Summary Liquid natural rubber of two different molecular masses, viz.,
and 9500, each with epoxidation of 20 and 50 mol % (L-ELNR-20, L-ELNR-50, and H-ELNR-20, H-ELNR-50) were prepared and blended
with polyvinyl chloride (PVC). Miscibility of these blend systems was studied with special reference to blend ratio, mol %
of epoxidation and effect of molecular mass of the liquid rubber by various techniques such as stress – strain measurement,
SEM studies and DSC analysis. It was observed that PVC/L-ELNR-50 and PVC/H-ELNR-50 systems were homogenous and miscible compared
to PVC/L-ELNR-20 and PVC/H-ELNR-20 blends and the maximum modification in properties was found for the former systems. Results
of blends with 20 mol % epoxidised liquid rubber showed that the components are only partially miscible and hence they are
heterogeneous systems. Miscibility achieved with an increase in mol per cent epoxidation of the liquid rubber is explained
on the basis of the higher polar interaction between the blend components. Analysis of the blends also revealed that the lower
molecular mass epoxidised rubber is aiding better property modifications than the higher molecular mass rubber. This is explained
by the fact that rubber with lower chain length provides greater penetration into the PVC interstices enabling better solubilisation
of the PVC segments. 相似文献
Isotactic polypropylene/poly(cis-butadiene) rubber (iPP/PcBR) blends were prepared by melt mixing. Phase morphology of the blends was investigated by scanning electronic microscopy (SEM). It was found that the dispersed phase spread in continuous phase in a form of spherical particles. The size of the dispersed phase increased as its content increased. The phase-inversion region was the composition of 50/50 and 40/60 vol% in the blends. In the phase-inversion region, a double continuous phase was formed. The glass transition temperatures (Tg) of iPP, PcBR and blends were analyzed by dynamic mechanical analysis (DMA). The blend compositions exhibited two distinct glass transition temperatures corresponding to the iPP-rich and PcBR-rich phases, respectively. The approach of these two peaks with increasing PcBR content indicated partial miscibility between the iPP and PcBR, which was verified by the equilibrium melting point depression of blends. 相似文献
This study examined the miscibility, mechanical and thermal properties of melt-mixed blends of PTT(poly(trimethylene terephthalate)) with PP(isotatic polypropylene). DMA and SEM results indicated that the PTT/PP blends are immiscible. Revealed from TGA analyses, the blends with a higher PP content showed a higher degradation temperature. A complex melting behavior was observed for the blends. The isothermal crystallization kinetics of the blends was analyzed from 200°C to 210°C using the Avrami equation. The WAXD results showed that the crystal structure of PTT remained unchanged in the blends. Nevertheless, the PP rich blends possessed lower tensile strength and higher elongation at break. 相似文献
Summary: The miscibility and crystallization behaviors of polyamide 6 (PA 6)/polytetrafluoroethylene (PTFE) blends, prepared via reactive extrusion, are systematically investigated by means of wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). WAXD measurements show that no co‐crystallization occurred between two components, while DSC and DMTA measurements suggest that a certain degree of miscibility between them might exist due to the formation of some copolymers during the reactive extrusion.
DMTA curves for the pure PA 6 sample and PA 6/PTFE blends with various compositions. 相似文献