Thermal Property Measurement of Thin Fibers: A Direct Approach

Author(s):  
Troy Munro ◽  
Changhu Xing ◽  
Heng Ban ◽  
Cameron Copeland ◽  
Randolph Lewis ◽  
...  

Fiber thermal characterization is often accomplished by indirect means, such as embedding the fiber in a matrix, measuring the thermal response of the composite, and relating for the contributions of the fiber and matrix to the overall behavior or measuring bundles of fibers. To improve the accuracy of the composite-based or bundle-based techniques, several different contact (hot wire and dc thermal bridge) and non-contact (Raman shift and IR thermography) methods have been developed to directly measure the thermal properties of individual fibers. To improve on the shortcomings of these methods, this paper presents the experimental results of an improved transient electrothermal (TET) method, as well as a 3ω-based method that better accounts for all sources of heat transfer, particularly heat loss by radiation. The incorporation of radial radiation heat loss becomes a significant factor as the size of the fibers decrease. This work describes practical applications of the methods to measure the properties of the fibers, including sample preparation for electrically conductive and non-conductive samples, data acquisition and calibration, data analysis, and sample property determination. Results include validation of the methods with electrically conductive (platinum) and non-conductive (glass) fibers to improve upon the initial validation of the generalized electrothermal method which focused only on short, conductive fibers. The axial thermal conductivity and diffusivity of several high performance fibers are presented. The novelty of this paper is that it serves as both a compilation of previous research on the transient electrothermal and 3ω methods [1–6], measurements of new silk fibers, and practical information associated with the methods that improve the accuracy of the measured thermal property, as well as presenting thermal properties of additional fibers (carbon fiber and natural and synthetic spider silks). To improve upon the long sample preparation time required for the TET and 3ω methods, future work focused on the development of a quantum dot-based photothermal fluorescence method is presented.

2006 ◽  
Vol 532-533 ◽  
pp. 333-336 ◽  
Author(s):  
Bok Choon Kang ◽  
Chathura Nalendra Herath ◽  
Jong Kwang Park ◽  
Yong Hwang Roh

Carbon, aramid and glass fibers are inherently superior to conventional textile fibers in terms of mechanical properties and other characteristics. However, each material has its inherent advantages and disadvantages and it is usually recommended to hybridize them to fully benefit of their high performance in practical applications to many products. This paper is concerned with an air texturing process for hybridization of different reinforcement filament yarns. A normal air texturing machine was selected for process development and modified to suit testing purposes. The modified process for hybridization was introduced mainly in terms of air-jet nozzles employed in experiments. With the proposed air texturing process machine, three types of air-nozzle were applied to the experimental work. Three different filament materials were employed in experiments and they are carbon (CF), aramid (AF), and glass (GF). As matrix materials, polyether-ether (PEEK), polyester (PES), and polypropylene (PP) were selected and experimented. Hybrid yarns produced form the proposed process was evaluated optically in terms of bulkiness, arranging, breaking, and mixing, respectively. The experimental results were also summarized in terms of relationships between applied air pressure and yarn count, and variation in count. As a whole, it was concluded from the experiments that the proposed texturing process could be successfully applied to the practical hybridization of different reinforcement filament yarns. It was also revealed from the experiments that the air pressure in the proposed process is not a significant parameter on the pressing in terms of yarn count.


2018 ◽  
Vol 31 (6) ◽  
pp. 719-732 ◽  
Author(s):  
Abdeldjalil Zegaoui ◽  
Mehdi Derradji ◽  
Abdul Qadeer Dayo ◽  
Aboubakr Medjahed ◽  
Hui-yan Zhang ◽  
...  

The investigation and design of new polymeric materials with an astonishing combination of properties are nowadays of great importance to facilitate the manufacturing process of high-quality products intended to be utilized in different applications and technical fields. For this intent, novel high-performance blend composites composed of the cyanate ester/benzoxazine resin blend reinforced by different proportions of silane-surface modified Kevlar and glass fibers were successfully fabricated by a compression molding technique and characterized by different experimental tests. The mechanical test results revealed that the bending and impact strength properties were considerably improved when increasing the amount of the hybrid fibers. The studied materials also presented excellent thermal stabilities as compared to the unfilled blend’s properties. With respect to the properties of the reinforcing systems, these improvements seen in either the mechanical or thermal properties could be due to the good dispersion as well as excellent adhesion of the reinforcing fibers inside the resin matrix, which were further evidenced by the Fourier transform infrared spectroscopy and scanning electron microscopy results. Consequently, the improved mechanical and thermal properties promote the use of the fabricated hybrid composites in domestic and industrial applications requiring functional materials with advanced properties for aerospace and military applications.


2007 ◽  
Vol 539-543 ◽  
pp. 974-978
Author(s):  
Chathura Nalendra Herath ◽  
Beong Bok Hwang ◽  
B.S. Ham ◽  
Jung Min Seo ◽  
Bok Choon Kang

Carbon, aramid and glass fibers are inherently superior to conventional textile fibers in terms of mechanical properties as well as other chemical characteristics. Because of inherent advantages and disadvantages associated with each material, it is generally better to hybridize them to fully benefit of their high performance in many practical applications. In this paper, the possibility of hybridizing Carbon/Aramid-, Carbon/Glass- and Aramid/Glass- matrices has been investigated through the commingling process. In the experiment, several process parameters were selected and they include pressure, yarn oversupply-rate and different nozzle types. As a result of experiments, it was concluded that the hybridized materials has shown better performance than individual reinforced filament yarns in terms of mechanical properties. For small tensile forces, the Carbon/Glass/matrix combination turned out to be good enough for general purpose applications. However, for high tensile applications, Carbon/Aramid or Aramid/Glass with matrix combinations was better than the other material combinations. The hybridization process was also investigated under an air pressure of 5 bar, a yarn oversupply-rate of 1.5% for reinforced filaments, and 3.5% to 6% for matrix materials, respectively. It was also shown from the experimental results that Carbon/Glass/matrix combination may be desirable for small tensile force applications and Carbon/Aramid/matrix and Glass/Aramid/matrix combinations most suitable for heavy tensile force applications, respectively. As a matrix material, polypropylene and polyester have shown better performance than polyether-ether-keeton in terms of tensile property.


2014 ◽  
Vol 529 ◽  
pp. 97-101
Author(s):  
Fabrizia Ghezzo ◽  
Xi Geng Miao ◽  
Ruo Peng Liu

The effect of the presence of fillers on the thermal properties of a high performance elastomer was investigated in this work. The characterization of the specific heat capacity (Cp), the specific heat flow and the glass transition temperature of a polyurea elastomer reinforced with two different classes of fillers, i.e. short glass fibers and alumina nanoparticles, was conducted by using a differential scanning calorimeter (DSC). We present and discuss the results of the experimental characterization carried out on the reinforced material. The results are compared to those obtained by testing the pure polymer.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 235
Author(s):  
Shuqi Zhao ◽  
Tongtong Yu ◽  
Ziming Wang ◽  
Shilei Wang ◽  
Limei Wei ◽  
...  

Two-dimensional (2D) materials driven by their unique electronic and optoelectronic properties have opened up possibilities for their various applications. The large and high-quality single crystals are essential to fabricate high-performance 2D devices for practical applications. Herein, IV-V 2D GeP single crystals with high-quality and large size of 20 × 15 × 5 mm3 were successfully grown by the Bi flux growth method. The crystalline quality of GeP was confirmed by high-resolution X-ray diffraction (HRXRD), Laue diffraction, electron probe microanalysis (EPMA) and Raman spectroscopy. Additionally, intrinsic anisotropic optical properties were investigated by angle-resolved polarized Raman spectroscopy (ARPRS) and transmission spectra in detail. Furthermore, we fabricated high-performance photodetectors based on GeP, presenting a relatively large photocurrent over 3 mA. More generally, our results will significantly contribute the GeP crystal to the wide optoelectronic applications.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Myungwoo Son ◽  
Jaewon Jang ◽  
Yongsu Lee ◽  
Jungtae Nam ◽  
Jun Yeon Hwang ◽  
...  

AbstractHere, we demonstrate the fabrication of a Cu-graphene heterostructure interconnect by the direct synthesis of graphene on a Cu interconnect with an enhanced performance. Multilayer graphene films were synthesized on Cu interconnect patterns using a liquid benzene or pyridine source at 400 °C by atmospheric pressure chemical vapor deposition (APCVD). The graphene-capped Cu interconnects showed lower resistivity, higher breakdown current density, and improved reliability compared with those of pure Cu interconnects. In addition, an increase in the carrier density of graphene by doping drastically enhanced the reliability of the graphene-capped interconnect with a mean time to failure of >106 s at 100 °C under a continuous DC stress of 3 MA cm−2. Furthermore, the graphene-capped Cu heterostructure exhibited enhanced electrical properties and reliability even if it was a damascene-patterned structure, which indicates compatibility with practical applications such as next-generation interconnect materials in CMOS back-end-of-line (BEOL).


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2455
Author(s):  
Jiayuan He ◽  
Weizhen Chen ◽  
Boshan Zhang ◽  
Jiangjiang Yu ◽  
Hang Liu

Due to the sharp and corrosion-prone features of steel fibers, there is a demand for ultra-high-performance concrete (UHPC) reinforced with nonmetallic fibers. In this paper, glass fiber (GF) and the high-performance polypropylene (HPP) fiber were selected to prepare UHPC, and the effects of different fibers on the compressive, tensile and bending properties of UHPC were investigated, experimentally and numerically. Then, the damage evolution of UHPC was further studied numerically, adopting the concrete damaged plasticity (CDP) model. The difference between the simulation values and experimental values was within 5.0%, verifying the reliability of the numerical model. The results indicate that 2.0% fiber content in UHPC provides better mechanical properties. In addition, the glass fiber was more significant in strengthening the effect. Compared with HPP-UHPC, the compressive, tensile and flexural strength of GF-UHPC increased by about 20%, 30% and 40%, respectively. However, the flexural toughness indexes I5, I10 and I20 of HPP-UHPC were about 1.2, 2.0 and 3.8 times those of GF-UHPC, respectively, showing that the toughening effect of the HPP fiber is better.


2021 ◽  
pp. 095400832110130
Author(s):  
Hailong Li ◽  
Sipei Zhao ◽  
Li Pei ◽  
Zihe Qiao ◽  
Ding Han ◽  
...  

Polybenzoxazines are emerging as a class of high-performance thermoset polymers that can find their applications in various fields. However, its practical application is limited by its low toughness. The cyclic β-cyclodextrin and a newly synthesized derivative (β-cyclodextrin-MAH) were separately blended with benzoxazine to improve the toughness of polybenzoxazine. The results revealed that the maximum impact strength of the blend was 12.24 kJ·m−2 and 14.29 kJ·m−2 when 1 wt.% of β-Cyclodextrin and β-Cyclodextrin-MAH, respectively, were used. The strengths were 53% and 86% higher than that of pure polybenzoxazine. The curing reaction, possible chemical structures, and fractured surface were examined using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques to understand the mechanism of generation of toughness. The results revealed that the sea-island structure and the presence of hydrogen bonds between polybenzoxazine and β-cyclodextrin and β-cyclodextrin-MAH resulted in the generation of toughness. Furthermore, the curves generated during thermogravimetric analysis did not significantly change, revealing the good thermal properties of the system. The phase-separated structure and the hydrogen bonds present in the system can be exploited to prepare synergistically tough polybenzoxazine exhibiting excellent thermal properties. This can be a potential way of modifying the thermoset resins.


Sign in / Sign up

Export Citation Format

Share Document