scholarly journals Kinetic Analysis of the Curing Process of Biobased Epoxy Resin from Epoxidized Linseed Oil by Dynamic Differential Scanning Calorimetry

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1279
Author(s):  
Diego Lascano ◽  
Alejandro Lerma-Canto ◽  
Vicent Fombuena ◽  
Rafael Balart ◽  
Nestor Montanes ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Linseed Oil ◽  
Single Step ◽  
Curing Process ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Step Process ◽  
Epoxidized Linseed Oil

The curing process of epoxy resin based on epoxidized linseed oil (ELO) is studied using dynamic differential scanning calorimetry (DSC) in order to determine the kinetic triplet (Ea, f(α) and A) at different heating rates. The apparent activation energy, Ea, has been calculated by several differential and integral isoconversional methods, namely Kissinger, Friedman, Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS) and Starink. All methods provide similar values of Ea (between 66 and 69 kJ/mol), and this shows independence versus the heating rate used. The epoxy resins crosslinking is characterized by a multi-step process. However, for the sake of the simplicity and to facilitate the understanding of the influence of the oxirane location on the curing kinetic, this can be assimilated to a single-step process. The reaction model has a high proportion of autocatalytic process, fulfilling that αM is between 0 and αp and αM < αp∞. Using as reference the model proposed by Šesták–Berggren, by obtaining two parameters (n and m) it is possible to obtain, on the one hand, the kinetic parameters and, on the other hand, a graphical comparison of the degree of conversion, α, versus temperature (T) at different heating rates with the average n and m values of this model. The good accuracy of the proposed model with regard to the actual values obtained by DSC gives consistency to the obtained parameters, thus suggesting the crosslinking of the ELO-based epoxy has apparent activation energies similar to other petroleum-derived epoxy resins.

scholarly journals Fully Biobased Epoxy Resins from Fatty Acids and Lignin

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1158 ◽  
Author(s):  
Pablo Ortiz ◽  
Richard Vendamme ◽  
Walter Eevers
Keyword(s):  
Epoxy Resin ◽  
Renewable Resources ◽  
Epoxy Resins ◽  
Linseed Oil ◽  
Tensile Tests ◽  
Present System ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Commodity Chemicals ◽  
Epoxidized Linseed Oil

The use of renewable resources for plastic production is an imperious need for the reduction of the carbon footprint and the transition towards a circular economy. With that goal in mind, fully biobased epoxy resins have been designed and prepared by combining epoxidized linseed oil, lignin, and a biobased diamine derived from fatty acid dimers. The aromatic structures in lignin provide hardness and strength to an otherwise flexible and breakable epoxy resin. The curing of the system was investigated by infrared spectroscopy and differential scanning calorimetry (DSC). The influence of the different components on the thermo-mechanical properties of the epoxy resins was analyzed by DSC, thermal gravimetric analysis (TGA), and tensile tests. As the content of lignin in the resin increases, so does the glass transition, the Young’s modulus, and the onset of thermal degradation. This correlation is non-linear, and the higher the percentage of lignin, the more pronounced the effect. All the components of the epoxy resin being commodity chemicals, the present system provides a realistic opportunity for the preparation of fully biorenewable resins at an industrial scale.

An improved simplified approach for curing kinetics of epoxy resins by nonisothermal differential scanning calorimetry

2017 ◽  
Vol 30 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Chao Chen ◽  
Yanxia Li ◽  
Yizhuo Gu ◽  
Min Li ◽  
Zuoguang Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Epoxy Resin ◽  
Kinetic Parameters ◽  
Epoxy Resins ◽  
Curing Kinetics ◽  
Scanning Calorimetry ◽  
Simplified Approach ◽  
Curing Kinetic ◽  
Autocatalytic Curing ◽  
Kinetics Of

The curing kinetics of two different types of commercial epoxy resins were investigated by means of nonisothermal differential scanning calorimetry (DSC) in this work. The complex curve of measured heat flow of CYCOM 970 epoxy resin was simplified with the method of resolution of peak. Two typical autocatalytic curing reaction curves were gained and the kinetic parameters of the curing process were demonstrated by combination of those two reactions. The Kissinger method was adopted to obtain the values of the activation energy. The parameters of curing kinetic model were acquired according to the fitting of Kamal model. Isothermal DSC curve of CYCOM 970 epoxy resin obtained using the experimental data shows a good agreement with that theoretically calculated. Then, 603 epoxy resin was investigated by the simplified method and the kinetic parameters were received through the same procedure. The nonisothermal DSC curve tested according to the recommended cure cycle of 603 epoxy resin is also consistent with the calculated results. This improved simplified approach provides an effective method to analyze the curing kinetics of the epoxy resins with complex DSC curves as similar to this study.

scholarly journals Cure Kinetics and Properties of Blends of Epoxy Resins with Polyethersulfone

CONVERTER ◽  
2021 ◽  
pp. 476-481
Author(s):  
Tiantian Feng, Et al.
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Heat Resistance ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Cure Kinetics ◽  
Scanning Calorimetry

In this article,polyethersulfone and flourene-coating epoxy resin were utilized tomodify both the toughness and the mechanical properties of traditional epoxy resins. The cure kineticsand the thermal stabilityof the resultedblends were tested by differential scanning calorimetry technology and thermogravimetric analysis, respectively. Additionally, the mechanical properties of resulted thermosets were discussed after tested by Dynamic Thermomechanical Analyzer.When compared to the traditional epoxides, the obtained blends exhibit much better heat resistance, thermal stability and mechanical properties.

scholarly journals Kinetic Analysis of the Curing of a Partially Biobased Epoxy Resin Using Dynamic Differential Scanning Calorimetry

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 391 ◽  
Author(s):  
Diego Lascano ◽  
Luis Quiles-Carrillo ◽  
Rafael Balart ◽  
Teodomiro Boronat ◽  
Nestor Montanes
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
Curing Kinetics ◽  
Reaction Model ◽  
Diglycidyl Ether ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Model Free

This research presents a cure kinetics study of an epoxy system consisting of a partially bio-sourced resin based on diglycidyl ether of bisphenol A (DGEBA) with amine hardener and a biobased reactive diluent from plants representing 31 wt %. The kinetic study has been carried out using differential scanning calorimetry (DSC) under non-isothermal conditions at different heating rates. Integral and derivative isoconversional methods or model free kinetics (MFK) have been applied to the experimental data in order to evaluate the apparent activation energy, Ea, followed by the application of the appropriate reaction model. The bio-sourced system showed activation energy that is independent of the extent of conversion, with Ea values between 57 and 62 kJ·mol−1, corresponding to typical activation energies of conventional epoxy resins. The reaction model was studied by comparing the calculated y(α) and z(α) functions with standard master plot curves. A two-parameter autocatalytic kinetic model of Šesták–Berggren [SB(m,n)] was assessed as the most suitable reaction model to describe the curing kinetics of the epoxy resins studied since it showed an excellent agreement with the experimental data.

scholarly journals Improved Processing and Properties for Polyphenylene Oxide Modified by Diallyl Orthophthalate Prepolymer

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2016
Author(s):  
Honghua Wang ◽  
Qilin Mei ◽  
Yujie Ding ◽  
Zhixiong Huang ◽  
Minxian Shi
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Separation ◽  
Dilution Effect ◽  
Gradual Decrease ◽  
Gel Point ◽  
Dynamic Mode ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
Polyphenylene Oxide

Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology in separated phases were also studied. Differential scanning calorimetry (DSC) results showed that the cure degree of the reactively plasticized DAOP prepolymer was reduced with increasing PPO due to the dilution effect. The increasing amount of the DAOP prepolymer led to a gradual decrease in the viscosity of the blends and the rheology behavior was consistent with the chemical gelation of DAOP prepolymer in blends. This indicated that the addition of the DAOP prepolymer effectively improved processability. The phase separation occurring during curing of the blend and the transition from the static to dynamic mode significantly influences the development of the morphology of the blend corresponding to limited evolution of the conversion around the gel point.

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.

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