Rheology of network forming systems

Mussatti, F. G.; Macosko, Christopher W.

doi:10.1002/pen.760130312

Cited by 108 publications

(26 citation statements)

References 9 publications

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“…Equation ( 3 ) is the so-called Arrhenius type relationship, with R = 1.986 cal/mol/K, the ideal gas constant, and E,, the activation energy for viscous flow. Equations ( 2 ) and ( 3 ) Results of the linear least squares fit of Eqs. ( 2 ) and ( 3 ) to the experimental data (see Tables I1 and 111) are tabulated in Table V.…”

Section: Temperature Dependent Viscositiesmentioning

confidence: 99%

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Chemorheology of an epoxy resin system under isothermal curing

Hou¹,

Huang

Hinkley

1990

J of Applied Polymer Sci

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SynopsisThe chemorheological properties of a commercial Hercules 3501-6 resin system were studied under isothermal curing conditions between 375 and 435 K. For cure temperatures 2 385 K, the storage modulus curing curves, G'( t ) , exhibited abrupt changes in slope which occurred at various times depending on the curing temperatures. These slope changes were attributed to the onset of gelation. Crossover points between G'( t ) and G"( t ) curves were observed for curing temperatures 2 400 K. The gelation and the crossover points obtained from the chemorheological measurements, therefore, defined two characteristic resin states during cure. Although gelation theory did not predict them correctly, the degree of cure in each of these states was approximately the same for every cure temperature. The temperature dependency of the viscosities in the characteristic resin states, and the rate constants of increase in moduli a t different stages of curing were analyzed.Various G'( t ) and G"( t ) isothermal curing curves were also shown to be capable of being superimposed to one another by the principle of time-temperature superposition. The resultant shift factors a,( T ) and a,( T ) were shown to follow Arrhenius type relationships. Values of the activation energy suggested that the reaction kinetics, instead of the diffusion mechanism, was the limiting step in the overall resin advancement for cure at temperatures 2 385 K.

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Section: Temperature Dependent Viscositiesmentioning

confidence: 99%

“…Equations ( 2 ) and ( 3 ) Results of the linear least squares fit of Eqs. ( 2 ) and ( 3 ) to the experimental data (see Tables I1 and 111) are tabulated in Table V. It is noted that q*( T ) can be more accurately described by the Arrhenius type of temperature dependency in both characteristic resin states.…”

Section: Temperature Dependent Viscositiesmentioning

confidence: 99%

Chemorheology of an epoxy resin system under isothermal curing

Hou¹,

Huang

Hinkley

1990

J of Applied Polymer Sci

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“…The apparent activation energy of the reaction could also be determined from the slope of the tangent to the GЈ ϭ f(t) curve after this induction period (E a2 ) 17,18,21,23 because the temperature dependence of these slopes obeyed an Arrhenius-type equation. The apparent activation energies estimated in this way for the different functionalities are shown in Table II.…”

Section: Kinetics Of the Interchain Crosslinking Reactionmentioning

confidence: 99%

Rheological behavior of reactive miscible polymer blends: Influence of mixing and annealing before crosslinking

Serra

Bouquey

Schlatter

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:We followed crosslinking reactions in the blends of two miscible reactive polymers by either torque rheometry or dynamic rheological measurements. Functional polymers with controlled glass-transition temperatures (T g 's), chain lengths, and number of reactive groups per chain were synthesized by bulk radical polymerization. The blends were prepared either in a batch mixer or directly in the parallel plate geometry of a dynamic rheometer. Because of the low T g of the blend components, it was possible to separate the mixing step from the crosslinking reaction, which was followed by small amplitude dynamic measurements at a higher temperature. The kinetics of the crosslinking reaction were determined by the study of the variations of the storage modulus (GЈ) as a function of the reaction time. In this study, we focused on investigating the influence of blend composition, crosslinking reaction temperature, and amount of shear generated during the mixing step on the reaction kinetics. The influence of annealing time after the preshear step was also investigated. We found that the mixing procedure in the internal mixer produced homogeneous blends for which GЈ was dependent on the reaction time. Moreover, the reaction rate increased as the temperature and the chain functionality increased. A first approach showed that reduced variables could be defined from GЈ and reaction time with the initial concentration of the functional units to obtain a master curve independent of the species concentration. For blends prepared directly between the parallel plates of the dynamic rheometer, GЈ and the subsequent reaction rate were strongly dependent on the amount of shear generated during the mixing step. However, at high enough shear, the blend was perfectly mixed and the increase in GЈ versus reaction time was comparable to that obtained for the blend prepared in the internal mixer. Surprisingly, the higher the annealing time was, the lower the increase in GЈ was. However, we could explained this by considering the fact that the reaction started during the annealing step, which therefore, led to a thin crosslinked layer, which prevented any further diffusion of the polymer chains.

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“…The kinetic model based on the method of calorimetry DSC does not have a direct correlation with the mechanical properties of the curing product. Although both Craig [8] and Mussatti and Macoska [9] have developed a kinetic model for predicting viscosity and modulus during the curing reaction, the application of this model is limited because it does not include the resin-filler interreac- tion. With this problem in mind, Hsich [10,11] developed a new kinetic model based on the nonequilibrium thermodynamic fluctuation theory and successfully studied the cure behaviour of a natural rubber-sulphur-carbon black system.…”

Section: Introductionmentioning

confidence: 99%

Curing studies on epoxy system with fillers

Chune

1989

J Mater Sci

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A dynamic torsional vibration method has been developed and used to investigate the isothermal cure processes of a thermosetting resin containing fillers. The isothermal cure behaviour of an epoxy resin-imidazole-SiO2 system at various temperatures and various SiO 2 filler Ioadings was predicted using non-equilibrium thermodynamic fluctuation theory. There was good agreement between the theoretical prediction and experimental curing curves. It has been shown that activation energy of the cure reaction remained almost a constant value of AH = 76.6 x 103 J mo1-1 within the range 0 to 120phr SiO2 filler Ioadings, but SiO2 filler has a complicated effect on the rate of the cure reaction.

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Rheology of network forming systems

Cited by 108 publications

References 9 publications

Chemorheology of an epoxy resin system under isothermal curing

Chemorheology of an epoxy resin system under isothermal curing

Rheological behavior of reactive miscible polymer blends: Influence of mixing and annealing before crosslinking

Curing studies on epoxy system with fillers

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