pressure on the internal structures, subsequently examining its impact on mechanical properties across varying molding conditions. Finite element model was finally established based on the experimental conditions, and the uncertainties generated by Monte-Carlo simulation was integrated to the model to predict the mechanical properties of the composites.
In summary, the carding process emerges as an efficacious approach for the reusing of rCFs, and the present study endeavors to elucidate its viability within the domain of recycling and re-manufacturing.
Considering the importance and potential applications of the carding process in re-manufacturing of rCFs, this research aims to investigate the internal structures and mechanical properties of discontinuous rCF/PA6 composites fabricated of rCF carded nonwoven mats under different molding conditions, to provide a crucial reference for future applications. In this research, CFs were recycled from the pyrolysis process at first, and were then manufactured into nonwoven mats through the carding process. The mat was then cut into 250×125 mm sheets in both machine and cross directions, stacked with a specific quantity of polyamide 6 (PA6) resin films to achieve the targeted fiber volume fractions of 30%, 35%, and 40%. Finally, the stacked sheets were molded to form rCF/PA6 composites under temperature of 265°C and pressures of 8 MPa, 9 MPa and 10 MPa.
The mechanical properties of the composite were evaluated through the implementation of tensile and three-point bending tests. The rCF/PA6 composites with an actual fiber volume fraction of 39%, shows notable mechanical properties, with a tensile and flexural strength of 493.08 MPa and 622.39 MPa, and a tensile and flexural modulus of 48.75 GPa and 43.53 GPa. Furthermore, Scanned by X-ray micro-CT, the internal structures of rCF/PA6 composites could be observed, and image data with dimension of 1×1×1 mm were extracted for fiber orientation distribution (FOD) analysis. Utilizing findings from the FOD analysis, this study delves into the influence of molding pressure on the internal structures, subsequently examining its impact on mechanical properties across varying molding conditions. Finite element model was finally established based on the experimental conditions, and the uncertainties generated by Monte-Carlo simulation was integrated to the model to predict the mechanical properties of the composites.
In summary, the carding process emerges as an efficacious approach for the reusing of rCFs, and the present study endeavors to elucidate its viability within the domain of recycling and re-manufacturing.