What is dehydrochlorination of PVC?

The thermal degradation of PVC is a complex chain dehydrochlorination that consists of an initiation process to generate an active intermediate and a series of chain reactions.

What temperature does PVC decompose?

The weight loss curve from the thermal decomposition of polyvinyl chloride is shown in Figure 1. As evident from figure, PVC having two steps weight loss curves on thermal degradation in the temperature range of 257–520°C.

How do you degrade PVC?

Thermal decomposition of PVC accompanied by hydrogen chloride secretion becomes apparent at 135 °C.In addition, hydrogen chloride which is generated in the presence of airborne oxygen, speeds up the polymer decomposition process to the point that at a temperature of 200 °C, a nearly total breakdown of PVC takes place.

Why does PVC have poor heat stability?

Polyvinyl Chloride has very poor heat stability. For this reason, additives that stabilize the material at higher temperatures are typically added to the material during production. Polyvinyl Chloride emits toxic fumes when melted or subject to a fire.

When does dehydrochlorination of PVDC polymers occur?

PVDC polymers undergo dehydrochlorination when heated above 120 °C. Initiation is believed to occur via carbon–chlorine bond scission associated with unsaturation in defect structures within the polymer chain ( Burnett et al., 1968 ).

What’s the difference between PVC and PVDC blister packs?

PVDC Polyvinylidene chloride (PVDC) can be coated onto a PVC film to obtain very high moisture and oxygen barrier properties depending on the coating weight. PVDC coated blister films are the most common and prevailing barrier films used for pharmaceutical blister packs.

What kind of catalyst is used for dechlorination of PVC?

For the catalytic degradation and dechlorination of PVC, metal oxides catalysts mainly acted as adsorbents for the evolved HCl or as inhibitors of HCl formation depending on their basicity, while zeolites and noble metal catalysts can produce lighter oil, depending the total number of acid sites and the number of accessible acidic sites.

Which is a thermal degradation method for PVC?

Thermal degradation of PVC: A review This review summarized various chemical recycling methods for PVC, such as pyrolysis, catalytic dechlorination and hydrothermal treatment, with a view to solving the problem of energy crisis and the impact of environmental degradation of PVC. Emphasis was paid on the recent progress on the pyrolysis …