Stability analysis, thermal molding

The polymers and monomers were characterized for chemical composition and purity (NMR, FT-IR, elemental analysis), thermal analysis (DSC), melt rheology (melt stability and viscosity), molecular weight (inherent viscosity), crystallinity (XRD). Baseline and in-vitro mechanical properties (Instron stress/strain) were determined on molded and extruded samples. 

This hypothesis has been confirmed by the greatly improved thermal stability of PVC as a result of the formation of a graft copolymer of d -l,4-polybutadiene onto poly (vinyl chloride). The improved thermal stability is demonstrated by the almost total absence of discoloration on molding the graft copolymer into a film at 200°C in air, the reduced rate of dehydrochlorination on heating in an inert atmosphere at 180°C, and higher onset and peak temperatures for hydrogen chloride evolution as determined by differential thermal analysis. 

The excellent thermal stability of polysulfone is verified by thermal gravimetric analysis which shows that UDEL Polysulfone is stable to air up to 450°C (840°F). The excellent thermal stability coupled with excellent oxidation resistance of polysulfones provides excellent melt stability for molding and extrusion. 

---