scholarly journals STUDY ON THE UV-CROSSLINKING PROCESS OF THE DIANE-EPOXY RESIN/POLY(TETRAHYDROFURANE) DIVINYL ETHER SYSTEM II. INFLUENCE OF THE CONTENT OF EPOXY RESIN AND POLY(TETRAHYDROFURANE) DIVINYL ETHER ON THE PHOTOCROSSLINKING OF THE DIANE EPOXY/POLY (TETRAHYDROFURA

2016 ◽  
Vol 54 (2) ◽  
pp. 249
Author(s):  
Dao Phi Hung ◽  
Nguyen Anh Hiep ◽  
Mac Van Phuc
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Impact Resistance ◽  
Divinyl Ether ◽  
Crosslinking Reaction ◽  
Mass Ratio ◽  
Uv Crosslinking ◽  
Crosslinking Process ◽  
Relative Hardness ◽  
Ether System

The effect of diane-epoxy resin (DE) and poly(tetrahydrofuran) divinyl ether (DVE) content on the photo crosslinking reaction of the DE/DVE system with triarylsulfonium salt (TAS) as photo-initiator were investigated. The results showed that increasing DVE content improved some of physico-mechanical properties of photocrosslinked coatings although the relative hardness and the speed of photocrosslinking reaction reduced. The results of the changes of functional groups, relative hardness and gel fraction as well as the physico-mechanical properties of UV-cured coatings based on DE/DVE/TAS system illustrated that suitable mass ratio of constituents was 80/20/5. The UV-cured coating based on the system DE/DVE/TAS = 80/20/5 cross-linked completely after 3.6 seconds UV-exposure and having good physico-mechanical properties: impact resistance reached 180 kg.cm; the flexibility obtained 1mm; the adhesion and relative hardness were point 1 and 0.7, respectively.

scholarly journals STUDY OF THE INFLUENCE OF CONSTITUENT RATIO ON THE CROSSLINKING REACTION OF CASTOR OIL MODIFIED EPOXY RESIN BY 4.4’-DIAMINO DIPHENYLMETHANE

2016 ◽  
Vol 54 (4) ◽  
pp. 501
Author(s):  
Do Minh Thanh ◽  
Le Xuan Hien ◽  
Nguyen Tien Dung
Keyword(s):  
Epoxy Resin ◽  
Castor Oil ◽  
Impact Resistance ◽  
Crosslinking Reaction ◽  
Curing Time ◽  
Optimal Conditions ◽  
Swelling Degree ◽  
Gel Fraction ◽  
Relative Hardness ◽  
Modified Epoxy

The influence of the contents of epoxy resin modified by castor oil (ECO), 4,4’- diamino diphenyl methan (DDM) on the crosslinking reaction of ECO by DDM at 1800C have been studied and the mol ratio of A/E = 1, curing time of 270 min have been determined to be optimal conditions for formation of the cured coating having gel fraction, swelling degree, flexibility, adhesion, impact resistance, and relative hardness of 86%; 188 %; 1 mm, 0 point, 200 kG.cm and 0.33, respectively.

Preparation and Characterization of Sawdust Derived Bio-Fuel Pellets Depending on "Solid Bridge" Intertwining Action of Hyacinth Fiber

2014 ◽  
Vol 878 ◽  
pp. 450-458
Author(s):  
Ling Jun Kong ◽  
Xiong Fei Zhang ◽  
Shuang Hong Tian ◽  
Ting Liu ◽  
Ya Xiong
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Elastic Recovery ◽  
Impact Resistance ◽  
Resistance Index ◽  
Cost Effective ◽  
Environmental Benefits ◽  
Fuel Pellet ◽  
Mass Ratio ◽  
Solid Bridge

Densified biomass pellets named as H/S-BPs were prepared from waste wood sawdust (S) in the presence of water hyacinth fiber (H) as solid bridge under room temperature and 6 MPa lower than in the previous study. Mechanical properties including relaxed density (ρr), resiliency (R), abrasion resistance (AR) and impact resistance index (IRI) were evaluated. Results showed that adding H greatly reduced negative effect of resiliency on the mechanical properties of H/S-BPs during storage. For example, H/S-BPs compressed at 6 MPa in an H/S mass ratio of 1 to 3 presented lower resiliency of 10% and higher relaxed density of 1.04 kg dm-3 than pellets without H fiber. This is due to the intertwining action of H fiber, what fabricates solid bridge, replacing the bonding creating by applying high pressure to resist the disruptive force caused by elastic recovery. Thus, compression of waste H and S in a mass ratio of 1 to 3 at room temperature under 6 MPa is a cost-effective process to produce densified sustainable bio-fuel pellet as well as dispose waste S and H, combining the economical and environmental benefits.

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.

INFLUENCE OF TEMPERATURE-DEPENDENT RESIN BEHAVIOR ON NUMERICAL PREDICTION OF EFFECTIVE CTES OF 3D WOVEN COMPOSITES

2021 ◽  
Author(s):  
KOSTIANTYN VASYLEVSKYI ◽  
BORYS DRACH ◽  
IGOR TSUKROV
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Elevated Temperatures ◽  
Impact Resistance ◽  
Woven Composites ◽  
Nonlinear Dependence ◽  
Thermal And Mechanical Properties ◽  
Effective Coefficients ◽  
3D Woven Composites

3D woven composites are well known for their high strength, dimensional stability, delamination, and impact resistance. They are often used in aerospace, energy, and automotive industries where material parts can experience harsh service conditions including substantial variations in temperature. This may lead to significant thermal deformations and thermally-induced stresses in the material. Additionally, 3D woven composites are often produced using resin transfer molding (RTM) technique which involves curing the epoxy resin at elevated temperatures leading to accumulation of the processing-induced residual stress. Thus, understanding of effective thermal behavior of 3D woven composites is essential for their successful design and service. In this paper, the effective thermal properties of 3D woven carbon-epoxy composite materials are estimated using mesoscale finite element models previously developed for evaluation of the manufacturing-induced residual stresses. We determine effective coefficients of thermal expansion (CTEs) of the composites in terms of the known thermal and mechanical properties of epoxy resin and carbon fibers. We investigate how temperature sensitivity of the thermal and mechanical properties of the epoxy influences the overall thermal properties of the composite. The simulations are performed for different composite reinforcement morphologies including ply-to-ply and orthogonal. It is shown that even linear dependence of epoxy’s stiffness and CTE on temperature results in a nonlinear dependence on temperature of the overall composite’s CTE.

scholarly journals The Effect of Multilevel Carbon Reinforcements on the Fire Performance, Conductivity, and Mechanical Properties of Epoxy Composites

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 303 ◽  
Author(s):  
Andrea Toldy ◽  
Gábor Szebényi ◽  
Kolos Molnár ◽  
Levente Tóth ◽  
Balázs Magyar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Impact Resistance ◽  
Fire Performance ◽  
Multiwalled Carbon ◽  
Peak Heat Release Rate ◽  
Flame Retarded ◽  
The Impact

We studied the effect of a multilevel presence of carbon-based reinforcements—a combination of conventional load-bearing unidirectional carbon fiber (CF) with multiwalled carbon nanotubes (CNT) and conductive CNT-containing nonwoven carbon nanofabric (CNF(CNT))—on the fire performance, thermal conductivity, and mechanical properties of reference and flame-retarded epoxy resin (EP) composites. The inclusion of carbon fibers and flame retardant reduced the peak heat release rate (pHRR) of the epoxy resins. The extent to which the nanoreinforcements reduced the pHRR depended on their influence on thermal conductivity. Specifically, high thermal conductivity is advantageous at the early stages of degradation, but after ignition it may lead to more intensive degradation and a higher pHRR; especially in the reference samples without flame retardant. The lowest pHRR (130 kW/m2) and self-extinguishing V-0 UL-94 rating was achieved in the flame-retarded composite containing all three levels of carbon reinforcement (EP + CNF(CNT) + CNT + CF FR). The plasticizing effect of the liquid flame retardant impaired both the tensile and flexural properties; however, it significantly enhanced the impact resistance of the epoxy resin and its composites.

Synthesis of Two Novolac Type Epoxy Resin Curing Agents and their Application

2013 ◽  
Vol 634-638 ◽  
pp. 3008-3016
Author(s):  
Yan Li ◽  
Zhi Nan Zhou ◽  
Xiao Yan Xu ◽  
Long Xie
Keyword(s):  
Mechanical Properties ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Curing Kinetics ◽  
Mass Ratio ◽  
Scanning Calorimetry ◽  
Curing Reaction ◽  
Novolac Resins ◽  
Curing Agents ◽  
Resin Curing

Two Novolac Resins Were Synthesized by the Reaction between Bisphenol A and Benzaldehyde (bis-BENR) or Bisphenol A and P-hydroxybenzaldehyde (bis-PHNR). Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) Were Applied to Characterize the Molecular Structure of Bis-BENR (or Bis-PHNR). then the Two Novolac Resins Were Used as Curing Agent for Bisphenol A Type Epoxy Resin (DGEBA). the Curing Reaction and Curing Kinetics Were Studied by Dynamic FTIR and Differential Scanning Calorimetry (DSC). Dynamic FTIR Showed that the Two Novolac Resins Reacted with Epoxy Resins and Formed a Crosslinking Network Structure. DSC Results Show that the Optimum Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, under which the Curing Reaction Processed Completely. the Mechanical Properties and Sulfide Resistance of DGEBA/bis-BENR (or Bis-PHNR) System Were Also Investigated. the Results Showed that when the Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, the Curing Coatings Had Optimum Mechanical Properties and Sulfide Resistance.

scholarly journals Mechanical and Flame-Retardant Properties of Nanocomposite Based on Epoxy Resin Combined with Epoxidized Linseed Oil, Which Has the Presence of Nanoclay and MWCNTs

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Tuan Anh Nguyen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Fire Resistance ◽  
Flame Retardants ◽  
Linseed Oil ◽  
Impact Resistance ◽  
Limiting Oxygen Index

One of the main disadvantages of epoxy resins is brittleness and flammability, which is one of the biggest threats and the reason for limiting advanced applications. In this study, Epikote 240 (EP) epoxy resin was plasticized with epoxidized flaxseed oil (ELO) at different concentrations (EP/ELO ratios 95/5; 90/10; 85/15; 80/20; 75/25). Then, nanoclay additives and MWCNTs are simultaneously dispersed into the EP/ELO blend by using ultrasonic vibration. The dispersion of ELO and nanoclay additives (nanoclay and MWCNTs) in epoxy resin is observed by using the scanning electron microscope in combination with the XRD method. The effect of ELO, nanoadditives on mechanical properties, and flame retardants is assessed by tensile strength, flexural strength, compressive strength, impact resistance, UL 94HB method, and limiting oxygen index. Experimental results have shown that the mixing ratio of 90/10 w/w is the ratio for good compatibility, high mechanical properties, and fire retardation compared with other ratios. When adding MWCNTs as well as nanoclay I.30E to Epikote 240 epoxy, the mechanical strength and fire resistance have changed greatly: tensile strength of 85.45 MPa, flexural strength of 116.32 MPa, compressive strength of 189.25 MPa, impact resistance Izod of 24.37 kJ/m2, and fire resistance reached at V1.

scholarly journals Study on Fire Resistance Ability and Mechanical Properties of Composites Based on Epikote 240 Epoxy Resin and Thermoelectric Fly Ash: An Ecofriendly Additive

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Tuan Anh Nguyen ◽  
Quang Tung Nguyen ◽  
Xuan Canh Nguyen ◽  
Van Hoan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
Impact Resistance ◽  
Test Method ◽  
Chemical Treatments ◽  
Synthetic Materials ◽  
Resistance Decrease

In this study, fly ash was tested as a filler in epoxy with concentrations of 5, 10, and 20 wt.%. Fly ash particles were modified by chemical treatments (using NaOH and HCl) to enhance the compatibility and adhesion, making mechanical properties and flame retardancy of materials better. Flexural strength, tensile strength, and impact resistance decrease as fly ash content increases. The compressive strength is further increased by the addition of fly ash (compressive strength of the materials including 5, 10, 20 wt.% of fly ash modified with NaOH is 176.01, 189.90, and 197.07 MPa, respectively). The interface between fly ash and epoxy matrix plays an important role in determining the mechanical strength and flame retardancy of synthetic materials. The results of UL-94HB and LOI test method for composite materials including 20 wt.% fly ash (modified by NaOH) reached 13.45 mm/min and 22.4%, respectively. These results showed that fly ash is an efficient additive as a flame retardant which decreases the amounts of additives in products and improves their efficiency. Fly ash was also dispersed into epoxy resin to enhance its resistance to oxidation.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

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