Study on Curing Mechanism of Azo-Containing Twin Liquid Crystalline Epoxy Resins with Anhydride

2013 ◽  
Vol 702 ◽  
pp. 119-122
Author(s):  
Teng Fei Shen ◽  
Fa Chao Wu ◽  
Ying Juan Sun

A series of novel azo-containing twin liquid crystalline (LC) epoxy monomers were cured with anhydrides without extra catalyst and the curing kinetics was investigated by non-isothermal differential scanning calorimetry (DSC) technique. The effect of Azo group on the Curing Kinetics of Epoxy/anhydride System was investigated and the result showed that Azo group served as a catalyst to accelerate the curing reaction. The curing mechanism was confirmed by the UV-Vis spectrum.

1993 ◽  
Vol 13 (4) ◽  
pp. 571-584 ◽  
Author(s):  
C. Carfagna ◽  
E. Amendola ◽  
M. Giamberini ◽  
A. G. Filippov ◽  
R. S. Bauer

2017 ◽  
Vol 30 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Chao Chen ◽  
Yanxia Li ◽  
Yizhuo Gu ◽  
Min Li ◽  
Zuoguang Zhang

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.


2013 ◽  
Vol 702 ◽  
pp. 115-118
Author(s):  
Teng Fei Shen ◽  
Chun Feng Sun ◽  
Ying Juan Sun

A series of novel azo-containing twin liquid crystalline (LC) epoxy monomers were cured with anhydrides without extra catalyst and the curing kinetics was investigated by non-isothermal differential scanning calorimetry (DSC) technique. The results showed that the effect of phase behavior on activation energy (Ea) was very great. The chemical kinetic control and diffusion control mechanisms dominant the curing together, which gives a larger value of Ea. Azo group also served as a catalyst to accelerate the curing reaction.


Author(s):  
Alice Mititelu ◽  
Thierry Hamaide ◽  
Christian Novat ◽  
Jérôme Dupuy ◽  
Constantin N. Cascaval ◽  
...  

2010 ◽  
Vol 123-125 ◽  
pp. 955-958
Author(s):  
De Wen Zhou ◽  
Li Yan Liang ◽  
Man Geng Lu

A series of dimeric liquid crystalline (LC) epoxy monomers containing azo groups with different length of central spacers were synthesized. The mesogenic behavior of these monomers was characterized by differential scanning calorimetry(DSC), polarized optical microscopy (POM) and wide-angle X-Ray diffraction(WAXS). Like other dimeric LC epoxy monomers, the melting points, clear points and mesophase of these compounds were influenced by the carbon numbers of the central spacers. Cure kinetics of these monomers with anhydride was studied by non-isothermal DSC at different heating rates. With the increasing of conversion, the values of activation energy show a tendency to decrease. The formation and development of LC phase during curing were also studied by POM. Finally LC thermosets with nematic phase were obtained.


2011 ◽  
Vol 216 ◽  
pp. 34-38
Author(s):  
Jun Gang Gao ◽  
Xiao Na Zhang ◽  
Yong Gang Du

Three class of novel liquid crystalline epoxy resins containing azomething groups: N,N’-Bis[4-(2,3-epoxypropoxy)benzylidene]-4,4-diamino-diphenyl ether (p-BEPBDDE), N,N’-Bis[4-(2,3-epoxypropoxy)benzylidene]-4,4-diamino-diphenyl methane (p-BEPBDDM) and N,N’-Bis[(4-(2,3-epoxypropoxy)-benzyliden)-1,4- phenylene diamine] (p-BEPBPD) were synthesized and characterized. The results show that p-BEBDDE and p-BEBDDM belong to smectic texture and melting point is 239.5 and 178 oC, respectively. The p-BEPBD is nematic texture between its melting temperature (Tm) of 192 oC and clearing temperature (Ti) of 238 oC. The curing reaction can be described by Ozawa equation, and the alcohol-hydroxyl group can accelerate the curing reaction and decrease Ea in DSC experiment.


2014 ◽  
Vol 988 ◽  
pp. 31-35
Author(s):  
Jia Le Song ◽  
Chan Chan Li ◽  
Zhi Mi Zhou ◽  
Chao Qiang Ye ◽  
Wei Guang Li

Curing kinetics of MEP-15/593 system and MEP-15/593/660 system is studied by means of differential scanning calorimetry (DSC). Curing kinetic parameters are evaluated and the relationship between diluent 660 and the curing properties is investigated. The results show that the diluent 660 can not only reduce viscosity and activation energy, but also improve the degree of cure and conversion ratio.


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