ABSTRACT:The thermal behavior and morphology of multicomponent blends based on PA6, polyamide 6 (PA6)/styrene-acrylonitirle copolymer (SAN), PA6/acrylonitrilebutadiene-styrene terpolymer (ABS), and their compatibilized blends with styreneacrylonitrile-maleic anhydride copolymer (SANMA) were studied using DSC and SEM. The blends were prepared in a twin-screw extruder under similar processing conditions, keeping the PA6 content fixed at 50 wt %. It was found that, in all the blends, the second component had a nucleating effect and improved the overall degree and rate of crystallization of PA6, whereas addition of a compatibilizer slightly diminished these effects and resulted in significant changes in the blend morphology. The nucleating effect and consequent changes in the crystallization behavior was attributed to the presence of SAN, which is a common component in all the blends. The T g of PA6 in the blends with a cocontinuous morphology, due to the connectivity between the phases, is higher than in the blends with a disperse-type morphology. The compatibilized blends have a lower crystallization rate and nucleation ability with a cocontinuous morphology, whereas the uncompatibilized blends have a higher crystallization rate with a higher nucleation ability and a disperse and/or a coarse cocontinuous morphology.
The (trimethylsi1oxy)benzoyl chlorides 1 -7 are easily to obtain under mild conditions from silylated hydroxybenzoic acids by means of thionyl chloride. Whereas these acid chlorides are stable at room temperature, they undergo condensation polymerization at temperatures above 100°C. Reactions with various nucleophils, such as thioalcohols, phenols, amines, N,O-bis(sily1ated) amino acids and N-silylated lactams were investigated. With hexamethyldisilazane and thionyl chloride the (trimethylsi1oxy)benzonitriles 21, 22 are accessible, and by means of trimethylsilyl azide the (trimethylsi1oxy)phenyl isocyanates 23 -25 were obtained. Conversion with phenyl carbazate and subsequent silylation lead to the 2-(trirnethylsiloxy)phenyl-l,3,4-oxadiazol-5-ones 27a -c.
Frau Professor Dr. E. Husemann zum 65. Geburtstag gewidmet (Eingangsdatum: 17. September 1973) ZUSAMMENFASSUNG: Theoretische Betrachtungen zeigen, da8 man bei Pfropfcopolymeren durch Lichtstreuungsmessungen in Losung au8er den Molekulargewichten und Tragheitsradien der Pfropfaste auch die Unvertraglichkeit der Pfropfaste mit der Pfropfunterlage ermitteln kann, wenn das verwendete Losungsmittel isorefraktiv mit der Pfropfunterlage ist, und man den Gewichtsanteil an Pfropfasten kennt. Die neue Methode der Unvertraglichkeitsbestimmung aus anomalen Zimm-Diagrammen wird an Mischungen aus Polystyrol und einem chemisch einheitlichen statistischen Athylen/Vinylacetat-Copolymeren geschildert und auf Fraktionen von entsprechenden Pfropfcopolymeren angewandt. Die Ergebnisse der Lichtstreuung werden mit den Ergebnissen der Phasentrennung aus Triibungspunktmessungen verglichen. * Vorgetragen auf dem Makromolekularen Kolloquium in Freiburg i. Br., Marz 1973.
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