Effect of carbon nanotubes modified with different concentrations of rare earth lanthanum on the mechanical and tribological properties of epoxy composites

2021 ◽  
pp. 002199832098764
Author(s):  
Mingren Jiang ◽  
Xianhua Cheng

Rare earth modified acidified carbon nanotubes were prepared by functionalization of acidified carbon nanotubes with different concentrations of LaCl3. The modification results were characterized by Fourier-transform infrared and X-ray photoelectron spectroscopy. The rare earth successfully increases the surface activity of the acidified carbon nanotubes. Polymer matrix composites were prepared by using the rare earth modified acidified carbon nanotubes as the reinforcement in epoxy matrix. Mechanical properties were analyzed by Zwick Z100 testing machine and the tribological behaviors were test by multifunctional tribological tester. Compared with pure epoxy (epoxy resin), the mechanical strength of the best composite sample was increased by 50–120%, the coefficient of friction was reduced by 19.4% and the wear rate was reduced by approximately 40 times. The experimental results show that the RE concentration of 0.2–0.3 wt% has the most obvious influence on the properties of polymer composites. The mechanism of rare earth reinforcement in polymer matrix is analyzed and suggested.

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
R. Raghavendra Rao ◽  
S. Pradeep ◽  
Nasim Hasan ◽  
B. S. Shivashankara ◽  
Mohamed Abdelghany Elkotb ◽  
...  

In comparison to conventional materials, polymer matrix composite materials have witnessed a surge in applicability due to their higher specific strength-to-weight ratio, abundant availability, and ease of shaping. Due to technological, economic, environmental, and societal challenges, bio-based fibers began to emerge quickly for use in industrial components. Due to its unique chemistry-related characteristics, basalt fiber holds a prominent position among the many bio-based fibers. So, it could be thought of used as a replacement for some components used in the biomedical equipments. In the present investigation, plain-woven basalt fiber at a constant percentage of 55% is added as reinforcement to three different epoxy resin-hardener combinations such as Lapox L12-Lapox K6, Araldite LY1564-Aradur 22962, and Araldite LY556-Aradur HY951 as matrix, and comparative studies are carried out. Fabrication is carried out by hand lay-up technique. Test specimens are prepared as per the respective ASTM standards by subjecting the laminate to water jet machining. Mechanical characterization such as tensile, flexural, and density tests is conducted for the test specimen using BISS-50 kN Universal Testing Machine (UTM). Water absorption tests are also conducted for 24 and 48 hours duration. From the results obtained, it is concluded that the highest tensile, flexural strengths are obtained for laminate L3 which used LY556 epoxy and HY951 hardener combination as matrix. Also, less rate of water absorption is seen for L3 laminate for both 24 and 48 hrs which makes it suitable for biomedical applications.


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