scholarly journals A Preliminary Study of the Influence of Graphene Nanoplatelet Specific Surface Area on the Interlaminar Fracture Properties of Carbon Fiber/Epoxy Composites

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3060
Author(s):  
Konstantina Zafeiropoulou ◽  
Christina Kostagiannakopoulou ◽  
George Sotiriadis ◽  
Vassilis Kostopoulos

Graphene nanoplatelets (GNPs) are of particular interest to the field of nano-reinforced composites since they possess superior mechanical, fracture, thermal, and barrier properties. Due to their geometrical characteristics, high aspect ratio (AR)/specific surface area (SSA) and their planar structure, GNPs are considered as high-potential nanosized fillers for improving performance of composites. The present study investigates the effect of SSA of GNPs on fracture properties of carbon fiber reinforced polymers (CFRPs). For this reason, two nano-doped CFRPs were produced by using two types of GNPs (C300 and C500) with different SSAs, 300 and 500 m2/g, respectively. Both types of GNPs, at the same content of 0.5 wt%, were added into the epoxy matrix of composites by applying a three-roll milling technique. The nanomodified matrix was used for the manufacturing of prepregs, while the final composite laminates were fabricated through the vacuum-bag method. Mode I and II interlaminar fracture tests were carried out to determine the interlaminar fracture toughness GIC and GIIC of the composites, respectively. According to the results, the toughening effect of C500 GNPs was the strongest, resulting in increases of 25% in GIC and 33% in GIIC compared with the corresponding unmodified composites. The activation of the absorption mechanisms of C500 contributed to this outcome, which was confirmed by the scanning electron microscopy (SEM) analyses conducted in the fracture surfaces of specimens. On the other hand, C300 GNPs, due to disability to be dispersed uniformly into the epoxy matrix, did not influence the fracture properties of CFRPs, indicating that probably there is a threshold in SSA which is necessary to achieve for improving the fracture properties of CFRPs.

2021 ◽  
pp. 002199832110492
Author(s):  
Kimiyoshi Naito ◽  
Chiemi Nagai

The mode-I and mode-II interlaminar fracture properties of high modulus pitch-based carbon fiber reinforced polymers (CFRPs) (fiber: K13C; resin: EX-1515 cyanate ester) modified with 20–30 nm β-SiC nanoparticles or multiwalled-carbon nanotubes (MWCNTs) were investigated. Different volume fractions of both the β-SiC nanoparticles (1, 2, 5, and 10 vol%) and MWCNTs (1, 3, 5, and 7 vol%) were tested. The values of the mode-I and mode-II interlaminar fracture toughness of the CFRPs containing the lowest volume fractions of these nanostructures were larger compared with the unfilled composite but decreased with increasing the volume fraction of the inclusions. No differences in mechanical properties were observed among the different nanostructure types.


2012 ◽  
Vol 209-211 ◽  
pp. 1990-1994 ◽  
Author(s):  
Qin Zhang ◽  
Zhao Hui Zhang ◽  
Liang Wang ◽  
Zi Long Zhang ◽  
Xing Fei Guo

The properties of four different activated carbon fiber cloth (ACF), such as specific surface area, pore volumes and pore size distribution, were evaluated. The relationship between ACF properties and its electrosorption performance was analyzed. The experimental results show that pore structure has more influence on the performance of ACF electrode than that of specific surface area for ACF material. More abundant mesopores and shallower pore channels for ACF is favorable to improve the specific capacitance and electrosorption capacity of ions.


2020 ◽  
Vol 42 (6) ◽  
pp. 289-297
Author(s):  
Eunbyul Lee ◽  
Jonggu Kim ◽  
Byungtae Yoo

Objectives:A paper filter was prepared by pitch based activated carbon fibers to investigate the removal efficiency of toxic gas. Also, changes in pore characteristics and mechanical properties according to the ratio of the adsorbent and the binder were observed to optimize the decrease in specific surface area and micropore, which are the unique characteristics of activated carbon fibers. In addition, it is intended to establish optimized paper filter derived activated carbon fiber manufacturing conditions through evaluation of toxic gas removal characteristics.Methods:The pore characteristics of the activated carbon fiber and prepared paper were analyzed by measuring the BET specific surface area, and SEM analysis was performed on the fine surface shape. Tensile strength and air permeability were performed according to ISO 1924-2 and ASTM D737: 04, respectively. The adsorption performance of the prepared filter was evaluated as a gas removal efficiency using a gas detection tube (GV-110S).Results and Discussion:As the content of the binder increased in the paper manufacturing process, it was confirmed that the specific surface area of ​​the prepared filter decreased by up to 39.5% compared to the activated carbon fiber. It is considered that the micropores were closed because the surface of the activated carbon fiber was coated with the excessive addition of the binder. The removal efficiency showed a removal rate of 90% of ammonia, and methyl mercaptan and hydrogen sulfide showed a removal rate of about 60%. This result might be due to the difference in the physical adsorption rate according to the vapor pressure of each material.Conclusions:An activated carbon fiber-based paper filter for removing of toxic gas was prepared. It was confirmed that the mixing ratio of the adsorbent and the binder was an important process parameter for determining moldability and adsorption performance. Finally, optimum condition was selected as weight ratio condition of 8:2.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6367
Author(s):  
Shu Xiong ◽  
Yan Zhao ◽  
Jiupeng Song

The surface roughness (Ra) and composite interfacial property of carbon fiber (CF) are considered to be mainly affected by the microstructure of the CF surface. However, quantitative characterization of the CF surface microstructure is always a difficulty. How the CF surface microstructure affects the interfacial property of CF composites is not entirely clear. A quantitative characterization technique based on images was established to calculate the cross-section perimeter and area of five types of CFs, as well as the number (N), width (W) and depth (D) of grooves on these CF surfaces. The CF composite interfacial shear strength (IFSS) was tested by the micro-droplet debonding test and modified by the realistic perimeter. The relationship between the groove structure parameter and the Ra, specific surface area and composite interfacial property was discussed in this article. The results indicated that the CF cross-section perimeter calculated by this technique showed strong consistency with the CF specific surface area and composite interfacial property. At last, the composite interface bonding mechanism based on defect capture was put forward. This mechanism can be a guiding principle for CF surface modification and help researchers better understand and establish interface bonding theories.


2011 ◽  
Vol 480-481 ◽  
pp. 6-10
Author(s):  
Yan Feng Yang ◽  
Xue Jun Zhang ◽  
Hai Yan Li

General purpose pitch-based carbon fiber (PCF) was pretreated with steam to develop pores on the surface of fiber. After immersed in cobalt salt solution, PCF was used as raw materials to prepare activated carbon fiber (ACF) through steam activation process. The effect of pretreatment of carbon fiber on specific surface area, mesopore volume and pore size distribution was investigated by N2 adsorption, and morphology of the resultant ACF was observed with scanning electron microscope(SEM). The results show that pretreatment of PCF enlarges specific surface area and mesopore ratio of ACF remarkably. The best ACF obtained in experiment is the one with specific surface area of 2670 m2/g and mesoporosity of 61.8%. Cobalt has evident catalysis in preparing ACF from activation of PCF, while specific surface area and pore size of ACF get smaller with cobalt salt immersion when pretreatment is too strong.


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