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Abstract  

The thermooxidative degradation of poly(vinyl chloride) (PVC), chlorinated polyethylene (CPE) and PVC/CPE blend 50/50 was investigated by means of dynamic and isothermal thermogravimetric analysis in the flowing atmosphere of air. To estimate the thermooxidative stability of the samples the characteristics of thermogravimetric (TG) curves were used. Kinetic parameters (the apparent activation energy E and preexponential factor Z) were calculated after isoconversional method for the first stage of dynamic degradation where dehydrochlorination (DHCl) of PVC and/or CPE is the main degradation reaction. Despite the chemical resemblance, the degradation mechanisms of CPE and PVC are different, as a consequence of differences in microregularity of the corresponding polymer chains. The addition of Ca/Zn carboxylates as well as the ratio of Ca and Zn carboxylates have considerably different influence on the investigated polymers.

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Abstract  

The melting behavior of solid-state chlorinated polyethylene samples of various average molar mass has been studied by employing the differential scanning calorimetry method. Both the thermal and thermodynamic characteristics of the as-prepared chlorinated powdery polymer samples were found to be essentially different, compared to those of the melt-crystallized ones. The changes in the corresponding values depended mainly on the content of the comonomer units such as chloromethylene and dichloromethylene groups and their distribution along the polymer chains. Therefore, it can be assumed that the order of the polymer crystals arrangement is disturbed in the course of both the chlorination process and the subsequent melt crystallization.

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Summary A mathematical description of the dependence of softening temperature of poly(vinyl chloride) blends with solid-state chlorinated polyethylene on the degree of chlorination of polyethylene and the amount of chlorinated polyethylene were studied. A method for calculation the coefficients in the corresponding empiric equation was suggested. The latter can successfully be used for practical purposes in preparation of various composition with selected softening temperature.

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Thermal analysis on influence of compatibilizing agents

Effect of vulcanization of incompatible elastomer blend

Journal of Thermal Analysis and Calorimetry
Authors: K. Pandey, K. Debnath, P. Rajagopalan, D. Setua, and G. Mathur

Abstract  

Studies have been made on differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and dynamic mechanical analysis (DMA) of binary blends of isobutylene-isoprene (IIR) copolymer and polychloroprene (CR) elastomers. Blends of IIR and CR are incompatible and showed separateT g peaks in DSC curves similar to Tanδ peaks. However, addition of chlorinated polyethylene (CM) elastomer, as compatibilizer, imparts miscibility between IIR and CR which could be judged both through DSC as well as by dynamic loss measurements (Loss modulusE″ and Tanδ). The storage modulus (E′) showed variation of stiffness due to structural changes associated with the addition of compatibilizer. TG plots for these blends showed improvement of thermal stability both by addition of a suitable compatibilizer as well as due to formation of crosslinked structures associated with the vulcanization of the blends by standard curative package.

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impossible. In order to overcome this problem compatibilzer resins are used, e.g. chlorinated polyethylene (CPE) [ 1 , 2 ], or ∊-caprolactone grafted polymers [ 3 ]. The primary goal of this research was to investigate the compatibility limits, impact

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dropping the thermal stability of polymer systems. For example, among polyethylene (PE), chlorinated polyethylene (CPE) and poly(vinyl chloride) (PVC), the CPE generally decomposes at a lower temperature than PE during heating; however, the PVC is often

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– 233 10.1007/s10973-005-7189-3 . 18. Stoeva , S , Tsocheva , D , Terlemezyan , L . Thermal behavior and characterization of solid-state chlorinated polyethylenes . J Therm Anal

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(vinyl chloride)/chlorinated polyethylene blends investigated by thermal analysis methods . Polym Degrad Stab . 2004 ; 84 : 23 – 30 . 10.1016/j.polymdegradstab.2003.08.012 . 7. Moly , KA

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, calcium stearate (standard grade), chlorinated polyethylene (CPE), and rare earth heat stabilizer (KB-7) were purchased from a local chemical supplier. Compounding The WF was dried at 105 °C for 6 h just before extrusion

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