Glass Transition of PVC and Chlorinated PVC - METTLER TOLEDO

Glass Transition of PVC and Chlorinated PVC

Sample

  1. PVD powder with 56.6% Cl, 8.792 mg
  2. Chlorinated PVC (PVCC) with 60.8% Cl, 14.903 mg
  3. Chlorinated PVC (PVCC) with 66.4% Cl, 10.804 mg

 

Conditions

Measuring cell: DSC821e  with air cooling and automatic sample changer

Pan: Aluminum standard 40 μl, hermetically sealed

Sample preparation: Samples weighed in without pressing before sealing

DSC measurement: Heating from 35 to 150°C at 10 K/min to eliminate thermal history, quench-cooling in the sample changer. Second heating run 35 to 150 °C

Atmosphere: Static Air


 

Interpretation

The three measurements show the effect of the chlorine concentration on the glass transition. Higher concentrations of chlorine decrease the molecular mobility. As a result of this, the glass transition shifts to higher temperatures. The broadening of the glass transition with increasing chlorine content is particularly noticeable. The reason for this is the relatively large degree of inhomogeneity of the chlorine distribution. In chlorination, a hydrogen atom is replaced by a chlorine atom. This does not change the number of degrees of freedom of a monomer unit. The step height (Δcp) with respect to the molar mass therefore remains unaffected by chlorination. The decrease in the step height with increasing chlorination, which is apparent in the figure, is therefore due to the increase in size of the molar mass. 


Glass Transition of PVC and Chlorinated PVC | Thermal Analysis Handbook No.HB223  | Application published in METTLER TOLEDO TA Application Handbook Thermoplastics