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.
Authors:Stoyanka Stoeva, Dimitrinka Tsocheva, and L. Terlemezyan
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.
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.
Authors:K. Pandey, K. Debnath, P. Rajagopalan, D. Setua, and G. Mathur
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 separateTg 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.
impossible. In order to overcome this problem compatibilzer resins are used, e.g. chlorinatedpolyethylene (CPE) [ 1 , 2 ], or ∊-caprolactone grafted polymers [ 3 ]. The primary goal of this research was to investigate the compatibility limits, impact
Authors:Hengfeng Li, Kaiyuan Tan, Zeming Hao, and Guowen He
dropping the thermal stability of polymer systems. For example, among polyethylene (PE), chlorinatedpolyethylene (CPE) and poly(vinyl chloride) (PVC), the CPE generally decomposes at a lower temperature than PE during heating; however, the PVC is often
Authors:Yiqun Fang, Qingwen Wang, Xiaoyan Bai, Weihong Wang, and Paul A. Cooper
, calcium stearate (standard grade), chlorinatedpolyethylene (CPE), and rare earth heat stabilizer (KB-7) were purchased from a local chemical supplier.
The WF was dried at 105 °C for 6 h just before extrusion