scholarly journals Curing Kinetics of Hybrid Networks Composed of Benzoxazine and Multifunctional Novolac Epoxy

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wu Ke ◽  
Wang Rumin ◽  
Zeng Jinfang
Keyword(s):  
Thermogravimetric Analysis ◽  
Curing Kinetics ◽  
Hybrid Networks ◽  
Hybrid Network ◽  
Scanning Calorimetry ◽  
Autocatalytic Model ◽  
Novolac Epoxy ◽  
Kinetics Of ◽  
Mixture System ◽  
Reactive Mechanism

A novel hybrid network composed of benzoxazines (BZ) and novolac epoxy resin (F-51) was prepared successfully. Thermal properties, curing kinetics, and decomposition process were studied using isothermal differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in this paper. The reactive mechanism of F-51/BZ mixture system is different from the BZ homopolymers at low temperatures; two resin systems follow the autocatalytic model mainly at high temperatures. Thermogravimetric analysis indicates that F-51 can have no significant effect on thermal degradation temperatures and on increasing char yield.

Curing Kinetics of Cyano Functionalized Benzoxazine

2011 ◽  
Vol 233-235 ◽  
pp. 2337-2340
Author(s):  
Wen Jin Chen ◽  
Xiao Bo Liu
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Theoretical Calculations ◽  
Curing Kinetics ◽  
High Thermal Stability ◽  
Order Model ◽  
Scanning Calorimetry ◽  
Autocatalytic Model ◽  
Kinetics Of

A multifunctional benzoxazine monomer (BZCN) was synthesized, which has several outstanding properties, such as high thermal stability and high glass transition. To better understand the curing kinetics of BZCN, isothermal differential scanning calorimetry measurements were used to determine the kinetic parameters and the kinetic models of the curing processes of benzoxazine monomer with cyano functionality. The result shows the mechanism of the curing reaction of BZCN exhibits autocatalytic model, but doesn’t meet nth-order model. Owing to the effects of catalysis of cyano functionality, the activation energy is 89.65KJ•mol-1and the total order of reaction is 1.84, which is quite different from that of normal benzoxazine. The theoretical calculations matched reasonably well with the experimental results.

scholarly journals The Curing Kinetics of Multiscale [Ni(EDTA)]-2 Intercalated Zn-Al Layered Double Hydroxides: Glass Fiber–Epoxy Composite Prepreg

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Reza Darvishi ◽  
Mahdi Darvishi ◽  
Ali Moshkriz
Keyword(s):  
Glass Fiber ◽  
Layered Double Hydroxides ◽  
Cure Kinetics ◽  
Curing Kinetics ◽  
Scanning Calorimetry ◽  
Curing Behavior ◽  
Autocatalytic Model ◽  
Experimental Findings ◽  
Double Hydroxides ◽  
Kinetics Of

In the present research, the effect of Zn2Al layered double hydroxides (LDH) and nickel (II)-EDTA complex intercalated LDH (LDH-[Ni(EDTA)]-2) on the cure kinetics of glass fiber/epoxy prepreg (GEP) was explored using nonisothermal differential scanning calorimetry (DSC). The results showed that LDH caused a shift in the cure temperature toward lower temperatures while accelerating the curing of epoxy prepregs. The use of LDH-[Ni(EDTA)]-2 more profoundly influenced the acceleration of the curing process. The curing kinetics of prepregs was assessed through the differential isoconversional Friedman (FR) technique and the integration method of Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS). A decrease was detected in the E α value of glass fiber/LDH-[Ni(EDTA)]-2/epoxy (GELP) and glass fiber/LDH-[Ni(EDTA)]-2/epoxy (GELNiP) prepregs at small cure degrees relative to GEP, suggesting the catalytic effect of LDH or LDH-[Ni(EDTA)]-2 on the initial epoxy/amine reaction. Furthermore, LDH-[Ni(EDTA)]-2 performed better due to the catalyst role of nickel (II). Moreover, the activation energy exhibited lower reliance on the degree of conversion in the cases of GELP and GELNiP rather than pure epoxy prepregs. An autocatalytic model was used to evaluate the curing behavior of the system. Based on the results, the curing reaction of the epoxy prepreg can be described by the autocatalytic Šesták-Berggren model even after the incorporation of LDH or LDH-[Ni(EDTA)]-2. The kinetic parameters of the autocatalytic model (such as E α , A , m , n ) and the equations explaining the curing behavior of prepregs were introduced as well whose predictions were in line with the experimental findings.

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.

Study on Curing Kinetics of MEP-15/593/660 System

2014 ◽  
Vol 988 ◽  
pp. 31-35
Author(s):  
Jia Le Song ◽  
Chan Chan Li ◽  
Zhi Mi Zhou ◽  
Chao Qiang Ye ◽  
Wei Guang Li
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Kinetic Parameters ◽  
Curing Kinetics ◽  
Conversion Ratio ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Curing Kinetic ◽  
The Relationship ◽  
Kinetics Of

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.

Synthesis and Thermal Stability of Unsaturated Polyamides

1992 ◽  
Vol 4 (2) ◽  
pp. 67-71
Author(s):  
N. R. Patel ◽  
N. Z. Patel ◽  
R. M. Patel
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Scanning Calorimetry ◽  
Aromatic Diamines ◽  
Good Thermal Stability ◽  
Kinetics Of Decomposition ◽  
Glutaconic Acid ◽  
Kinetics Of ◽  
Thermal Stability Of

Unsaturated polyamides were prepared by condensing /3(4-ethoxyphenyl) glutaconic acid with various aromatic diamines. The polycondensates were characterized by IR spectroscopy, vapor phase osmometry, thermogravimetric analysis, differential scanning calorimetry and elemental analysis. All resins were found to decompose in the range '-210-600 °C. The kinetics of decomposition were studied. The results indicated that the resins possess reasonably good thermal stability.

Mechanical properties of jute fiber–reinforced UP/PU hybrid network composites

2019 ◽  
Vol 27 (9) ◽  
pp. 546-556 ◽  
Author(s):  
Richa Singh ◽  
B Singh ◽  
Hina Tarannum
Keyword(s):  
Mechanical Properties ◽  
Unsaturated Polyester ◽  
Fiber Surface ◽  
Mechanical Analysis ◽  
Hybrid Networks ◽  
Hybrid Network ◽  
Matrix Composites ◽  
Scanning Calorimetry ◽  
Jute Fibers ◽  
Polyester Matrix

Hybrid networks (unsaturated polyester–polyurethane (UP/PU)) of UP resin and PU prepolymer were synthesized and characterized for their phase miscibility with the help of Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis (DMA), and atomic force microscopy. The existence of hydrogen bonded –NH groups, broadened glass transition region, and reduced phase domains evidenced the formation of intermixed phase when compared with the parent UP. The optimum mechanical properties of UP/PU hybrid networks were observed at ∼5 wt% PU content. The composites made from treated jute fibers and UP/PU hybrid networks were evaluated for their physico-mechanical properties. DMA curves showed that UP/PU matrix composites had ∼20% higher storage modulus and ∼17% lower tan δ than the polyester matrix composites. The tensile and flexural strengths of these composites were increased by ∼13% and ∼40%, respectively. During accelerated aging, the UP/PU matrix composites retained ∼15% more tensile strength than the polyester matrix composites. Fractographic evidence, such as resin adherence onto the pullout fiber surface, fiber breakage, and adequate adhesion between the jute fibers and the resin, supported the superior properties of UP/PU matrix composites to polyester matrix composites.

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.

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