Naslov
Kinetics of thermooxidative degladation of poly(vinyl chloride)/chlorinated polyethylene blends stabilized with Ca/Zn stearate

Autori
Stipanelov Vrandečić, Nataša ; Klarić, Ivka ; Kovačić, Tonka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Current and Future Trends in Polymeroc Materials / Raab, Miroslav - Prag : Institute of Macromolecular Chemistry Academy of Science of the Czech Republic, 2005

Skup
23rd Discussion Conference Current and Future Trends in Polymeric Materials

Mjesto i datum
Prag, Češka Republika, 26.07.2005. - 30.07.2005

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
PVC/CPE blends; thermooxidative degradation

Sažetak
Poly(vinyl chloride)(PVC) has a wide applicability due to its easy modification by various additives. Chlorinated polyethylene (CPE) with chlorine content 30 - 40 mass% is an impact modifier of PVC. Adding of heat stabilizers is necessary to prevent the decomposition of PVC by heat and share during processing. Ca/Zn stabilizers are one group of commercially available PVC heat stabilizers, interesting because of their physiological harmlessness. Since PVC/CPE blends are in contact with heat and air either during processing or application, a good knowledge of thermooxidative stability of blend components is very important. The thermooxidative degradation of PVC/CPE blends of different composition stabilized with 2 mass% of Ca/Zn stearate was investigated by means of dynamic thermogravimetry in flowing atmosphere of air in the temperature range 50 - 650 oC. Kinetic analysis was applied to the first degradation step (up to 400 oC) were the main degradation processes were dehydrochlorination of the PVC and CPE. Kinetic parameters, apparent activation energy and preexponential factor, were calculated after differential isoconversional Friedman equation. The compensation plots ln Z vs. E with correlation coefficient 0.989 indicates that PVC and CPE in the blends with addition of Ca/Zn stearate have similar degradation mechanism, opposite of corresponding mechanisms of nonstabilised PVC and CPE[1]. According to our previous work [2], this can be explained by different influence of Ca/Zn stearate on polymers in the blend, despite of their chemical resemblance. Ca/Zn stearate is stabilizer for PVC, but not for CPE. From the Arrhenius plots, calculated from the kinetic parameter, it could be concluded that all degradation reactions take place with approximately same rate at temperature of 590 K. [1] N. Stipanelov Vrandečić, I. Klarić and T.Kovačić, Polym Degrad Stab, 84 (2004) 31-39 [2] N. Stipanelov Vrandečić, I. Klarić and T.Kovačić, J. Therm. Anal. Cal., 74 (2003) 171-180

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

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