PVC heat stabilizer mechanism of heat

In the process, PVC thermal decomposition little change for other properties, mainly affects the color of the finished product, pvc heat stabilizers may be added to suppress the initial coloring products. When stripped of HCl mass fraction of 0.1%, PVC color began to change. Formation of conjugated double bonds according to the number of different, PVC will show different colors (yellow, orange, red, brown, black). If the aluminum stearate  thermal decomposition of PVC in the presence of oxygen, it will be colloidal carbon, a peroxide, a carbonyl group and an ester-based compound formation. However, use of the product for a long time, PVC thermal degradation of the material properties of great added pvc PVC heat stabilizer can delay the degradation time or the lower the degree of degradation of PVC.
In the course of processing PVC heat stabilizer may be added to inhibit the degradation of the PVC, thermal stabilizer pvc then play a major role are: chlorine atoms by  vegetable stearic acid displacing the unstable, the absorption of hydrogen chloride, and the addition reaction of the unsaturated sites, etc. inhibiting the degradation of PVC molecules. Ideal thermal stabilizer should have multiple functions: (1) replacement lively, unstable substituent bonded to a tertiary carbon atom such as a chlorine atom or allyl chloride, to form a stable structure; (2) and the titanium dioxide  absorption and PVC processing release of HCl, HCl elimination autocatalytic degradation; (3) and on the degradation or passivating the catalytic metal ions and other harmful impurities; (4) by means of a chemical reaction barrier forms unsaturated bond breaking the continued growth inhibiting degradation coloring; (5) is preferably a protective shielding to ultraviolet light.