scholarly journals Surface Modification of Bamboo Fibers to Enhance the Interfacial Adhesion of Epoxy Resin-Based Composites Prepared by Resin Transfer Molding

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2107 ◽  
Author(s):  
Dong Wang ◽  
Tian Bai ◽  
Wanli Cheng ◽  
Can Xu ◽  
Ge Wang ◽  
...  
Keyword(s):  
Surface Modification ◽  
Epoxy Resin ◽  
Condensation Reaction ◽  
Resin Transfer Molding ◽  
Coupling Agents ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Transfer Molding ◽  
Bamboo Fibers ◽  
The Impact

Bamboo fibers (BFs)-reinforced epoxy resin (EP) composites are prepared by resin transfer molding (RTM). The influence of BFs surface modification (NaOH solution or coupling agents, i.e., KH550 and KH560) on interfacial properties of BFs/EP composites is systematically investigated. The synergistic effect of hydrolysis, peeling reaction of BFs, and the condensation reaction of hydrolyzed coupling agents are confirmed by FTIR. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveal that the interfacial compatibility of NaOH- and silane-modified BFs/EP composites was significantly improved. KH550-modified BFs/EP composite renders optimal tensile, flexural, and impact strength values of 68 MPa, 86 MPa, and 226 J/m. The impact resistance mechanism at the interface of BFs/EP composites was proposed. Moreover, the dynamic mechanical properties, creep behavior, and differential scanning calorimetry of BFs/EP composites have also been carried out to understand thermal stabilities. Overall, the surface-modified BFs-reinforced EP composites exhibited superior interfacial bonding.

scholarly journals Impact and shear properties of carbon fabric/ poly-dicyclopentadiene composites manufactured by vacuum‐assisted resin transfer molding

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 437-443 ◽  
Author(s):  
Hyeong Min Yoo ◽  
Moo Sun Kim ◽  
Bum Soo Kim ◽  
Dong Jun Kwon ◽  
Sung Woong Choi
Keyword(s):  
Impact Strength ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Resin Transfer Molding ◽  
Maximum Shear Stress ◽  
Weight Percent ◽  
Fiber Volume ◽  
Shear Properties ◽  
Transfer Molding ◽  
The Impact

AbstractDicyclopentadiene (DCPD) resin has gained popularity owing to its fast curing time and ease of processing with a low viscosity in the monomer state. In the present study, the impact and shear properties of a carbon fiber (CF)/p-DCPD composite were investigated. The CF/p-DCPD composite was manufactured by vacuum-assisted resin transfer molding with CF as the reinforcement and p-DCPD as the resin with a maximum fiber volume fraction of 55 weight percent. Impact and shear properties of the CF/p-DCPD composite were evaluated and compared with those of a CF/Epoxy composite. The maximum shear stress and modulus of the CF/p-DCPD composite were lower than that of the CF/Epoxy composite. However, the CF/p-DCPD composite had higher toughness than that of the CF/Epoxy composite; this indicates that it is tougher and exhibits a more ductile load-displacement response with a lower modulus and larger failure deformation. The impact strength of the CF/p-DCPD composite was about three time that of the CF/Epoxy composite. The higher impact strength of the CF/p-DCPD composite is attributed to the resin characteristics: epoxy resin has a more brittle behavior, and hence, higher energy is required for crack propagation due to fracture.

scholarly journals Curing Kinetics, Mechanical Properties and Thermomechanical Analysis of Carbon Fiber/epoxy Resin Laminates with Different Ply Orientations

2021 ◽  
Author(s):  
Chenglin Zhang ◽  
Guohua Gu ◽  
Shuhua Dong ◽  
Zhitao Lin ◽  
Chuncheng Wei ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Impact Strength ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
Bending Strength ◽  
Fiber Composite ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
The Impact ◽  
Carbon Fiber Epoxy

Abstract In this study, the nonisothermal differential scanning calorimetry (DSC) was carried out to evaluate the curing reaction of fiber/epoxy laminates. The optimal curing process of the prepreg was obtained by T-β extrapolation method and nth-order reaction curing kinetic equation. The bending strength, impact strength and thermodynamic properties of the composite laminates with different ply orientations were investigated, respectively. The results show that the apparent activation energy and the reaction order of the prepregs are 82.89 kJ/mol and 0.92, respectively. The curing process of carbon fiber/epoxy resin prepreg is 130 ℃ /60min + 160 ℃/30 min. The bending strength of [0]10 laminate is 1948.3 MPa, which is 11.8 times higher than that of [+ 45/-45]5s laminate, and 96.4% higher than that of [0/90]5s laminate. The impact strength of [0]10 laminate is higher than that of [+ 45/-45]5s and [0/90]5s laminates. The glass transition temperature (Tg) of the laminates is 142 ~ 146 ℃, and the loss factor of [0]10 laminate is significantly higher than that of [+ 45/-45]5s and [0/90]5s laminates. This research provides a theoretical basis for the further application of prepregs to fiber composite materials.

Studies of the Physical Properties of Cycloaliphatic Epoxy Resin Reacted with Anhydride Curing Agents

2017 ◽  
Vol 737 ◽  
pp. 248-255 ◽  
Author(s):  
Tae Hee Kim ◽  
Dae Yeon Kim ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Physical Properties ◽  
Reaction Kinetics ◽  
Epoxy Resin ◽  
High Performance ◽  
Industrial Applications ◽  
Scanning Calorimetry ◽  
Low Viscosity ◽  
High Performance Polymer ◽  
Curing Agents ◽  
The Impact

The preparation of high performance epoxy composites for industrial applications has been extensively researched. In this report, we study the change in physical properties and reaction kinetics between epoxy resin and curing agents of similar geometry. For the experiments, celloxide 2021P, an epoxy resin having low viscosity, was blended with three different curing agents: methylhexahydropthalic acid, methyltetrahydropthalic acid, and 5-norbornene-2, 3-dicarboxylic anhydride. The amount of 1, 2-dimethylimidazole catalyst was controlled, and the highest heat flow temperature (Tpeak) was observed at around 145 °C. The impact on reaction kinetics relative to the change in heating rate was studied with differential scanning calorimetry (DSC) for each of the curing agents. The glass transition temperature (Tg) of each composition was measured with a second DSC cycle. The prepared epoxy compositions were thermally cured in a metallic mold to provide pure epoxy resins without fillers. Finally, the flexural strengths of these resins were compared to each other. The authors believe that insights into choosing an appropriate epoxy binder are useful when it comes to the overall preparation of high performance polymer composites.

Toughness and Thermal Properties of a Dimer Acid Modified Tetrafunctional Epoxy Resin

2015 ◽  
Vol 764-765 ◽  
pp. 107-110 ◽  
Author(s):  
Ming Ming Yu ◽  
Bin Feng ◽  
Min Yang ◽  
Li Qi Liu ◽  
Hong Li ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Epoxy Resin ◽  
Thermo Gravimetric Analysis ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Impact Testing ◽  
Gravimetric Analysis ◽  
Thermal Stabilities ◽  
The Impact ◽  
Tetrafunctional Epoxy

In order to improve the toughness of the cured aromatic tetrafunctional epoxy resins in the premise of influencing the thermal properties as little as possible, the aromatic tetrafunctional epoxy named N,N,N’,N’-tetraglycidyl-4,4’-diaminodiphenyl ether (TGDDE) was modified by a dimer carboxylic acid (DFA), and then the epoxies were cured with methyl nadic anhydride (MNA). In the present work, the toughness was characterized with the impact resistance tested by pendulum impact testing. Besides, the thermal properties of the cured epoxy resin were investigated with the thermo-gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The impact testing results indicated that the toughness of the cured resins could be improved after the modification and increased with the increasing content of DFA. The thermal analysis showed that the thermal properties of the cured resins were not influenced obviously since the thermal stabilities of the products could be improved and the glass transition temperature of them were not influenced obviously when the tetrafunctional epoxy modified with appropriate content of DFA.

scholarly journals Properties of epoxy-thiokol materials based on the products of the preliminary reaction of thioetherification

2021 ◽  
pp. 128-136
Author(s):  
K.M. Sukhyy ◽  
◽  
E.A. Belyanovskaya ◽  
A.N. Nosova ◽  
M.K. Sukhyy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Adhesive Strength ◽  
Impact Resistance ◽  
Maximum Level ◽  
Scanning Calorimetry ◽  
Mechanical Mixtures ◽  
The Impact ◽  
Fracture Work ◽  
Specific Impact

In order to improve the adhesive and physical-mechanical properties of epoxy-thiocol compositions cured without heat treatment, we propose to carry out the reaction of interaction between thiokol mercaptan groups and oxirane cycles of epoxy resin at an elevated temperature before introducing a curing agent, and then use the product of this thioetherification reaction for curing at room temperature. The temperature range of the thioetherification reaction (90–1800С) was determined by the method of differential scanning calorimetry. The optimal temperature (1600С) and duration of the preliminary thioetherification reaction (2 hours) were determined, which ensure the maximum level of adhesive strength and physical-mechanical properties. It was shown that composite materials based on the products of the thioetherification reaction significantly outperform analogs based on mechanical mixtures of epoxy resin and thiokol in terms of cohesive and adhesive strength, deformation capacity, fracture work and specific impact strength. The impact resistance and shear strength of adhesive joints are especially significantly increased during the curing of the compositions without external heat supply.

Effects of Graphene on a Resin Transfer Molding Process Using Bisphenol A Based Epoxy Resin

2010 ◽  
Vol 123-125 ◽  
pp. 535-538
Author(s):  
Huu Hieu Nguyen ◽  
Dae Woo Lee ◽  
Quang Trung Troung ◽  
Seong Woo Yun ◽  
Chi Hoon Choi ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Epoxy Resin ◽  
Polymer Composites ◽  
Epoxy Resins ◽  
Resin Transfer Molding ◽  
Analysis Tool ◽  
Molding Process ◽  
Liquid Resin ◽  
Transfer Molding ◽  
Computational Fluid Dynamics Analysis

Resin transfer molding is a popular process to fabricate polymer composites reinforced with a large amount of glass or carbon fibers. In general, fiber reinforcements are put in a mold, and a liquid resin such as epoxy resin is injected into the mold after preheating. For successful production of polymer composites via a resin transfer molding process, the filling and curing stages of the liquid resin as well as the mold design should be optimized. Recently, polymer composites reinforced with nanoparticles are attracting attention of researchers in academia and industries because efficient reinforcement can be achieved by small loading of nanoparticles such as carbon nanotubes and exfoliated clays. In this work, as an effort to develop light weight automotive parts, graphenes were investigated as a nano size reinforcement of epoxy resin for resin transfer molding. Graphenes were prepared from graphites by microwave irradiation. Addition of graphenes to bisphenol A based epoxy resins such as YD-128 from Kukdo Chemical results in an increase in viscosity and shear thinning behavior, affecting the filling process. The curing of epoxy resins is also affected by graphenes. In order to develop a model for simulation of the filling and curing of epoxy resins containing different amounts of graphenes in the resin transfer molding, FLUENT and MATLAB have been used in this study, which are a finite element based computational fluid dynamics analysis tool and a general purpose numerical analysis tool, respectively. The effects of graphenes on the mold filling pattern and curing profile are discussed for the resin transfer molding of bisphenol A based epoxy resins.

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