Investigation of Curing Kinetics of Azo-Containing Twin Liquid Crystalline Epoxy Resins with Anhydride

2013 ◽  
Vol 702 ◽  
pp. 115-118
Author(s):  
Teng Fei Shen ◽  
Chun Feng Sun ◽  
Ying Juan Sun
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Curing Kinetics ◽  
Chemical Kinetic ◽  
Diffusion Control ◽  
Kinetic Control ◽  
Control Mechanisms ◽  
Scanning Calorimetry ◽  
Kinetics Of ◽  
And Diffusion

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.

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
Keyword(s):  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Curing Kinetics ◽  
Scanning Calorimetry ◽  
Curing Reaction ◽  
Azo Group ◽  
Liquid Crystalline Epoxy ◽  
Curing Mechanism ◽  
Kinetics Of

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.

Curing kinetics of liquid-crystalline epoxy resins

1993 ◽  
Vol 13 (4) ◽  
pp. 571-584 ◽  
Author(s):  
C. Carfagna ◽  
E. Amendola ◽  
M. Giamberini ◽  
A. G. Filippov ◽  
R. S. Bauer
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Curing Kinetics ◽  
Liquid Crystalline Epoxy ◽  
Kinetics Of

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.

Curing kinetics of liquid-crystalline epoxy resins with inverse reactivity ratios

2000 ◽  
Vol 201 (12) ◽  
pp. 1209-1213 ◽  
Author(s):  
Alice Mititelu ◽  
Thierry Hamaide ◽  
Christian Novat ◽  
Jérôme Dupuy ◽  
Constantin N. Cascaval ◽  
...  
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Curing Kinetics ◽  
Reactivity Ratios ◽  
Liquid Crystalline Epoxy ◽  
Kinetics Of

Dimeric Liquid Crystalline Epoxy Resins Containing Azo Group: Mesogenic Behavior and Curing with Anhydride

2010 ◽  
Vol 123-125 ◽  
pp. 955-958
Author(s):  
De Wen Zhou ◽  
Li Yan Liang ◽  
Man Geng Lu
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Cure Kinetics ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Azo Group ◽  
Kinetics Of

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.

Oxidation of Copper Sulfides in Aqueous Ammonia. III. Kinetic Characteristics

1979 ◽  
Vol 32 (12) ◽  
pp. 2597 ◽  
Author(s):  
AO Filmer ◽  
AJ Parker ◽  
BW Clare ◽  
LGB Wadley
Keyword(s):  
Aqueous Ammonia ◽  
Sulfide Oxidation ◽  
Metal Sulfide ◽  
Diffusion Control ◽  
Sulfate Ions ◽  
Kinetics Of Oxidation ◽  
Copper Sulfides ◽  
Shrinking Core ◽  
Kinetics Of ◽  
And Diffusion

The kinetics of oxidation with oxygen of chalcocite, Cu2S, to CuS in buffered aqueous ammonia at pH 10.5 at 30� can be modeled approximately by a shrinking core of Cu2S within a thickening shell of CuxS (x ≥ 1). The Cu2S core offers partial cathodic protection to the CuxS and diffusion of Cu+ through CuxS controls the rate of reaction. The kinetics of oxidation of covellite, CuS, to Cu2+, sulfur and sulfate ions in the same solvent can be modeled by a shrinking core of CuS surrounded by a shrinking sphere of CuyS (y < 1) which is much less effectively protected cathodically by the CuS core. Oxidation of CuS is subject to mixed chemical and diffusion control. Rates of oxidation of NiS and of CuS, in the presence and absence of tetrachloroethene and ammonium sulfate, show that, whether sulfur is a major oxidation product or not, the presence of sulfur has very little, if any, influence on the rate or mechanism of oxidation. This is contrary to current ideas on metal sulfide oxidation.

scholarly journals Single-sided NMR for the measurement of the degree of cross-linking and curing

2018 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Norbert Halmen ◽  
Christoph Kugler ◽  
Eduard Kraus ◽  
Benjamin Baudrit ◽  
Thomas Hochrein ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Curing Kinetics ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
First Results ◽  
Non Destructive ◽  
Kinetics Of ◽  
Good Agreement

Abstract. The degree of cross-linking and curing is one of the most important values concerning the quality of cross-linked polyethylene (PE-X) and the functionality of adhesives and resin-based components. Up to now, the measurement of this property has mostly been time-consuming and usually destructive. Within the shown work the feasibility of single-sided nuclear magnetic resonance (NMR) for the non-destructive determination of the degree of cross-linking and curing as process monitoring was investigated. First results indicate the possibility of distinguishing between PE-X samples with different degrees of cross-linking. The homogeneity of the samples and the curing kinetics of adhesives can also be monitored. The measurements show good agreement with reference tests (wet chemical analysis, differential scanning calorimetry, dielectric analysis). Furthermore, the influence of sample temperature on the characteristic relaxation times can be observed.

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