Showing papers on "Miscibility published in 1977"

Miscibility of poly(vinyl chloride) with ethylene‐ethyl acrylate‐carbon monoxide terpolyrners

Abstract: Ethylene/ethyl acrylate/carbon monoxide ter polymers (E/ EA/CO) can exhibit a very high degree of miscibility with poly(vinyl chloride) as determined from dynamic mechanical measurements. The blends yield transparent films and show a large amorphous phase which exhibits only one major glass transition. However, some crystallinity can be detected and has been measured by differential, scanning calorimetry. Residual crystallinity is at least partially due to the somewhat non-uniform nature of the terpolymerization. The acrylate monomer exhibits faster polymerization rates than the other two constituents. By contrast, ethylene/ethyl acrylat copolymers are not miscible with poly(vinyl chloride). The addition of carbon monoxide to the termpolymer structure is believed to yield miscibility with poly(vinyl chloride) via specific interaction of the ketone carbonyl of the terpolymer (proton acceptor) and the tertiary hydrogen of poly(vinyl chloride) (proton donor). This specific interaction allows for a broad range of terpolymer compositions which retain miscibility with polyvinyl chloride. Similar results are also observed with ethylene/vinyl acetate/carbon monoxide (E/VA/CO) as well as ethylene/2-ethylhexyl acrylate/carbon monoxide termpojymers. The vinyl acetate terpolymers (and their blends) display a lower degree of crystallinity than the E/EA/ CO. This is consistent with the more uniform nature of the E/VAJCO terpolymerization.

Miscibility Studies on Heterogeneous Polymer Blends by Radioluminescence Spectroscopy and Particle Coarsening Measurements

Abstract: Interest in the subject of polymer miscibility has been stimulated by the investigation and common use by industry of heterogeneous polymer systems. Particularly, in recent years we have seen the development of materials, such as ABS, high-impact polystyrene, block copolymers, thermoplastic elastomer blends (TPR, etc.), and many more, which owe their unique properties to a certain critical degree of immiscibility of the polymeric constituents. This subtle difference in miscibility contributes to the formation of morphological features in the above-mentioned materials. More importantly, it governs the adhesion between the domains of the phase-separated polymeric composite. The latter property provides for stress transfer across the interface and thus is needed for the attainment of physical strength. Thus the questions posed by researchers are not so much concerned with whether two polymers are fully miscible on a molecular scale, a rare event indeed, but rather in the degree of miscibility of the...

Significant structure theory applied to phase separation.

Abstract: The significant structure theory of liquids has been applied to the partially miscible system of the O3-O2 mixture, which exhibits partial miscibility in the temperature range from -195.5°C to -179.9°C. The thermodynamic condition for phase separation is given by the following inequality: [Formula: see text] A partition function for the binary liquid mixture is developed using significant liquid structure theory. Here Xi is the mole fraction of either of the two components. We obtain the coexistence curve of the O3-O2 system by varying the mole fractions of the components to find the temperature at which the two liquids separate. The agreement between theory and experiment is satisfactory.