Interfacial Shear Strength of Polylactic Acid-Kenaf Fibre Biocomposites

2011 ◽  
Vol 471-472 ◽  
pp. 781-785 ◽  
Author(s):  
Hazleen Anuar ◽  
Ahmad Zuraida ◽  
Bálint Morlin ◽  
József Gábor Kovács

This paper reported the interfacial shear strength (IFSS) between kenaf fibre (KF) and polylactic acid (PLA) matrix which was measured using microbond tests device. The value of IFSS obtained in PLA-KF is comparable to other polymer with natural fibre reinforcements. The properties of single kenaf fibre was determined from tensile tests and also described in this paper. From single kenaf fibre properties, various mechanical properties can be estimated for various applications.

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yang Zou ◽  
Jinlong Jiang ◽  
Zhixiang Zhou ◽  
Xifeng Wang ◽  
Jincen Guo

Prefabricated UHPC-steel composite structure can make full use of the two materials’ mechanical and construction performance characteristics, with super mechanical properties and durability, which has been proved to be a very promising structure. However, using traditional mechanical connectors to connect prefabricated UHPC and steel not only is inconvenient for the prefabrication of UHPC components but also introduces heavy welding work, which is detrimental to the construction speed and antifatigue performance of the composite structure. Bonding UHPC-steel interface with epoxy adhesive is a potential alternative to avoid the above problem. In order to explore the mechanical properties of the prefabricated UHPC-steel epoxy bonding interface, this study carried out the direct shear test, tensile test, and tensile-shear test of the UHPC-steel epoxy-bonded interface (prefabricated UHPC-steel epoxy bonding interface). The results show that the interface failure is mainly manifested as the peeling of the epoxy-UHPC interface and the destruction of part of the UHPC matrix (the failure of the UHPC's surface). In pure shear and pure tension state, the interfacial shear strength is 5.14 MPa and the interfacial tensile strength is 1.18 MPa. In the tensile-shear state, the interfacial shear strength is 0.61 MPa and the interfacial tensile strength is 1.06 MPa. The stress-displacement curves of the interface normal and tangential direction are all in the shape of a two-fold line. The ultimate displacement was within 0.1 mm, showing the characteristics of brittle failure. Finally, a numerical model of the tensile specimen is established based on the cohesive interface element, and the interfacial tensile-shear coupling failure mechanism (tensile-shear coupling effect) is analyzed.


2020 ◽  
Vol 12 (01) ◽  
pp. 38-43
Author(s):  
Hisham M Hasan ◽  
◽  
Ahmed R Majeed ◽  

An experimental investigation using drag-out tensile test to calculate the interfacial shear strength for different embedded lengths of Kevlar and carbon fibers reinforced epoxy matrix with nanoclay (kaolinite) for different ratio weight, the interfacial shear strength increased by with increasing of embedded length and ratio weight fraction of nanoclay that adding to epoxy matrix.


2019 ◽  
Vol 827 ◽  
pp. 488-492
Author(s):  
Kazuto Tanaka ◽  
Daiki Kugimoto ◽  
Tsutao Katayama

Transportation sector is required to reduce CO2 emissions as environmental problems are becoming more serious. Carbon fibre reinforced thermoplastic (CFRTP) are expected to be applied to the structural parts of automobiles and aircrafts because of their superior mechanical properties such as high specific strength, high specific stiffness and high recyclability. One of the problems in using CFRTP for the structural parts is heat resistance, and it is necessary to clarify the mechanical properties under their service environmental temperature. The tensile strength of CFRTP at high temperatures decreases with temperature rise. The fibre matrix interfacial shear strength is reported to be improved by grafting of carbon nanotubes (CNTs) on the surface of carbon fibre. In this study, in order to clarify the effects of temperature on the fibre matrix interfacial shear strength of CNTs grafted carbon fibre reinforced PPS resin, single fibre pull-out test was conducted. While the interfacial shear strength of CNT grafted-CF/PPS is higher than that of As-received-CF/PPS at 25 °C, no significant difference was found in the interfacial shear strength of As-received-CF/PPS and CNT grafted-CF/PPS at 80 °C.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1374
Author(s):  
Xuchao Wang ◽  
Jun Zhao ◽  
Enzhao Cui ◽  
Xianhua Tian ◽  
Zhefei Sun

The interfacial structures and interfacial bonding characteristics between graphene and matrix in graphene-reinforced Al2O3–WC matrix ceramic composite prepared by two-step hot pressing sintering were systematically investigated. Three interfacial structures including graphene–Al2O3, graphene–Al2OC and graphene-WC were determined in the Al2O3–WC–TiC–graphene composite by TEM. The interfacial adhesion energy and interfacial shear strength were calculated by first principles, and it has been found that the interfacial adhesion energy and interfacial shear strength of the graphene–Al2OC interface (0.287 eV/nm2, 59.32 MPa) were far lower than those of graphene–Al2O3 (0.967 eV/nm2, 395.77 MPa) and graphene–WC (0.781 eV/nm2, 229.84 MPa) interfaces. Thus, the composite with the strong and weak hybrid interfaces was successfully obtained, which was further confirmed by the microstructural analysis. This interfacial structure could induce strengthening mechanisms such as load transfer, grain refinement, etc., and toughening mechanisms such as crack bridging, graphene pull-out, etc., which effectively improved mechanical properties.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 58 ◽  
Author(s):  
José H. Mina ◽  
Alex Valadez González ◽  
Mario F. Muñoz-Vélez

Biocomposites were prepared from a ternary matrix of polylactic acid (PLA), polycaprolactone (PCL), and thermoplastic starch (TPS) and reinforced with native fique fibers from southwestern Colombia. The influence of surface modification by alkalization of fique fibers on the interfacial properties of the biocomposite was studied using pull-out tests. Additionally, the effect of short fique fibers in three proportions (10%, 20%, and 30% (w/w)) on the tensile mechanical properties of the composite was evaluated. The experimental results indicated that the interfacial shear strength (IFSS) of the ternary matrix was predominantly influenced by PCL and characterized by the development of a weak interface that failed due to matrix yielding. Furthermore, the incorporation of short fique fibers increased the elastic modulus of the composite to values similar to those estimated with the Tsai–Pagano model. The alkalization treatment of the fique fibers improved the interface with the composite matrix, and this phenomenon was evidenced by the results of the micromechanical and tensile characterizations of the composite.


2019 ◽  
Vol 3 (1) ◽  
pp. 4 ◽  
Author(s):  
Kazuto Tanaka ◽  
Saya Okuda ◽  
Yoshitaka Hinoue ◽  
Tsutao Katayama

Carbon fiber reinforced thermoplastics (CFRTPs) are expected to be used for the structural parts of automobiles and aircraft due to their mechanical properties, such as high specific stiffness, high specific strength, short molding times and high recyclability. The fiber/matrix interface of the composite plays an important role in transmitting stress from the matrix to the reinforcing fibers. It was reported that grafting of carbon nanotubes (CNTs) on the carbon fiber can improve the fiber/matrix interfacial property. We have reported that CNTs, which are directly grafted onto carbon fiber using Ni as the catalyst by the chemical vapor deposition (CVD) method, can improve the fiber/matrix interfacial shear strength (IFSS) of carbon fiber/polyamide 6 (PA6). For practical use of CFRTPs, it is important to clarify the effects of water absorption on the mechanical properties of the composite material. In this study, the effects of water absorption on the fiber–matrix interfacial shear strength (IFSS) of carbon fiber reinforced polyamide resin and CNT-grafted carbon fiber reinforced polyamide resin were clarified by the single fiber pull-out test for specimens preserved in air, then in water for 24 h and re-dried after water absorption. The IFSS of carbon fiber/PA6 was significantly decreased by water absorption. In contrast, CNT-grafted carbon fiber/PA6 showed smaller degradation of the IFSS by water absorption.


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