Improvement of mechanical and physical properties of carbon fiber-reinforced polyamide composites by applying different surface coatings for short carbon fiber

2019 ◽  
Vol 33 (4) ◽  
pp. 541-553 ◽  
Author(s):  
Ali Sinan Dike
Keyword(s):  
Carbon Fiber ◽  
Polymer Matrix ◽  
Loss Modulus ◽  
Tensile Modulus ◽  
Mechanical Analysis ◽  
Sem Analysis ◽  
Shore Hardness ◽  
Melt Flow Rate ◽  
Short Carbon Fiber ◽  
Short Carbon

In this study, short carbon fiber (CF) surface was coated with jeffamine, isocyanate, and polyamide (PA). Surface-coated layers of CF samples were confirmed by infrared spectroscopy. Desized and coated CFs were incorporated to PA6 by melt-compounding method with a constant ratio of 20 wt%. Tensile testing, shore hardness, dynamic mechanical analysis (DMA), and melt flow rate (MFR) test of composites were performed. Adhesion of CF to the polymer matrix was investigated by scanning electron microscopy (SEM) of composites. Mechanical characterization of composites implied that tensile strength, tensile modulus, percent elongation, and shore hardness of unfilled PA were extended to higher values by the addition of surface-coated CFs. The highest improvement was observed for isocyanate-modified CF-loaded PA-based composites. According to DMA results, storage modulus and loss modulus of PA increased with the incorporation of sized CF into polymer matrix. CF containing composites showed higher glass transition temperature with respect to unfilled PA. Addition of CF caused no significant change for MFR of PA. Poor adhesion of desized CF and relatively strong adhesion of surface-coated CFs to PA matrix were confirmed by SEM analysis.

scholarly journals High-Performance Polyamide/Carbon Fiber Composites for Fused Filament Fabrication: Mechanical and Functional Performances

2021 ◽  
Author(s):  
Sithiprumnea Dul ◽  
Luca Fambri ◽  
Alessandro Pegoretti
Keyword(s):  
Carbon Fiber ◽  
Tensile Modulus ◽  
Gauge Factor ◽  
Carbon Fiber Composites ◽  
Fused Filament Fabrication ◽  
Resistance Change ◽  
Short Carbon Fiber ◽  
3D Printed ◽  
The Impact ◽  
Short Carbon

AbstractThis study is focused on the 3D printing by fused filament fabrication (FFF) process of short carbon-fiber-reinforced polyamide (PA) composites. In particular, the effect of short carbon fiber (CF) on the mechanical, electrical and piezoresistivity properties of 3D-printed polyamide (PA) composite parts has been analyzed. In comparison with neat PA, the results revealed that the carbon fibers effectively improved all assessed mechanical properties of PA/CF composites. In particular, in XY build orientation, PA/CF 3D-printed composites exhibited a tensile strength of 96 MPa and a tensile modulus of 7.9 GPa, with an increment of + 34 and + 147%, respectively, when compared to the neat PA. Interlayer strength of 3D-printed PA and PA/CF composites reaches similar values, in the range 26-28 MPa. The impact strength of 3D-printed XY parts was reduced by the presence of CF. However, the fracture toughness of PA/CF composite 3D-printed parts was slightly higher in comparison with that of neat PA. Electrical resistivity of PA/CF 3D-printed parts is gradually decreasing from 1.7 × 104 to 0.7 × 104 Ω cm in the temperature range from − 16 to 100 °C. The piezoresistivity tests revealed that an exponential resistance change occurs for both compression-molded and 3D-printed PA/CF samples once strained in tension. A gauge factor of 3D-printed parts of about 65 ± 5 was determined from cyclic strains in the elastic region.

scholarly journals Ductile to Brittle Transition of Short Carbon Fiber-Reinforced Polypropylene Composites

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Harri Junaedi ◽  
Essam Albahkali ◽  
Muneer Baig ◽  
Abdulsattar Dawood ◽  
Abdulhakim Almajid
Keyword(s):  
Carbon Fiber ◽  
Tensile Modulus ◽  
Short Carbon Fiber ◽  
Polypropylene Composites ◽  
Brittle Transition ◽  
Twin Screw ◽  
Injection Molded ◽  
Ductile To Brittle Transition ◽  
Sudden Decrease ◽  
Short Carbon

In this work, the ductile to brittle transition behavior of short carbon fiber (SCF)-reinforced polypropylene (PP) composite is studied. Initially, the SCF-reinforced PP composites with a varying composition of SCF in the range of 0–40 wt% loading were first melt-mixed in a twin-screw extruder and later injection-molded to produce the testing samples. The experimental results indicate that with an increase in SCF loading, an increase in the tensile modulus and strength was observed along with a rapid decrease in the values of strain at break. A sudden decrease in strain at break was observed in composites in the range of 10–15 wt% SCF. To further study the sudden decrease in strain at break, an investigation was performed on composites that contained 10–15 wt% of SCF loading, starting from 10 wt% with a 1% increment to 15 wt% of SCF. The results of this study show that a decrease in strain at break was not linear; on the contrary, it was accompanied by a ductile to brittle transition, which specifically occurred in the range of 12–13 wt% of SCF loading and then continued to decrease with an increase in SCF loading.

scholarly journals Effect of Geometric Parameters and Moisture Content on the Mechanical Performances of 3D-Printed Isogrid Structures in Short Carbon Fiber-Reinforced Polyamide

2021 ◽  
Author(s):  
Valerio Di Pompeo ◽  
Archimede Forcellese ◽  
Tommaso Mancia ◽  
Michela Simoncini ◽  
Alessio Vita
Keyword(s):  
Carbon Fiber ◽  
Moisture Content ◽  
Geometric Parameters ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Short Carbon Fiber ◽  
3D Printed ◽  
Carbon Fiber Reinforced ◽  
Mechanical Performances ◽  
Short Carbon

AbstractThe present paper aims at studying the effect of geometric parameters and moisture content on the mechanical performances of 3D-printed isogrid structures in short carbon fiber-reinforced polyamide (namely Carbon PA). Four different geometric isogrid configurations were manufactured, both in the undried and dried condition. The dried isogrid structures were obtained by removing the moisture from the samples through a heating at 120 °C for 4 h. To measure the quantity of removed moisture, samples were weighted before and after the drying process. Tensile tests on standard specimens and buckling tests on isogrid panels were performed. Undried samples were tested immediately after 3D printing. It was observed that the dried samples are characterized by both Young modulus and ultimate tensile strength values higher than those provided by the undried samples. Similar results were obtained by the compression tests since, for a given geometric isogrid configuration, an increase in the maximum load of the dried structure was detected as compared to the undried one. Such discrepancy tends to increase as the structure with the lowest thickness value investigated is considered. Finally, scanning electron microscopy was carried out in order to analyze the fractured samples and to obtain high magnification three-dimensional topography of fractured surfaces after testing.

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