The Study on Curing Kinetics of Lignin Based Epoxy Resin System Using Non-Isothermal DSC Method

2013 ◽  
Vol 788 ◽  
pp. 223-227 ◽  
Author(s):  
Ming Qiang Chen ◽  
Shao Min Liu ◽  
Feng Li ◽  
Zhong Lian Yang ◽  
Ye Zhang

The synthesis of Lignin Base Epoxy Resin was based on industrial alkali lignin, and lignin-based epoxy resin curing characteristics were analyzed using the thermal weight loss technology under the oxygen atmosphere conditions. In light of the infra-red analysis of raw materials, the curing reaction kinetic parameters of lignin-based epoxy resin system were calculated using the Kissinger-Crane and Flynn-Wall-Ozawa method, and the curing reaction kinetics model of lignin-based epoxy resin system was established. The results showed that the kinetic parameters obtained using two methods were approximate, which validated that the curing reaction was consistent with the principle of the first-order reaction model. Initial curing temperature Ti0=454.88 K, curing temperature Tp0=507.55 K, and terminal temperature Tf0=598.77 K of lignin-based epoxy resin system were obtained when the extrapolation method was applied.

2013 ◽  
Vol 690-693 ◽  
pp. 1649-1652
Author(s):  
Ai Jie Ma ◽  
Qiu Yu Zhang ◽  
You Qiang Shi

In this paper, 2-phenyl imidazole (2-PZ) microcapsule-type curing agent of epoxy resin were prepared through solvent volatilization with 2-PZ and polymethyl acrylic glycidyl ester (PGMA) as the raw materials. The micro-morphology, shape and structure of the microcapsules were studied by scanning electronic microscope (SEM) and fourier transform infrared spectrum (FT-IR). The curing kinetics of microcapsule curing agent/epoxy resin E-44 curing system were studied using TGA/DSC simultaneous thermal analyzer. Results showed that the preparation method is simple and effective and the prepared 2-PZ microcapsules have smooth surfaces and monodisperse size. And the curing kinetic study of epoxy resin system suggested epoxy resin curing temperature was rising with the increase of heating rate.


2019 ◽  
Vol 25 (4) ◽  
pp. 478-484
Author(s):  
Haoqing XU ◽  
Yuan FANG ◽  
Aizhao ZHOU ◽  
Pengming JIANG ◽  
Shi SHU ◽  
...  

Epoxy resin insulation paint was prepared with epoxy resin (E44) as binder and with proper inorganic fillers and curing agent (T31) as additives. The isothermal curing reaction process of paint was studied by the differential scanning calorimetry method (DSC), and the curves of curing reaction rate versus time of paint were obtained. The curing reaction kinetics was investigated by using the phenomenological method, and the corresponding parameters of the n-order model, autocatalytic model and Kamal model were determined by fitting the experimental data, respectively. According to the values of R2 and the sum of square due to error (SSE), a suitable curing reaction kinetic model was determined. The curing reaction mechanism of paint was ascertained by the dynamic temperature DSC method and IR spectroscopy (FTIR) method. The results show that the Kamal model can be used to describe the curing kinetics of epoxy resin paint, and the total reaction orders increase from 1.30 to 2.14. The two rate constants increase with the increase of the curing temperature. The activation energy is 90.5832 kJ/mol and 68.3733 kJ/mol respectively, and the pre-exponential factors are 6.521 × 1015 s-1 and 6.3807 × 109 s-1. The curing reaction of paint consists of two steps: the first step is the addition reaction of epoxy group and primary amine or secondary amine; the second step is the etherification reaction of epoxy group and phenolic hydroxyl or alcoholic hydroxyl. Epoxy resin insulation paint was prepared with epoxy resin (E44) as binders and with proper inorganic fillers and curing agent (T31) as additives. The isothermal curing reaction process of paint was studied by differential scanning calorimetry method (DSC), and the curves of curing reaction rate versus time of paint were obtained. The curing reaction kinetics was studied by using the phenomenological method, the corresponding parameters of the n-order model, autocatalytic model and Kamal model were determined by fitting the experimental data, respectively. According to the values of R2 and the sum of square due to error (SSE), a suitable curing reaction kinetic model was determind. The curing reaction mechanism of paint was ascertained by dynamic temperature DSC method and IR spectrogram (FTIR) method. The results show that the kamal model can be used to describe the curing kinetics of epoxy resin paint, the total reaction orders increase from 1.30 to 2.14. The results also show that the two rate constants increase with increasing curing temperature, The activation energies are 90.5832 kJ/mol and 68.3733 kJ/mol, and the pre-exponential factor are 6.521×1015 s-1 and 6.3807×109 s-1. The curing reaction of paint in two steps, the first step is the addition reaction of epoxy group and primary amine or secondary amine. The second step is the etherification reaction of epoxy group and phenolic hydroxyl or alcoholic hydroxyl.


2014 ◽  
Vol 802 ◽  
pp. 590-595 ◽  
Author(s):  
Daniel Rodrigues ◽  
Gilberto V. Concílio ◽  
Elisa Pinto da Rocha ◽  
José A. de Castro ◽  
Marcos F. de Campos

NdFeB bonded magnets are produced by compression molding and curing. Typical raw materials are mixtures of epoxy resin and Nd2Fe14B flakes, produced mostly by melt spinning. The curing temperature should be adjusted for obtaining the best in terms of mechanical properties without overheating the pressed component. High curing temperatures can strongly oxidize Nd, generating more heat, and burning may occurs. The curing reaction is exothermic, thus the actual curing temperature will depend on the cured mass. This paper investigates this heating generation during curing, using DSC experimental apparatus.


2010 ◽  
Vol 123-125 ◽  
pp. 411-414 ◽  
Author(s):  
Da Hu Yao ◽  
Kyung Bok Sun ◽  
Peng Li ◽  
Joong Hee Lee

The curing reaction of the system bisphenol-A glycidol ether epoxy resin modified by poly (ethylene glycol) (PEO) and flexible amine (D-230) as curing agent has been studied by means of differential scanning calorimetry (DSC) and thermal scanning rheometry. The curing kinetic parameters have been calculated from the non-thermal DSC curve. The kinetic analysis suggests that the two-parameter autocatalytic model is more appropriate to describe the kinetics of the curing reaction of the system. Increasing the PU content leads to an increase in the heat of curing and has a little effect on the kinetic parameters apparent activation energy (Ea), pre-exponential factor (A), and order of the reaction (m and n). The rheological properties were measured by isothermal curing evolution. Introduction of PEO flexible chains delayed the polymerization. It has been confirmed that the introduction of PEO chains in the structure of the epoxy resin increases the mobility of the molecular segment of the epoxy networks and results in the decrease in glass transition temperature.


2013 ◽  
Vol 762 ◽  
pp. 639-643
Author(s):  
Zhi Min Wan ◽  
Yu Yan Liu ◽  
Hong Jun Kang ◽  
Qi Zhu

In this paper, organic aluminum compound, aluminum tris (tetradecylacetoacetate) (Al-14) was synthesized, and its molecular structure was identified by IR spectrum. The investigation of the curing kinetic of epoxy resin system with PhS (4, 4-dihydroxydiphenylsulfone)/aluminum tris (tetradecylacetoacetate) (Al-14) latent catalysts was performed by differential scanning calorimetry (DSC) using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order and activation energy were calculated and reported. The results indicated that the curing reaction of Ep/PhS/Al-14 compand system in this experiment proceeded through an autocatalytic kinetic mechanism.


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