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polymer blends, those containing poly(vinylchloride) (PVC), one of the most common commercial thermoplastics, are among the most important from both a scientific and a commercial point of view. PVC is, therefore, often blended with other polymers [ 6 – 9

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Abstract  

Thermogravimetric analysis (TG) was used in this work to study the degradation kinetics of industrial PVC plastisols. In order to model the pyrolitic degradation of plastisols in nitrogen, a kinetic model based on phenomenological considerations was developed. Two different processes were observed during the first degradation stage. The model parameters, such as activation energies and pseudo orders of reaction, were calculated using a non-linear regression analysis. The model developed was able to describe the degradation behaviour both in isothermal and in dynamic modes. The results of such analysis were applied to obtain long-term data from short-term experiments as an engineering approach to evaluate the thermal resistance of plastisols.

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Journal of Thermal Analysis and Calorimetry
Authors: M. Beneš, V. Pla?ek, G. Matuschek, A. A. Kettrup, K. Györyová, W. D. Emmerich, and V. Balek

Summary  

Thermal behavior of commercial PVC cable insulation both before and after extraction of plasticizers, fillers and other agents were tested by TG/DTG and DSC during heating in the range 20-800C in air. The ultrasound enhanced hexane extraction and dissolution in THF with subsequent precipitation of PVC were used to prepare 'extracted' and 'precipitated' samples. The total mass loss measured for the 'non-treated', 'extracted' and 'precipitated' PVC samples was 71.6, 66.6 and 97%, respectively. In the temperature range 200-340C the release of dioctylphthalate, HCl and CO2was observed by simultaneous TG/FTIR. From TG results measured at different heating rates (1.5, 5, 10, 15 K min-1) in the range 200-340C the non-isothermal kinetics of the PVC samples degradation was determined. Activation energy values of the thermal degradation processes calculated by ASTM E 698 method, for 'non-treated', 'extracted' and 'precipitated' PVC samples were 174.617 kJ min-1, 192.819 kJ min-1, 217.120 kJ min-1, respectively. These kinetic parameters were used for the lifetime simulation of the materials.

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Abstract  

Thermogravimetry (TG/DTG) coupled with evolved gas analysis (MS detection) of volatiles was used to characterize the thermal behavior of commercial PVC cable insulation material during heating in the range 20-800C in air and nitrogen, respectively. In addition, simultaneous TG/FTIR was used to elucidate chemical processes that caused the thermal degradation of the sample. A good agreement between results of the methods was found. The thermal degradation of the sample took place in three temperature ranges, namely 200-340, 360-530 and 530-770C. The degradation of PVC backbone started in the range 200-340C accompanied by the release of HCl, H2O, CO2 and benzene. The non-isothermal kinetics of thermal degradation of the PVC cable insulation in the temperature range 200-340C was determined from TG results measured at heating rates of 1.5, 5, 10, 15 and 20 K min-1 in nitrogen and air, respectively. The activation energy values of the thermal degradation process in the range 200-340C of the PVC cable insulation sample were determined from TG results by ASTM method.

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Introduction For many years, poly(vinyl chloride) (PVC) has been one of the most important technical polymers that have wide applicability specially in medicine due to its easy modification by various additives, such as

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Introduction The poly-vinyl-chloride (PVC) is a widely used commodity polymer because of its excellent properties; such as high stiffness, good transparency, low flammability and favourable price. PVC is recyclable, but

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Abstract  

By dissolution of PVC and polyaniline in dimethylformamide, a series of blends PVC-polyaniline were produced which were studied by scanning electron microscopy and thermogravimetry. Special attention is focused on the kinetic study of the thermal degradation steps by using non-isothermal thermogravimetric data. The results show that the thermal stability of the synthesized blend is decreased as the total amount of polyaniline is enhanced. Furthermore, the Brřnsted acid doped blend is more stable than the corresponding undoped one. PVC and the PVC-polyaniline blends exhibit two mass loss steps which activation energy values are in the range from 176 to 283 kJ mol-1 and 306 to 322 kJ mol-1, respectively.

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Abstract  

The process of thermal degradation of poly(vinyl chloride)/poly(methyl methacrylate-butadiene-styrene) (PVC/MBS) blends was investigated by means of isothermal thermogravimetry in nitrogen. The total mass loss was determined after 120 min. The kinetic parameters of the degradation process were determined by applying two kinetic models: the model which assumes autocatalytic degradation (Prout-Tompkins) and the model of two-dimensional diffusion. It was established that the thermal degradation at lower degrees of conversion (α<0.20) was well described by the former model, but the latter model was applicable at higher degrees of conversion. The thermal stability of blends at a certain temperature of isothermal degradation depends on the blend composition and the shell/core ratio in MBS, and on the adhesion in the boundary layer in PVC/MBS blends.

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Abstract  

The thermo non-oxidative degradation of PVC and the effects of alkaline earth metal (Be, Mg, Ca, Ba) stearates were studied by thermogravimetry in the temperature range 150 to 500°C. The alkaline earth metal stearates were observed effectively reduce the dehydrochlorination of PVC. The synergistic effects of combinations of these salts with lead stearate were also studied and are discussed. Kinetic parameters such as the activation energy, order of reaction and Arrhenius factor were calculated by the Coats and Horowitz methods. The results showed that these metal stearates increase the activation energy required for the dehydrochlorination of PVC.

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