scholarly journals Assessing the Flexural Properties of Epoxy Composites with Extremely Low Addition of Cellulose Nanofiber Content

2020 ◽  
Vol 10 (3) ◽  
pp. 1159 ◽  
Author(s):  
Yingmei Xie ◽  
Hiroki Kurita ◽  
Ryugo Ishigami ◽  
Fumio Narita
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Flexural Modulus ◽  
Strengthening Mechanism ◽  
Short Fiber ◽  
Cellulose Nanofiber ◽  
Resin Matrix ◽  
Element Analysis ◽  
Epoxy Resin Matrix ◽  
The Matrix

Epoxy resins are a widely used common polymer due to their excellent mechanical properties. On the other hand, cellulose nanofiber (CNF) is one of the new generation of fibers, and recent test results show that CNF reinforced polymers have high mechanical properties. It has also been reported that an extremely low CNF addition increases the mechanical properties of the matrix resin. In this study, we prepared extremely-low CNF (~1 wt.%) reinforced epoxy resin matrix (epoxy-CNF) composites, and tried to understand the strengthening mechanism of the epoxy-CNF composite through the three-point flexural test, finite element analysis (FEA), and discussion based on organic chemistry. The flexural modulus and strength were significantly increased by the extremely low CNF addition (less than 0.2 wt.%), although the theories for short-fiber-reinforced composites cannot explain the strengthening mechanism of the epoxy-CNF composite. Hence, we propose the possibility that CNF behaves as an auxiliary agent to enhance the structure of the epoxy molecule, and not as a reinforcing fiber in the epoxy resin matrix.

Investigation of Fiber-Reinforced Modified Epoxy Resin Composites

2012 ◽  
Vol 510-511 ◽  
pp. 577-584 ◽  
Author(s):  
A. Quddos ◽  
Mohammad Bilal Khan ◽  
R.N. Khan ◽  
M.K.K. Ghauri
Keyword(s):  
Epoxy Resin ◽  
High Strength ◽  
Polymeric Matrix ◽  
Fiber Reinforced Composites ◽  
Resin Matrix ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Epoxy Resin Matrix ◽  
The Matrix ◽  
Modified Epoxy

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.

Reinforced interface and mechanical properties of high strength carbon fiber composites

2020 ◽  
pp. 095400832095739
Author(s):  
Zibao Jiao ◽  
Zhengjun Yao ◽  
Jintang Zhou ◽  
Pengshu Yi ◽  
Chuanjun Lu
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Resin Matrix ◽  
Carbon Fiber Composites ◽  
Epoxy Resin Matrix ◽  
Winding Tension

Based on the surface analysis of carbon fiber, an epoxy resin matrix with good wettability to carbon fibers had been developed and studied, and the influence of winding tension on the interface and mechanical properties of the composite were studied. The surface morphology of carbon fiber and the active functional groups of sizing agent were analyzed. In order to form a good interface combination, the wettability between carbon fibers and epoxy resin matrix was characterized by dynamic contact angle. The winding tension played an important role in the mechanical properties of composites. Therefore, a kind of carbon fiber reinforced composites, Naval Ordnance Laboratory (NOL) rings were fabricated using different winding tensions. Particularly, when the winding tension was 30 N, the interfacial bonding between carbon fibers and resin matrix was the most compact and firm. The tensile strength and interlaminar shear strength (ILSS) of NOL rings reached high values, 2712 MPa and 75 MPa, respectively.

scholarly journals Numerical Investigations of Stress Concentration in Reinforcement Steel Structure by Composite Overlays

2019 ◽  
Vol 26 (4) ◽  
pp. 249-256
Author(s):  
Bogdan Szybiński ◽  
Mateusz Wygoda
Keyword(s):  
Stress Concentration ◽  
Epoxy Resin ◽  
Steel Structure ◽  
Resin Matrix ◽  
Fibre Reinforcement ◽  
Element Analysis ◽  
Premature Failure ◽  
Epoxy Resin Matrix ◽  
Stress Concentration Factors ◽  
Made In

AbstractThe stress concentration observed in the vicinity of cut-outs and holes in structural elements significantly influences the fatigue endurance of machines subjected to cyclic loads. Numerous studies have been made so far to improve this situation and increase the structure lifetime. Several design recommendations have also been worked out to avoid the problem of premature failure. The proposed article illustrates the influence of the composite overlays applied around the cut-outs made in flat steel constructional elements subjected to axial tension. The detailed study concerns the reinforcement made from the FRP (fibre reinforcement polymer) composite applied around the notches. Two types of composite materials were used, namely: TVR 380 M12/R-glass (glass fibres embedded in epoxy resin matrix) and AS4D/9310 (carbon fibres embedded in epoxy resin matrix). In the first step, the detailed numerical studies (finite element analysis) were performed for the steel samples (with no overlays added) with cut-outs made in the form of circle, square and triangle hole (the last two with rounded corners). The results of these studies were compared with the existing analytical solutions with respect to the stress concentration factors (SCF) estimation. The relatively good conformity was observed when using dense meshes of finite elements placed around the void vicinity. In the next step, the composite overlays were applied around cut-outs and their influence on the stress concentration was investigated. The influence of the fibre orientation, numbers of layers, sizes of the composite overlay used were considered. It was proved that the application of composite overlays evidently decreases the stress concentration around the notches.

scholarly journals Polymer Composite Materials Fiber-Reinforced for the Reinforcement/Repair of Concrete Structures

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2058 ◽  
Author(s):  
George Soupionis ◽  
Pantelitsa Georgiou ◽  
Loukas Zoumpoulakis
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Compression Strength ◽  
Artificial Aging ◽  
Bending Strength ◽  
Resin Matrix ◽  
Epoxy Resin Matrix

The present paper deals with the use of polymeric matrix composite materials reinforced with carbon fiber as concrete shear reinforcement materials. Accordingly, cement specimens were manufactured and coated with various types of carbon fabrics and epoxy resin in liquid and solid form (paste). Additionally, composite materials of epoxy resin matrix reinforced with carbon fiber fabrics were manufactured. In all the specimens, the mechanical properties were estimated; the cement samples coated with composite materials of epoxy resin matrix reinforced with carbon fiber fabrics were tested for compressive strength, while the other specimens were tested for shear and bending strength. The specimens were subjected to artificial aging through heat treatment for 8, 12 and 16 days. During the process of artificial aging, the temperature in the chamber reached the range of 65–75 °C. These composite materials exhibited high mechanical properties combined with adaptability. Both an external deterioration of the materials as well as a reduction in mechanical properties during their artificial aging heat treatment were observed. This was shown in the specimens that were not subjected to artificial aging, with an applied compression strength of 74 MPa, and after the artificial aging, there was a decrease of ~7%, with the compression strength being reduced to 68 MPa.

Mechanical properties of mechanically-defibrated cellulose nanofiber reinforced epoxy resin matrix composites

2020 ◽  
pp. 002199832096743
Author(s):  
Hiroki Kurita ◽  
Ryugo Ishigami ◽  
Chen Wu ◽  
Fumio Narita
Keyword(s):  
Epoxy Resin ◽  
Volume Fraction ◽  
Dispersion Model ◽  
Low Cost ◽  
Flexural Modulus ◽  
Cellulose Nanofibers ◽  
General Purpose ◽  
Resin Matrix ◽  
Mechanical Mixing ◽  
Epoxy Resin Matrix

Cellulose nanofibers (CNF) have recently attracted attention as one of the reinforcements for composite materials. However, the same as other nanofibers, CNFs can be easily agglomerated and the nano-level defibration is necessary to obtain their outstanding properties in polymer matrices. To overcome this issue, two major defibration methods, chemical and mechanical defibration have been considered. The chemically-defibrated CNF is expensive and so prevents the practical realization of CNF as general-purpose products. Therefore, the mechanical defibration method by a clean low-cost water jet was focused on. Mechanically-defibrated CNF reinforced epoxy resin matrix (Epoxy-CNF) composites was fabricated via mechanical mixing and evaluated the variation of their tensile and flexural properties with different CNF volume fractions. The tensile and flexural modulus of the epoxy composites were increased by CNF addition, while the fracture elongation was decreased. The calculated ultimate tensile strength (UTS) and ultimate flexural strength (UFS), using the aspect ratio of the agglomerated CNF clusters, indicated the validity of the random dispersion model considering the agglomerated CNF as one whole fiber. It seems that epoxy resin is enhanced by the mechanical interaction when the CNF volume fraction is higher than 0.37 vol.%.

Tribological and mechanical properties of self-lubrication epoxy composites filled with activated carbon particles containing lubricating oil

RSC Advances ◽  
2016 ◽  
Vol 6 (58) ◽  
pp. 52596-52603 ◽  
Author(s):  
Meiling Li ◽  
Huaiyuan Wang ◽  
Dujuan Liu ◽  
Rui Wang ◽  
Yanji Zhu
Keyword(s):  
Mechanical Properties ◽  
Activated Carbon ◽  
Epoxy Resin ◽  
Epoxy Composites ◽  
Lubricating Oil ◽  
Resin Matrix ◽  
Epoxy Resin Matrix ◽  
Carbon Particles ◽  
Activated Carbon Particles

A self-lubrication composite incorporating activated carbon particles containing lubricating oil (AC-oil) was fabricated in an epoxy resin matrix.

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