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Investigation of molding powder production on two different-sized Buss kneaders is presented. The storage moduli, energy consumption, and the pressure profiles were observed at different material loads, screw revolutions, and material... more
Investigation of molding powder production on two different-sized Buss kneaders is presented. The storage moduli, energy consumption, and the pressure profiles were observed at different material loads, screw revolutions, and material fills. Experimentally measured data were compared to calculated ones using previously developed flow model and two parameters; storage moduli and complex viscosity were calculated for different process conditions. Additionally, optimal process conditions and scale-up procedure for two different-sized Buss kneaders were proposed. The results may contribute to better understanding of kneading processes in industrial plants with respect to operation costs, energy consumption and environmental care.
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The free-radical polymerization kinetics of diethylene glycol bisallyl carbonate in bulk were investigated with Fourier transform infrared and Fourier transform Raman techniques in a wide temperature range of 50–140°C with four different... more
The free-radical polymerization kinetics of diethylene glycol bisallyl carbonate in bulk were investigated with Fourier transform infrared and Fourier transform Raman techniques in a wide temperature range of 50–140°C with four different peroxide initiators. In addition, the ratios of the degradative kinetic rate constant to the propagation rate constant under different reaction conditions were obtained from molecular weight measurements under various reaction conditions. The ratio of the chemically controlled termination and propagation rate constants of the polymerization system were obtained with the initial rates of polymerization and the number-average molecular weight data, which were between 8.22 × 10−5 and 1.47 × 10−3 L mol−1 s−1. The initiator efficiencies were evaluated with special experiments at low initiator concentrations with the theory of dead-end polymerization. The computed conversions from the developed kinetic model were in good agreement with the conversion and molecular weight measured data. The values of the diffusion-controlled propagation and termination rate constants, with clear and physical meaning, were the only two parameters obtained from the developed kinetic model fitting the measured conversion points. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 345–357, 2005
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Free radical polymerization kinetics of diallyl terephthalate in bulk was investigated in a wide temperature range from 50°C to 150°C with four different peroxide initiators. Conversion points were measured using Fourier Transform... more
Free radical polymerization kinetics of diallyl terephthalate in bulk was investigated in a wide temperature range from 50°C to 150°C with four different peroxide initiators. Conversion points were measured using Fourier Transform Infrared (FTIR) measurements. The initiator efficiencies and the initiator decomposition rate constants were evaluated from special experiments, applying the theory of dead end polymerization. In addition, the ratios between the degradative and the effective kinetic rate constants to propagation rate constants were obtained from molecular weight measurements at various initiator concentrations. The ratio of chemically controlled termination and propagation rate constant k/ktc of the polymerization system was obtained using the initial rates of polymerization and the number average molecular weight data between 0.25 · 10−3 and 15.7 · 10−3 L mol−1 s−1. The glass transition temperature of the polymer, 191°C, was measured by the Alternating Differential Scanning Calorimetry (ADSC) technique. Computed conversions from the developed kinetic model were in good agreement with the conversion and molecular weight measured data. The values of diffusion controlled propagation and termination rate constants ktd0 and kpd0 with clear and physical meaning were the only two parameters obtained from the developed kinetic model fitting. Polym. Eng. Sci. 44:2005–2018, 2004. © 2004 Society of Plastics Engineers.
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Attenuated total reflection infrared spectroscopy (ATR-FTIR) was used to measure diffusion of diallyl terephthalate monomer (DAT) into a polyDAT film. The assembly, consisting of an ATR crystal, polymer film and a monomer, was heated to a... more
Attenuated total reflection infrared spectroscopy (ATR-FTIR) was used to measure diffusion of diallyl terephthalate monomer (DAT) into a polyDAT film. The assembly, consisting of an ATR crystal, polymer film and a monomer, was heated to a desirable interdiffusion temperature, the spectra thus obtained were deconvoluted and the diffusion coefficient of DAT monomer into polymer was calculated by least square regression technique at various temperatures from 21 °C to 50 °C and, various film thicknesses from 60 μm to 180 μm.
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A mathematical model describing free radical polymerization of diallyl terephthalate in a bulk, which exhibits strong diffusion limitations from the beginning of the reaction, was developed. The diffusion limitations are viewed as an... more
A mathematical model describing free radical polymerization of diallyl terephthalate in a bulk, which exhibits strong diffusion limitations from the beginning of the reaction, was developed. The diffusion limitations are viewed as an integral part of the chain propagation and termination processes. The influence of temperature and initiator loading on the reaction process was investigated. Initiator decomposition rate constants were obtained from special experiments, by using the dead end theory. The ratios of degradative and the effective chain transfer rate coefficients to propagation rate coefficients were in range between 0.01 to 0.06 for k Deg /k p and between 0.001 to 0.008 for k Eff /k D . Ratios were evaluated from GPC molar mass measurements. The kinetic parameters were estimated by fitting the experimentally obtained conversion measured by FTIR for various initiators in temperature range from 50 °C to 150 °C by using peroxide initiators CHPC and DCPO. Activation energies e...
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In the present study a comparison was made of two most frequently used algorithms for calculation of the apparent rate constant in the kinetic modelling of bulk cross-linking diallyl terephthalate (DAT) polymerization with four different... more
In the present study a comparison was made of two most frequently used algorithms for calculation of the apparent rate constant in the kinetic modelling of bulk cross-linking diallyl terephthalate (DAT) polymerization with four different peroxide initiators, bis(4
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A quick and simple approach for reactor—emergency relief system design—for runaway chemical reactions is presented. A cookbook for system sizing with all main characteristic dimensions and parameters is shown on one realistic example from... more
A quick and simple approach for reactor—emergency relief system design—for runaway chemical reactions is presented. A cookbook for system sizing with all main characteristic dimensions and parameters is shown on one realistic example from process industry. System design was done based on existing theories, standards, and correlations obtained from the literature, which were implemented for presented case. A simple and effective method for emergency relief system is shown, which may serve as an example for similar systems design. Obtained results may contribute to better understanding of blow down system frequently used in industrial plants, for increasing safety, decreasing explosion damage, and alleviating the ecological problems together with environmental pollution in case of industrial accidents.
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Free radical polymerization kinetics of diallyl terephthalate (DAT) in solution was investigated with two different peroxide initiators: dicyclohexyl peroxydicarbonate (CHPC) and benzoyl peroxide (BPO) in temperature range from 50°C to... more
Free radical polymerization kinetics of diallyl terephthalate (DAT) in solution was investigated with two different peroxide initiators: dicyclohexyl peroxydicarbonate (CHPC) and benzoyl peroxide (BPO) in temperature range from 50°C to 110°C, where ortho-xylene was used as a solvent. Conversion points were measured using Fourier Transform Infrared (FTIR) measurements. Previously developed kinetic model for bulk DAT polymerization, was extended to solution DAT polymerization. The ratio of solvent chain - transfer rate constants to propagation rate constants of the polymerization system were found between 1.25 10-4 to 1.68 10-4 for various reaction conditions. They were obtained using the calculated initial polymerization rates and the number average molecular weight measurements made by GPC. The effect of different solvent fractions and initiator concentrations on the diffusion limitations were investigated. Only two kinetic parameters, kpd0 and ktd0 were obtained by fitting the kine...