THERMAL-STABILITY OF CHLORINATED PARAFFINS

Chlorinated normal paraffins are commonly used as secondary plasticizers for PVC mainly to reduce the cost of formulations. It is well known that chlorinated paraffins are susceptible to thermal degradation and many compounds have been reported as suitable stabilizers. In this report, the thermal stability of four chloroparaffins synthesized from a carefully characterized wax is compared to that of a commercial sample of PVC by DSC and thermogravimetric analysis (TGA) in an attempt to obtain more information on the nature of the degradation of these plasticizers. It has been found that for the samples containing 18 and 25 wt-% Cl and dehydrohalogenation reaction is followed by complete volatilization of the unsaturated products formed. The thermal behavior of the chloroparaffins containing 31 and 38 wt-% Cl is very similar to that of PVC.