Diffusion-controlled reaction mechanisms during cure in polycarbonate-modified epoxy networks

Su, Chean-Cheng; Woo, Eamor M.

doi:10.1002/(sici)1099-0488(19970930)35:13<2141::aid-polb14>3.0.co;2-4

Cited by 16 publications

(13 citation statements)

References 19 publications

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“…In the early stage of cure (before gel or vitrification), the cure reactions are mainly controlled by the kinetic rate of the chemical reaction. Subsequently, the cure reaction reaches higher conversions, where the reaction gradually becomes diffusion controlled 19, 25–27. When the system reaches the gel point, a network is gradually formed with an infinite molecular weight and the viscosity of the system would increase significantly, and the system is transformed from a liquid/rubbery state to a glassy state.…”

Section: Resultsmentioning

confidence: 99%

Cure kinetic study of carbon nanofibers/epoxy composites by isothermal DSC

Xie

Liu

Sun

et al. 2005

J of Applied Polymer Sci

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An investigation was carried out into the cure kinetics of carbon nanofibers (CNF)/epoxy composites, composed of tetraglycidyl-4,4Ј-diaminodiphenylmethane (TGDDM) resin and 4,4Ј-diaminodiphenylsulfone (DDS) as a curing agent. The experimental data for both neat system and CNF/epoxy composites revealed an autocatalytic behavior. Analysis of DSC data indicated that the presence of carbon nanofibers had only a negligible effect on the cure kinetics of the epoxy. Kinetic analysis was performed using the phenomenological model of Kamal and two diffusion factors were introduced to describe the cure reaction in the latter stage. Activation energies and kinetic parameters were determined by fitting experimental data. Comparison between the two diffusion factors was performed, showing that the modified factor was successfully applied to the experimental data over the whole curing temperature range.

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Section: Resultsmentioning

confidence: 99%

Cure kinetic study of carbon nanofibers/epoxy composites by isothermal DSC

Xie

Liu

Sun

et al. 2005

J of Applied Polymer Sci

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“…Apparently, the mechanistic model describes the cure kinetics well but diffusion of species might be a control factor in the vitrified state, which limits the cure reactions from going any further. After vitrification, progress in the cure reaction almost comes to a stop, therefore the extent of cure is limited 20,21) . This indicates a phenomenon of diffusion control due to vitrification.…”

Section: Cure Kinetics In Dgeba/peo Systemsmentioning

confidence: 99%

Cure behavior of an interpenetrating diglycidyl ether of bisphenol A/poly(ethylene oxide) miscible system

Horng

Woo²

1998

Angew. Makromol. Chem.

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Differential scanning calorimetry (DSC) was performed to investigate the cure behavior of epoxy networks of diglycidyl ether of bisphenol A/poly(ethylene oxide) (DGEBA/PEO) cured with 4,4'‐diaminodiphenyl sulfone (DDS). An interesting miscibility has been recently reported for DGEBA/PEO networks of a semi‐interpenetrating structure cured with aromatic amine. This study focused on the cure behavior and effects of miscible polymer diluents on cure kinetics. The physical miscible state between the polymer and epoxy was found to exert no alteration on the cure mechanism, which remained to be autocatalytic for DDS amine‐curing of all DGEBA/PEO mixtures as well as the pure DGEBA. The PEO component, being in a miscible state with the epoxy/DDS throughout the cure, acted as a diluent for the reactive DGEBA epoxy and DDS components. The dilution effect could be partially compensated by raising the DDS/epoxy ratio in proportion to increased PEO fraction in DGEBA/PEO/DDS mixtures.

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“…1 The curing kinetics of tetraglycidyl-4,4Ј-diaminodiphenylmethane (TGDDM) cured with 4,4Јdiaminodiphenylsulfone (DDS) that are commonly used as a polymeric matrix in high-performance composites employed in the aircraft and spacecraft industries has been studied by means of differential scanning calorimetry (DSC). [15][16][17][18] Although there have been several reports on the kinetics of TGDDM/DDS systems blended with graphite or carbon fibers, 3,19 very few efforts have been made to study the influence of CNTs on the cure reactions of tetrafunctional epoxy resins. In this work, we use isothermal DSC to study the cure kinetics of TGDDM and DDS as a curing agent, as well as its nanocomposites with mutiwalled carbon nanotubes (MWNTs).…”

Section: Introductionmentioning

confidence: 99%

Cure kinetics of carbon nanotube/tetrafunctional epoxy nanocomposites by isothermal differential scanning calorimetry

Xie

Liu

Zhou

et al. 2004

J Polym Sci B Polym Phys

141

103

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The cure kinetics of tetraglycidyl‐4,4′‐diaminodiphenylmethane (TGDDM) and 4,4′‐diaminodiphenylsulfone (DDS) as a cure agent in nanocomposites with multiwalled carbon nanotubes (MWNTs) have been studied with an isothermal differential scanning calorimetry (DSC) technique. The experimental data for both the neat TGDDM/DDS system and for epoxy/MWNTs nanocomposites showed an autocatalytic behavior. Kinetic analysis was performed with the phenomenological model of Kamal and a diffusion control function was introduced to describe the cure reaction in the later stage. Activation energies and kinetic parameters were determined by fitting experimental data. For MWNTs/epoxy nanocomposites, the initial reaction rates increased and the time to the maximum rate decreased with increasing MWNTs contents because of the acceleration effect of MWNTs. The values of the activation energies for the epoxy/MWNTs nanocomposites were lower than the values for the neat epoxy in the initial stage of the reaction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3701–3712, 2004

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Diffusion-controlled reaction mechanisms during cure in polycarbonate-modified epoxy networks

Cited by 16 publications

References 19 publications

Cure kinetic study of carbon nanofibers/epoxy composites by isothermal DSC

Cure kinetic study of carbon nanofibers/epoxy composites by isothermal DSC

Cure behavior of an interpenetrating diglycidyl ether of bisphenol A/poly(ethylene oxide) miscible system

Cure kinetics of carbon nanotube/tetrafunctional epoxy nanocomposites by isothermal differential scanning calorimetry

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