The Formation and Thermal Stability of Polyvinyl Chloride

Chamy, Peter G (1976) The Formation and Thermal Stability of Polyvinyl Chloride. PhD thesis, University of Glasgow.

Abstract

The thermal stability of Polyvinyl chloride (PVC) was studied. Three phases of degradation were investigated, 1. Dehydrochlorination 2. Discolouration 3. Cross linking The effect of the polymerisation reaction on the final stability of the polymer was also studied, by varying, 1. The type and concentration of initiator 2. The polymerisation temperature 3. The percent polymer conversion 4. The method of polymerisation The polymers thus formed were characterised and then degraded. The results indicate an increase in stability with decrease in polymerisation temperature. The change in initiator type and concentration altered the kinetics of the polymerisation reaction and hence the properties of the polymer formed. Polymers obtained at different conversions exhibited a stability 'Maxima' around 40-60% conversion. Some of the polymers prepared in solution showed marked increase in stability and those prepared by photo irradiation showed a different mechanism of degradation. Two commercial polymers were also studied for comparison. The activation energy for the dehydrochlorination of PVC in solution was found to be 21 k cal/mole and the reaction showed 3 distinct stages. The discolouration, or the polyene formation in PVC due to thermal degradation was characterised into two different reactions with different activation energies. The changes in molecular weight during the degradation is reported. There exists an inverse relationship between the molecular weight of the polymer and the rate of dehydrochlorination.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Polymer chemistry, Thermodynamics, Physical chemistry
• Date of Award: 1976
• Depositing User: Enlighten Team
• Unique ID: glathesis:1976-78729
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 30 Jan 2020 14:58
• Last Modified: 30 Jan 2020 14:58
• URI: https://theses.gla.ac.uk/id/eprint/78729