Rheokinetics of curing

Malkin, A. Ya.; Kulichikhin, S. G.

doi:10.1007/bfb0018003

Cited by 76 publications

(43 citation statements)

References 57 publications

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“…The gel time is one of the most important kinetic characteristics of curing, because it describes the attainment of a certain critical conversion responsible for the transition from the first to the second stage of the process 31. The gel point is characterized by the appearance in the reactive system of a macromolecule with an infinitely large molecular weight, M w → ∞.…”

Section: Resultsmentioning

confidence: 99%

Unsaturated polyester resins cure: Kinetic, rheologic, and mechanical-dynamical analysis. I. Cure kinetics by DSC and TSR

Vilas

Laza

Garay

et al. 2000

J. Appl. Polym. Sci.

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The curing reaction of a polyester resin, using methyl ethyl ketone peroxide and cobalt octoate as promoter, has been studied by differential scanning calorimetry and thermal scanning rheometry under isothermal conditions. All kinetic parameters of the curing reaction, including the reaction order, activation energy, and the rate constant, were calculated and reported using different empirical relationships. The gel time, which is defined by several criteria, was used to determine the apparent activation energy of the process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 447–457, 2001

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Section: Resultsmentioning

confidence: 99%

Unsaturated polyester resins cure: Kinetic, rheologic, and mechanical-dynamical analysis. I. Cure kinetics by DSC and TSR

Vilas

Laza

Garay

et al. 2000

J. Appl. Polym. Sci.

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“…It is noticed from the Figure 6 inset, that the reaction mixture is initially homogeneous, with the more reactive functional groups combining until the point in time where a slight decrease is observed before further increases in viscosity. This reduction in viscosity is caused by heterogeneous curing, because the reaction product is insoluble in the reacting matrix 47. It is suggested that formation of microgel particles and the start of gelation occur at this point, after which a rapid increase in the rate is observed, transitioning to two main stages of viscosity build up.…”

Section: Resultsmentioning

confidence: 99%

A thermal and rheological investigation during the complex cure of a two‐component thermoset polyurethane

Papadopoulos

Ginic‐Markovic

Clarke

2009

J of Applied Polymer Sci

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ABSTRACT:The complex cure kinetics of the reaction between oligomeric diphenylmethane diisocyanate (PMDI) and glycerol was characterized through thermal and rheological techniques. Isoconversional analysis of Differential scanning calorimetry (DSC) data resulted in the activation energy varying with conversion. Isothermal analysis gave activation energies ranging from 5 kJ/mol to 33.7 kJ/ mol, whereas nonisothermal data gave values for the activation energy ranging from 49.5 to 55 kJ/mol. Incomplete cure was evident in isothermal DSC, becoming diffusion controlled in the final stages of cure. DMA analysis on the cured material gave a glass transition temperature of 104 AE 3 C, which was evidence for vitrification of the curing system. The primary and secondary hydroxyl group reactivity was dependant on the isothermal cure temperature. Rheological studies of viscosity increase and tan d changes with time revealed a complex cure process, with primary and secondary hydroxyl reactivity also showing dependence on isothermal cure temperatures, reflecting similar results obtained from isothermal DSC studies. The independence of tan d on frequency was used to determine the point where the polymer formed an infinite network and was no longer able to flow, providing an overall activation energy attained at the gel point of 77.4 AE 4.4 kJ/mol.

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“…With this method different modules and other physical properties of material are measured as a function of temperature. Rheometry is a similar technique, in which various rheological parameters (viscosity, storage and loss modulus) can be determined by means of a rheometer (Malkin and Kulichikhin, 1991). Based on these parameters, which depend on the curing temperature and time, the whole curing process (and, in particular, gelation and vitrification) can be determined (Winter, 2003;Mravljak and Šernek, 2011).…”

Section: Uvodmentioning

confidence: 99%

“…η* is the vectorial sum of the elastic and loss component of the dynamic viscosity, and a measure of the general resistance of a material to flow as a function of the stress rate (Garnier et al, 2002). According to Malkin and Kulichikhin (1991), viscosity starts to increase near the gel point. η* as a function of temperature was used for the interpretation of the hardening behavior of the adhesive mixtures (Figure 2), and the temperature of the gel points (gelation temperatures) based on the intersection of G´ and G´´ were also compared ( Table 2).…”

Section: Rheological Response Of Lw During Curing 32 Reološki Odgovmentioning

confidence: 99%

Influence of the Addition of Urea-Formaldehyde Adhesive to Liquefied Wood on Curing

Ugovšek¹,

Šernek²

2013

Drvna ind.

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Rheokinetics of curing

Cited by 76 publications

References 57 publications

Unsaturated polyester resins cure: Kinetic, rheologic, and mechanical-dynamical analysis. I. Cure kinetics by DSC and TSR

Unsaturated polyester resins cure: Kinetic, rheologic, and mechanical-dynamical analysis. I. Cure kinetics by DSC and TSR

A thermal and rheological investigation during the complex cure of a two‐component thermoset polyurethane

Influence of the Addition of Urea-Formaldehyde Adhesive to Liquefied Wood on Curing

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