Carbon fiber reinforced carbon aerogel composites for thermal insulation prepared by soft reinforcement

2012 ◽  
Vol 67 (1) ◽  
pp. 266-268 ◽  
Author(s):  
Junzong Feng ◽  
Changrui Zhang ◽  
Jian Feng
2017 ◽  
Vol 36 (23) ◽  
pp. 1745-1755 ◽  
Author(s):  
Tsung-Han Hsieh ◽  
Yau-Shian Huang ◽  
Ming-Yuan Shen

Carbon aerogels are a promising candidate for vibration insulation due to their three-dimensional networked structures interconnected with carbon nanoparticles. However, the effect of adding carbon aerogels to polymer-based composites on their dynamic properties remains unclear. In this study, an epoxy polymer matrix was modified with carbon aerogels, and this modified matrix was used to manufacture nanocomposite plates and carbon fiber-reinforced polymer composite laminates to investigate its dynamic properties. Force vibration tests were performed on cantilever beams of the composite beams. The frequency responses of the composite beams were measured experimentally and analytically; the half-power method was used to calculate the damping ratio for each vibration mode. According to the experimental results, the presence of carbon aerogel in the nanocomposites and laminates steadily increased the natural frequencies. Differences within 10% of the natural frequencies were obtained between the experimental and numerically. Furthermore, the damping ratios of the nanocomposite and laminate beams increased significantly with the increase in aerogel loading. For a nanocomposite with 0.3 wt% aerogel, a damping ratio approximately 44% greater than that of unmodified nanocomposite was obtained. The maximum damping ratio was 4.682% for the laminate with 0.5 wt% aerogel—an 88% increase compared with the unmodified laminate.


Author(s):  
Hong-Ming Lin ◽  
C. H. Liu ◽  
R. F. Lee

Polyetheretherketone (PEEK) is a crystallizable thermoplastic used as composite matrix materials in application which requires high yield stress, high toughness, long term high temperature service, and resistance to solvent and radiation. There have been several reports on the crystallization behavior of neat PEEK and of CF/PEEK composite. Other reports discussed the effects of crystallization on the mechanical properties of PEEK and CF/PEEK composites. However, these reports were all concerned with the crystallization or melting processes at or close to atmospheric pressure. Thus, the effects of high pressure on the crystallization of CF/PEEK will be examined in this study.The continuous carbon fiber reinforced PEEK (CF/PEEK) laminate composite with 68 wt.% of fibers was obtained from Imperial Chemical Industry (ICI). For the high pressure experiments, HIP was used to keep these samples under 1000, 1500 or 2000 atm. Then the samples were slowly cooled from 420 °C to 60 °C in the cooling rate about 1 - 2 degree per minute to induce high pressure crystallization. After the high pressure treatment, the samples were scanned in regular DSC to study the crystallinity and the melting temperature. Following the regular polishing, etching, and gold coating of the sample surface, the scanning electron microscope (SEM) was used to image the microstructure of the crystals. Also the samples about 25mmx5mmx3mm were prepared for the 3-point bending tests.


2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.


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