Jagannathana D, Adarsha H, Ramaiah K, Prabhud R. A Systematic Study on Mechanical Properties of CNT Reinforced HDPE Composites Developed Using 3D Printing. IJMSE 2023; 20 (3) :1-16
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http://ijmse.iust.ac.ir/article-1-3231-en.html
Abstract: (7735 Views)
Several extensive researches are being carried out in the field of 3D printing. Polymer matrices, such as High-Density Polyethylene (HDPE), are less explored in particular on the microstructure and mechanical properties of HDPE composites developed via Fused Deposition Modelling (FDM) process. Very scarce amount of works is devoted to study HDPE’s reinforced with carbon nano-tubes (CNT’s) . In the present work, we report on the mechanical properties of HDPE composites prepared via FDM process. Varying proportions of CNTs ( 0.5, 1, 1.5 and 2%) are used as reinforcements. It is found that increasing CNT content enhances impact and tensile strength, with HDPE/2.0%CNT outperforming pure HDPE by approximately 71.6% and 25.4%, respectively. HDPE/2.0%CNT composite also showed Young's modulus approximately 49.2% higher than pure HDPE. According to fracture analysis, pure HDPE failed near ductile, whereas composites failed brittle. CNTs occupy the free positions in the polymeric chains, and their tendency to restrict chain mobility causes HDPE to lose ductility and begin to behave brittle. The use of CNTs as reinforcement successfully improved the mechanical properties of HDPE.
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Highlights
Our work aims to find new novelty as bulk amount of research has been carried out using conventional manufacturing techniques for enhanced improvement of mechanical, thermal properties of CNT/HDPE based polymer nanocomposites but the use of latest manufacturing technology by 3D printing (FDM) process has been scarcely reported knowing the advantages of the process.
In this work, HDPE/CNT composites were developed using twin screw extrusion and FDM 3D printing processes. The effect of addition of CNTs in varying weight percentage to the HDPE matrix was evaluated by conducting microstructural, surface roughness, impact, and tensile studies.
- Microstructure analysis using SEM showed uniform dispersion of CNTs and with increase in CNT content revealed no agglomeration. The interfacial bonding between CNT and HDPE matrix was found to be continuous and free from defect.
- Surface roughness studies showed decrease in Ra value as the CNT content was increased in the HDPE composites. The lowest surface roughness was recorded for HDPE/2.0%CNT composite. The reduction in volumetric change in HDPE polymer chains and diminishing of thermal gradients due to presence of CNTs helped the composites to overcome the dimensional inaccuracy related issues which in turn resulted in lower surface roughness values for composites.
- The HDPE composites showed increase in impact and tensile strength with the increase in CNT content. The better dispersion and good interfacial bonding of CNTs with HDPE matrix helped the composite to bear higher loads. The elastic modulus was also found to increase with CNT content with HDPE/2.0%CNT composite showing highest value of 1122.2 MPa.
- The fracture analysis using SEM showed brittle type of failure for all composites while neat HDPE showed ductile fracture. The fracture surface analysis did support the claims of uniform dispersion and alignment of CNTs in the printing direction.