Large scale fabrication of dumbbell-shaped biomimetic SiC/SiO2 fibers

CrystEngComm ◽  
2015 ◽  
Vol 17 (48) ◽  
pp. 9318-9322 ◽  
Author(s):  
Wenna Liu ◽  
Junhong Chen ◽  
Kuo-Chih Chou ◽  
Xinmei Hou

The mechanical properties of dumbbell-shaped fiber-reinforced composites are expected to be improved via enhancing the interface adhesion between the matrix and the fibers from the viewpoint of biomimetics.

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 842 ◽  
Author(s):  
Weiwei Zhang ◽  
Jin Gu ◽  
Dengyun Tu ◽  
Litao Guan ◽  
Chuanshuang Hu

Paper fibers have gained broad attention in natural fiber reinforced composites in recent years. The specific problem in preparing paper fiber reinforced composites is that paper fibers easily become flocculent after pulverization, which increases difficulties during melt-compounding with polymer matrix and results in non-uniform dispersion of paper fibers in the matrix. In this study, old newspaper (ONP) was treated with a low dosage of gaseous methyltrichlorosilane (MTCS) to solve the flocculation. The modified ONP fibers were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TG). Then the modified ONP fibers and high-density polyethylene (HDPE) were extruded and pelletized to prepare ONP/HDPE composites via injection molding. Maleic anhydride-grafted polyethylene (MAPE) was added to enhance the interfacial bonding performance with the ultimate purpose of improving the mechanical strength of the composites. The mechanical properties such as tensile, flexural, and impact strength and the water absorption properties of the composite were tested. The results showed that the formation of hydrogen bonding between ONP fibers was effectively prevented after MTCS treatment due to the reduction of exposed –OH groups at the fiber surface. Excessive dosage of MTCS led to severe fiber degradation and dramatically reduced the aspect ratio of ONP fibers. Composites prepared with ONP fibers modified with 4% (v/w) MTCS showed the best mechanical properties due to reduced polarity between the fibers and the matrix, and the relatively long aspect ratio of treated ONP fibers. The composite with or without MAPE showed satisfactory water resistance properties. MTCS was proven to be a cheap and efficient way to pretreat old newspaper for preparing paper fiber reinforced composites.


2020 ◽  
pp. 002199832094964
Author(s):  
Mojde Biarjemandi ◽  
Ehsan Etemadi ◽  
Mojtaba Lezgy-Nazargah

Recent researches show that the embedment of hollow spheres in the matrix phase of composite materials improves the strength of these structures against crack propagations. Rare studies are reported for calculating equivalent elastic constants of fiber reinforced composites containing hollow spheres. In this paper, the effects of hollow spheres on mechanical characteristics of fiber reinforced composite are studied for the first time. To achieve this aim, a micromechanics based finite element method is employed. Representative volume elements (RVEs) including hollow spheres with different radius, thickness and volume fraction of hollow spheres, are modeled by using 3D finite elements. The equivalent elastic constants are calculated through homogenization technique. The results are compared with available experimental works. Good agreements find between two sets of results. Also, the volume fraction, number and thickness of hollow spheres as effective parameters on mechanical properties of composite were investigated. The results show the equivalent elastic properties increase with increasing the volume fraction and number of hollow spheres and decrease with increasing the number of hollow spheres. Furthermore, the equivalent Young’s modulus in transverse directions to the fiber direction and shear modulus of the composite increase with increasing the thickness of hollow spheres. As a final result, the presence of hollow spheres in the matrix phase generally increases the equivalent elastic constants without significant changes in the weight of structures.


2020 ◽  
Vol 22 (1) ◽  
pp. 295-300 ◽  
Author(s):  
A. Francis ◽  
S. Rajaram ◽  
A. Mohanakrishnan ◽  
B. Ashok

AbstractThe composite materials plays a vital role in increase the strength and weight reduction purpose. The natural fibers increase the additional strength to the composites. This paper is related to the mechanical properties of the sisal fiber reinforced composites and it is compared with the another preparation of sisal fiber reinforced composite. The graphs shows the comparison about the mechanical properties on the fiber reinforced composites. The strength can be improved by using some melted polypropylene to increase the bonding between the matrix and the fiber. The sample material is immersed in water for twenty four hours and at the same time the properties also measured by using various testing methods. The final comparison indicates the better process for the preparation of the composite.


2012 ◽  
Vol 06 ◽  
pp. 646-651 ◽  
Author(s):  
Wen Ma ◽  
Fushun Liu

Voids are inevitable in the fabrication of fiber reinforced composites and have a detrimental impact on mechanical properties of composites. Different void contents were acquired by applying different vacuum bag pressures. Ultrasonic inspection and ablation density method were adopted to measure the ultrasonic characteristic parameters and average porosity, the characterization of voids' distribution, shape and size were carried out through metallographic analysis. Effects of void content on the tensile, flexural and interlaminar shear properties and the ultrasonic characteristic parameters were discussed. The results showed that, as vacuum bag pressure went from -50kPa to -98kPa, the voids content decreased from 4.36 to 0.34, the ultrasonic attenuation coefficient decreased, but the mechanical strengths all increased.


2012 ◽  
Vol 510-511 ◽  
pp. 577-584 ◽  
Author(s):  
A. Quddos ◽  
Mohammad Bilal Khan ◽  
R.N. Khan ◽  
M.K.K. Ghauri

The impregnation of the fiber with a resin system, the polymeric matrix with the interface needs to be properly cured so that the dimensional stability of the matrix and the composite is ensured. A modified epoxy resin matrix was obtained with a reactive toughening agent and anhydride as a curing agent. The mechanical properties of the modified epoxy matrix and its fiber reinforced composites were investigated systematically. The polymeric matrix possessed many good properties, including high strength, high elongation at break, low viscosity, long pot life at room temperature, and good water resistance. The special attentions are given to the matrix due to its low out gassing, low water absorption and radiation resistance. In addition, the fiber-reinforced composites showed a high strength conversion ratio of the fiber and good fatigue resistance. The dynamic and static of the composite material were studied by thermo gravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) with EDX. The influences of processing technique such as curing and proper mixing on the mechanical and interfacial properties were determined. The results demonstrated that the modified epoxy resin matrix is very suitable for applications in products fabricated with fiber-reinforced composites.


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