Polyvinylchloride (with plasticizer)
PVC-P or soft PVC refers to PVC with plasticizer molecules embedded between the polymer chains with plasticizer contents of 20 to 50%. The letter P stands for plasticized. The toughness and flexibility of PVC-P varies with the kind of plasticizer. Plasticizer migration out of PVC-P after aging can result in fogging or embrittlement of the polymer. Therefore, in modern appli- cations, polymeric plasticizers, which show a slight tendency to migrate, are increasingly used. During processing, it is important not to exceed the Reazione di DecomposizioneLa decomposizione è la reazione indotta termicamente con cui una sostanza chimica genera prodotti solidi e/o gassosi. decomposition temperature of the material to avoid HCl formation.
|DSC 204 F1 Phoenix®
|Al, pierced lid
|N2 (40 ml/min)
Due to the plasticizer additive, the Temperatura di transizione vetrosaLa transizione vetrosa è una delle più importanti proprietà chimico-fisiche dei materiali amorfi e semi-cristallini, come, ad esempio, vetri, metalli (amorfi), polimeri, ingredienti farmaceutici e alimentari e definisce l’intervallo di temperatura in cui le proprietà meccaniche die materiali variano da duro e fragile a più morbido, malleabile o gommoso.glass transition temperature Tg was at -41°C in the 1st heating (blue) and -39°C in the 2nd heating (red). Evaluation of the step heights (Δcp) yielded a value of approx. 0.26 J/(g·K) in both heatings. With the help of the 1st heating (blue), the degree of gelation of the PVC can be determined*. This requires calculation of two peak areas, i.e., of Ha between T1 and process temperature T2 (representing the amount already gelled) as well as of Hb between T2 and T3 (representing the amount not yet gelled). The degree of gelation (G) in % is calculated from the ratio of Ha and the total enthalpy (Ha + Hb) multiplied by 100. In the present case, this evaluation leads to a result of 85.1%. Since the end temperature of the 1st heating was at 200°C, only one peak was visible in the 2nd heating (red) since the entire PVC was already gelled.
* H. Potente, S.M. Schultheiß, Bestimmung des Geliergrades von PVC mit der DSC, Kunststoffe 77, 1987, pages 401 - 404