A DSC investigation on the stabilizer distribution in PVC blends

Abstract

The distribution of a liquid organotin stabilizer between the phases of heterogeneous poly(viny1 chloride) (PVC) blends has been studied by differential scanning calorimetry (DSC). This method can be used even at low stabilizer concentrations. At concentrations > 1 wt.4'0 the stabilizer can be detected in both phases of a PVCISAN (poly(viny1 chloride)/poly(styrene-co-acrylonitrile)) blend. At lower concentrations no stabilizer could be found in the SAN phase. Determination of the induction period of thermal degradation at 180°C under nitrogen atmosphere showed no loss of thermal stability for blends containing the stabilizer partly in the SAN phase. Kinetic measurements with the DSC indicate a migration of the stabilizer out of the SAN phase. PVC/PMA (poly(viny1 chloride)/poly(methyl acrylate)) blends showed no solubility of the stabilizer in the soft PMA phase. ZUSAMMENFASSUNG:Es wurde die Verteilung eines flussigen Organozinnstabilisators zwischen den Phasen zweiphasiger Blends aus PVC/SAN sowie PVC/PMA mittels DSC untersucht. Die angewandte Methode erwies sich als geeignet, die Verteilung auch in niedrigen Konzentrationsbereichen zu messen. In PVC/SAN-Blends befindet sich der Stabilisator bei Konzentrationen > 1 Gew.-qo in beiden Phasen, bei niedrigeren Konzentrationen nur im PVC. Messungen der Induktionszeiten des thermischen Abbaus bei 180 "C unter Stickstoff zeigen keine Verschlechterung der stabilisierenden Eigenschaften fur die Blends, bei denen ein Teil des Stabilisators in der SAN-Phase vorlag. Kinetische Messungen mit der DSC-Methode sprechen fur eine Migration des Stabilisators aus dem SAN. In PVC/PMA-Blends wurde dagegen eine vollstandige Unlaslichkeit des Stabilisators in der weichen Polyacrylatphase nachgewiesen.

A recycling assessment of PVC bottles by means of heat impact evaluation on its reprocessing

“…However, a weight loss about 0.3%, observed under similar severe experimental heating conditions, implies the depletion of some ingredients, to a certain extent, acting as plasticizer. 28 The cooling section of the DSC curves indicates the same transition of about 80ЊC.…”

“…However, neither the samples after heat treatment at 180ЊC on heating region nor any of the samples on cooling region of DSC curves showed such a peak. Braun et al 28 observed that the glass transition temperature of PVC samples with heat stabilizers attained after consecutive annealing up to 200ЊC at a value of the PVC samples without stabilizer. They attributed this behavior to the consumption of stabilizer in the heating process.…”

Polymer blends based on poly(vinyl chloride) and biodegradable aliphatic–aromatic copolyester

“…The decrease in T g of the blends was not influenced only by AAC. It was proven that T g of PVC decreased in the presence of other miscible additives, such as thermal stabilizers 17. With regard to the neat polymer, AAC in the blends was no longer partially crystalline but was completely amorphous, and we supposed that intermixing of the polymers at a molecular level occurred.…”