Modeling reaction kinetics of rigid polyurethane foaming process

2014

Ind. Eng. Chem. Res.

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Polyol oligomers formed from reactions of mono-, di-, and triethylene glycols with epoxidized soybean oil were synthesized and the reaction conversions were modeled. The data verified the effectiveness of a model that is based on the simultaneous solution of eight ordinary differential equations. In addition, the data demonstrated that di-and triethylene glycols produced lower viscosity oligomers than monoethylene glycol. Since the model is fundamentally based, it provides insight into the reaction mechanisms and allows for simulation of reaction conditions with reasonable extrapolation. Within the accuracy of the data, the reaction rate coefficients for all alcohol and epoxy moieties were equal, independent of the molecule to which they were attachedreaction rates varied based only on temperature and dilution of reacting moieties. The model provides an effective means to simulating concentration, viscosity, and temperature profiles including estimates of degrees of polymerization, which are dependent on a parameter related to inter versus intra-oligomerization.

“…Zhao et al, 27 Ghoreishi et al, 28 and Shen et al 29 used a similar code based on this approach to simulate urethane reactions and foam and/or gel's temperature and density profiles.…”

Section: ■ Introductionmentioning

confidence: 98%

Modeling of Toluene Sulfonic Acid Catalyzed Oxide Addition Reaction for Soy-Based Polyol

Ghoreishi

2014

Ind. Eng. Chem. Res.

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“…The impact of conformations will not be discussed in this work because it can be neglected comparing with the impact of molecular sizes and configurations. Computational results were used to improve the database of kinetic and thermodynamic parameters used in simulation studies .…”

Section: Introductionmentioning

confidence: 99%

Computational study on reaction enthalpies of urethane‐forming reactions

Zhao

Polymer Engineering & Sci

2015

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Computational calculations were performed on urethaneforming reactions using Gaussian 09 software (i.e. molecular modeling) toward the goal of providing thermodynamic parameters. Total electronic and thermal enthalpies and zero-point vibrational energies of reactants and products were computed by the software and then reaction enthalpies were calculated based on these results. The location of functional groups has the most significant impact on reaction enthalpies while molecular size, chain length and solvent effect have relatively less impact on reaction enthalpies. By comparison to new experimental studies and values reported in literature, better-informed recommendations on which values of reaction enthalpies to use for urethane foam process simulation were provided. The utility of computational chemistry results succeeded in being an enabling technology to improve foam process simulation. In turn, simulation of urethaneforming reactions is useful to bridge the gap between fundamental computational chemistry calculations and practical applications. POLYM. ENG. SCI., 55:1420-1428, 2015

“…Based on the viscosities characterizing each component, mixture rules can then be used to calculate the mixture viscosity. Figure 6 provides example profiles for degrees of polymerization and viscosity for the system of Zhao and Suppes [1]. As described in the introduction, this viscosity information is needed for more-ambitious modeling efforts intended to simulate foam formation including the estimation of physical properties for successful formation of foam as well as the collapse of unsuccessful formulations.…”

Section: Resultsmentioning

confidence: 98%

“…Zhao et al [1,2] have initiated a fundamentally-based model for urethane-forming reactions based on the simultaneous solution of over a dozen ordinary differential equations that describe reactions and energy balances. Concentration and temperature profiles can be accurately modeled, and in many applications performances can be accurately extrapolated to (predictively) simulate performances of new formulations [3,4] as a tool in new formulation development.…”

Section: Introductionmentioning

confidence: 99%

Group contribution modeling of viscosity during urethane reaction

Zhong

Journal of Polymer Engineering

2014

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Based on experimental viscosity data collected from single material and binary system mixtures, a group contribution method was introduced to estimate viscosities of a range of polyol oligomers and urethane polymers at temperatures from 25 to 150°C. Use of mixture rules then extends the estimation method to multi-component reacting systems. Mixture viscosity data were used to determine the Gibbs free energy (G) in the GrundbergNissan equation which can be used to estimate mixture viscosities with correction for some non-idealities. The resulting model is able to accurately predict mixture viscosities based on binary interaction. The goal of this work is to estimate the viscosities of urethane-forming reactions; accurate viscosity information is critical as an intermediate step to predict how successful a foam formulation would be and to ultimately estimate the final physical properties of the foam.