scholarly journals Effect of Nickel Doping on the Cure Kinetics of Epoxy/Fe3O4 Nanocomposites

2020 ◽  
Vol 4 (3) ◽  
pp. 102
Author(s):  
Maryam Jouyandeh ◽  
Zohre Karami ◽  
Seyed Mohammad Reza Paran ◽  
Amin Hamed Mashhadzadeh ◽  
Mohammad Reza Ganjali ◽  
...  
Keyword(s):  
Short Communication ◽  
Cure Kinetics ◽  
Partial Replacement ◽  
Crosslinking Reaction ◽  
Kinetics Analysis ◽  
Scanning Calorimetry ◽  
Nickel Doping ◽  
Cure Kinetic ◽  
Rate Of Reaction ◽  
Kinetics Of

This short communication aims to evaluate the cure kinetics of epoxy/NixFe3−xO4 nanocomposites. Differential scanning calorimetry (DSC) provided support for cure kinetics analysis based on the variation of activation energy (Eα) as a function of the extent of crosslinking reaction, α. The average values of Eα calculated based on Kissinger and Friedman methods were 59.22 and 57.35 kJ/mol for the neat epoxy, 43.37 and 48.74 kJ/mol for the epoxy/Fe3O4, and eventually 50.48 and 49.19 kJ/mol for the epoxy/NixFe3−xO4 nanocomposites. The partial replacement of Fe2+ ion sites in the Fe3O4 crystal lattice by the Ni2+ ions changed to some content the cure kinetic profile because of the fact that a lower level of energy was needed for curing by incorporation of NixFe3−xO4 into the epoxy matrix. The rate of reaction calculated theoretically adequately fitted with experimental profiles obtained in DSC experiments.

scholarly journals Dynamic Cure Kinetics and Physical-Mechanical Properties of PEG/Nanosilica/Epoxy Composites

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Haleh Nowruzi Varzeghani ◽  
Iraj Amiri Amraei ◽  
Seyed Rasoul Mousavi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cure Kinetics ◽  
Diglycidyl Ether ◽  
Solid Particles ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Cure Kinetic ◽  
Cure Temperature ◽  
Kinetics Of

This study investigated the effect of polyethylene glycol (PEG) and nanosilica (NS) on the physical-mechanical properties and cure kinetics of diglycidyl ether of bisphenol-A-based epoxy (DGEBA-based EP) resin. For this purpose, tensile and viscometry tests, dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC) were carried out under dynamic conditions. The results showed that adding NS and PEG enhances the maximum cure temperature as well as the heat of cure reaction (ΔH) in EP-NS, while it decreases in EP-PEG and EP-PEG-NS. The cure kinetic parameters of EP-PEG-NS were calculated by Kissinger, Ozawa, and KSA methods and compared with each other. The Ea calculated from the Kissinger method (96.82 kJ/mol) was found to be lower than that of the Ozawa method (98.69 kJ/mol). Also, according to the KAS method, the apparent Ea was approximately constant within the 10-90% conversion range. Tensile strength and modulus increased by adding NS, while tensile strength diminished slightly by adding PEG to EP-NS. The glass transition temperature (Tg) was calculated using DMTA which was increased and decreased by the addition of NS and PEG, respectively. The results of the viscometry test showed that the viscosity increased with the presence of both PEG and NS and it prevented the deposition of solid particles.

Phenomenological model for the reaction order n in the kinetics of curing an elastomer EPDM

MRS Advances ◽  
2019 ◽  
Vol 4 (59-60) ◽  
pp. 3299-3310
Author(s):  
S. Gómez-Jimenez. ◽  
A.M. Becerra-Ferreiro. ◽  
E. Jareño-Betancourt. ◽  
J. Vázquez-Penagos.
Keyword(s):  
Reaction Order ◽  
Cure Kinetics ◽  
Analytical Description ◽  
Crosslinking Reaction ◽  
Precise Control ◽  
Short Period ◽  
Rate Of Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Modelling And Optimization

AbstractThe precise control of curing reaction parameters allows a better crosslinking polymer. Modelling and optimization of this process require a correct kinetic of curing model. The kinetics of the crosslinking reaction is studied for the ethylene propylene diene monomer (EPDM) synthetic elastomer by mobile die rheometer (MDR). The kinetic parameters of reaction were calculated from Kamal-Ryan, Sestak-Berggren, and the Isayev-Deng methods at different temperatures. An Arrhenius-type function for the order of reaction n is introduced to improve the adjusting. Finally, a graphical and analytical description of the cure kinetics was developed. The order of reaction is predicted to better establishment of processing time. It was noted that for EPDM at higher temperatures, the increase of the rate of reaction occurs in short period of time, which could cause premature curing if the supply system is inadequate.

scholarly journals Nonisothermal Cure Kinetics of Epoxy/Polyvinylpyrrolidone Functionalized Superparamagnetic Nano-Fe3O4 Composites: Effect of Zn and Mn Doping

2020 ◽  
Vol 4 (2) ◽  
pp. 55 ◽  
Author(s):  
Maryam Jouyandeh ◽  
Mohammad Reza Ganjali ◽  
Farzad Seidi ◽  
Huining Xiao ◽  
Mohammad Reza Saeb
Keyword(s):  
Superparamagnetic Iron Oxide ◽  
Cure Kinetics ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Partial Replacement ◽  
Scanning Calorimetry ◽  
Nano Fe3o4 ◽  
Kinetics Of ◽  
Mn Doped ◽  
Good Agreement

The effects of the bulk and surface modification of nanoparticles on the cure kinetics of low-filled epoxy nanocomposites containing electrochemically synthesized polyvinylpyrrolidone (PVP) functionalized superparamagnetic iron oxide (PVP-SPIO), Zn-doped PVP-SPIO (Zn-PVP-SPIO), and Mn-doped PVP-SPIO (Mn-PVP-SPIO) were studied using differential scanning calorimetry (DSC) and cure kinetics analyses. Integral and differential isoconversional methods were used to calculate the activation energies (Eα) and consequently propose the appropriate reaction model for the curing reaction under nonisothermal conditions. According to the alteration of Eα versus the fractional extent of conversion, the Eα trend was changed through the partial replacement of Fe2+ sites by the Zn2+ and Mn2+ cations in the general formula of MxFe3-xO4, due to smaller amounts of energy being required for curing by the incorporation of Zn-PVP-SPIO and Mn-PVP-SPIO nanoparticles into the epoxy resin. A good agreement was observed between the theoretical calculation and the observed calorimetric data for the model validation.

Effects of additives on the cure kinetics of vinyl ester pultrusion resins

2021 ◽  
pp. 002199832110015
Author(s):  
Alexander Vedernikov ◽  
Yaroslav Nasonov ◽  
Roman Korotkov ◽  
Sergey Gusev ◽  
Iskander Akhatov ◽  
...  
Keyword(s):  
Vinyl Ester ◽  
Mean Squared Error ◽  
Cure Kinetics ◽  
Zinc Stearate ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Predicted Values ◽  
Kinetics Of ◽  
Final Degree

Pultrusion is a highly efficient composite manufacturing process. To accurately describe pultrusion, an appropriate model of resin cure kinetics is required. In this study, we investigated cure kinetics modeling of a vinyl ester pultrusion resin (Atlac 430) in the presence of aluminum hydroxide (Al(OH)3) and zinc stearate (Zn(C18H35O2)2) as processing additives. Herein, four different resin compositions were studied: neat resin composition, composition with Al(OH)3, composition comprising Zn(C18H35O2)2, and composition containing both Al(OH)3 and Zn(C18H35O2)2. To analyze each composition, we performed differential scanning calorimetry at the heating rates of 5, 7.5, and 10 K/min. To characterize the cure kinetics of Atlac 430, 16 kinetic models were tested, and their performances were compared. The model based on the [Formula: see text]th-order autocatalytic reaction demonstrated the best results, with a 4.5% mean squared error (MSE) between the experimental and predicted data. This study proposes a method to reduce the MSE resulting from the simultaneous melting of Zn(C18H35O2)2. We were able to reduce the MSE by approximately 34%. Numerical simulations conducted at different temperatures and pulling speeds demonstrated a significant influence of resin composition on the pultrusion of a flat laminate profile. Simulation results obtained for the 600 mm long die block at different die temperatures (115, 120, 125, and 130 °C) showed that for a resin with a final degree of cure exceeding 95% at the die exit, the maximum difference between the predicted values of pulling speed for a specified set of compositions may exceed 1.7 times.

Investigating the relationship between tack and degree of conversion in DGEBA-based epoxy resin cured with dicyandiamide and diuron

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Kuliaei ◽  
Iraj Amiri Amraei ◽  
Seyed Rasoul Mousavi
Keyword(s):  
Epoxy Resin ◽  
Reaction Order ◽  
Theoretical Data ◽  
Cure Kinetics ◽  
Diglycidyl Ether ◽  
Degree Of Conversion ◽  
Ozawa Method ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Kinetics Of

Abstract The purpose behind this research was to determine the optimum formulation and investigate the cure kinetics of a diglycidyl ether of bisphenol-A (DGEBA)-based epoxy resin cured by dicyandiamide and diuron for use in prepregs. First, all formulations were examined by the tensile test, and then, the specimens with higher mechanical properties were further investigated by viscometry and tack tests. The cure kinetics of the best formulation (based on tack test) in nonisothermal mode was investigated using differential scanning calorimetry at different heating rates. Kissinger and Ozawa method was used for determining the kinetic parameters of the curing process. The activation energy obtained by this method was 71.43 kJ/mol. The heating rate had no significant effect on the reaction order and the total reaction order was approximately constant ( m + n ≅ 2.1 $m+n\cong 2.1$ ). By comparing the experimental data and the theoretical data obtained by Kissinger and Ozawa method, a good agreement was seen between them. By increasing the degree of conversion, the viscosity decreased; as the degree of conversion increased, so did the slope of viscosity. The results of the tack test also indicated that the highest tack could be obtained with 25% progress of curing.

scholarly journals A Comparative Study on Cure Kinetics of Layered Double Hydroxide (LDH)/Epoxy Nanocomposites

2020 ◽  
Vol 4 (3) ◽  
pp. 111
Author(s):  
Zohre Karami ◽  
Seyed Mohammad Reza Paran ◽  
Poornima Vijayan P. ◽  
Mohammad Reza Ganjali ◽  
Maryam Jouyandeh ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Cure Kinetics ◽  
Frequency Factor ◽  
Isoconversional Methods ◽  
Epoxide Ring ◽  
Epoxy Nanocomposites ◽  
Scanning Calorimetry ◽  
Noncatalytic Reaction ◽  
Double Hydroxide ◽  
Kinetics Of

Layered double hydroxide (LDH) minerals are promising candidates for developing polymer nanocomposites and the exchange of intercalating anions and metal ions in the LDH structure considerably affects their ultimate properties. Despite the fact that the synthesis of various kinds of LDHs has been the subject of numerous studies, the cure kinetics of LDH-based thermoset polymer composites has rarely been investigated. Herein, binary and ternary structures, including [Mg0.75 Al0.25 (OH)2]0.25+ [(CO32−)0.25/2∙m H2O]0.25−, [Mg0.75 Al0.25 (OH)2]0.25+ [(NO3−)0.25∙m H2O]0.25− and [Mg0.64 Zn0.11 Al0.25 (OH)2]0.25+ [(CO32−)0.25/2∙m H2O]0.25−, have been incorporated into epoxy to study the cure kinetics of the resulting nanocomposites by differential scanning calorimetry (DSC). Both integral and differential isoconversional methods serve to study the non-isothermal curing reactions of epoxy nanocomposites. The effects of carbonate and nitrate ions as intercalating agents on the cure kinetics are also discussed. The activation energy of cure (Eα) was calculated based on the Friedman and Kissinger–Akahira–Sunose (KAS) methods for epoxy/LDH nanocomposites. The order of autocatalytic reaction (m) for the epoxy/Mg-Al-NO3 (0.30 and 0.254 calculated by the Friedman and KAS methods, respectively) was smaller than that of the neat epoxy, which suggested a shift of the curing mechanism from an autocatalytic to noncatalytic reaction. Moreover, a higher frequency factor for the aforementioned nanocomposite suggests that the incorporation of Mg-Al-NO3 in the epoxy composite improved the curability of the epoxy. The results elucidate that the intercalating anions and the metal constituent of LDH significantly govern the cure kinetics of epoxy by the participation of nitrate anions in the epoxide ring-opening reaction.

Sign in / Sign up

Export Citation Format

Share Document