Combined Effects of Hot Curing Conditions and Reaction Heat on Rubber Vulcanization Efficiency and Vulcanizate Uniformity

Wang, Xiaoxia; Jia, Yuxi; Lü, Feng; An, Lijia

doi:10.1002/mats.200800101

Cited by 9 publications

(5 citation statements)

References 22 publications

(43 reference statements)

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“…The measured temperatures, the experimentally determined concentration of cross-links (section ), and the explicit finite difference method solution results for HPAB/DCP compounds (compounds 1−3 in Table ) are presented in Figure (temperature) and Figure (concentration of cross-links). The methodology and the flow chart of the numerical simulation for integrated analysis is outlined in Figure analogously to Jia et al The agreement of the explicit finite difference method solution of DEB, DMBM, and DMBC with the experimental values was poorer for the concentration of cross-links in comparison to temperature (Figures and ), as in the first case a noticeable error occurs during the cross-linking process compound sampling. By comparison of the overall variance (statistical dispersion, calculated as the square of the summated differences between the model predictions and the experimental values) it was concluded, that the agreement was good regardless of the compound in question.…”

Section: Resultsmentioning

confidence: 95%

Cross-Linking of Polymers: Kinetics and Transport Phenomena

Likozar

Krajnc

2011

Ind. Eng. Chem. Res.

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The cross-linking process of a complex system was studied at elevated temperature. Partially hydrogenated poly(acrylonitrile-co-1,3-butadiene)/dicumyl peroxide compound was selected as a representative complex polymer/cross-linking agent system. On the basis of the mechanisms of cross-linking reactions, an expression relating reaction rates and population balance equations with rheologically determined concentration of cross-links was applied. Consequently the Eyring equation reflecting the effect of the self-diffusion on reaction rate constants was utilized and was further integrated into the classical Arrhenius equation for reaction rate constants. Diffusion coefficients acknowledging the mutual diffusion were estimated according to the free-volume theory, whereas thermodynamic properties governing the heat transfer, i.e. density, heat capacity, and thermal conductivity, were determined from independent measurements. Plateau storage modulus variation was monitored within the linear viscoelastic regime by dynamic mechanical analysis. Compounds with different initial peroxide concentrations were chosen for the study of the correspondence between model predictions and experimental observations, which proved to be very good.

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Section: Resultsmentioning

confidence: 95%

Cross-Linking of Polymers: Kinetics and Transport Phenomena

Likozar

Krajnc

2011

Ind. Eng. Chem. Res.

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“…BLOCK 1: for each node of the item (already discretized by means of FEMs) at fixed values of the input parameters T n (curing agent temperature) and t c (curing time), temperature profiles are evaluated by solving numerically a Fourier's heat transmission problem in two‐dimensions [45–51]. Since, closed form solutions are rarely available and usually refer to simple geometries, a FEM [52] discretization is needed in the most general case.…”

Section: The Kinetic Numerical Model: a Reviewmentioning

confidence: 99%

“…In the first phase, elastomers are exposed to high temperatures in order to activate crosslinking and thus vulcanization, whereas in the second phase rubber is kept to ambient temperature through air and/or water. In the most general case of 2D items, temperature profiles for each point of the element are obtained solving numerically Fourier's heat equation law [45–51]: where ρ p , c

_{p}^{p}

, and λ p are EPDM density, specific heat capacity, and heat conductivity, respectively; Δ H r (kJ/mol) is rubber specific heat (enthalpy) of reaction and r p [mol/(m 3 sec)] is the rate of crosslinking.…”

Section: The Kinetic Numerical Model: a Reviewmentioning

confidence: 99%

Kinetic finite element model to optimize sulfur vulcanization: Application to extruded epdm weather‐strips

Milani¹

2012

Polymer Engineering & Sci

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A numerical two-phase approach based on experimental scorch curve data fitting, to predict the optimal exposure time and cure temperature of extruded thick items is applied for the study of a real weather-strip. In the first phase, an existing single equation kinetic model is used to predict the crosslinking density under sulfur vulcanization at variable temperatures. The model requires the calibration of only three kinetic constants. The variation with respect to temperature of such parameters is then evaluated by means of two experimental cure curves performed at two different temperatures. In the second phase, kinetic reaction parameters are implemented in finite element software, to perform thermal analyses on an extruded weatherstrip. Once evaluated the final mechanical properties of the item point by point, a set of compression tests is numerically simulated, assuming that the rubber behaves as a Mooney-Rivlin material under the large deformations. Elastic properties of the item are evaluated as a function of the vulcanization degree evaluated in the second phase. It is found that suboptimal vulcanizations result into lower elastic moduli and hence great deformability, sometimes incompatible with real scale engineering applications. POLYM. ENG.

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“…The governing equation of the temperature field can be derived by Galerkin method [16], as shown below…”

Section: Governing Equation Of Temperature Fieldmentioning

confidence: 99%

Kinetic Modelling and Finite Element Simulation of Natural Rubber Non-Isothermal Vulcanization

Yao

Jia

Wang

2011

AMR

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On the basis of kinetic equations constructed in the isothermal vulcanization of natural rubber (NR), a new numerical computation expression of cure degree under non-isothermal conditions is established by the incremental method. The numerical simulation of the vulcanization stage in injection molding processes of NR is performed by the finite element method, and then the time and position-dependent changes in the cure degree are analyzed numerically. The simulation results are consistent with the results described in the previous literatures. The valuable vulcanization characteristics obtained in the simulation will help engineers in the optimum design of processing conditions.

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Combined Effects of Hot Curing Conditions and Reaction Heat on Rubber Vulcanization Efficiency and Vulcanizate Uniformity

Cited by 9 publications

References 22 publications

Cross-Linking of Polymers: Kinetics and Transport Phenomena

Cross-Linking of Polymers: Kinetics and Transport Phenomena

Kinetic finite element model to optimize sulfur vulcanization: Application to extruded epdm weather‐strips

Kinetic Modelling and Finite Element Simulation of Natural Rubber Non-Isothermal Vulcanization

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