Miscibility

About: Miscibility is a research topic. Over the lifetime, 5521 publications have been published within this topic receiving 133547 citations. The topic is also known as: miscible.

Functional Group Accessibility in Hydrogen-Bonded Polymer Blends. 2. Miscibility Map of 2,3-Dimethylbutadiene- stat-vinylphenol Blends with Ethylene-stat-vinyl acetate

Abstract: An experimental miscibility map for 2,3-dimethylbutadiene-stat-4-vinylphenol (DMBVPh) blends with ethylene-stat-vinyl acetate (EVA) is obtained and compared to theoretical calculations. The number of hydrogen-bonded carbonyl groups in these systems is measured by FTIR spectroscopy and some systematic trends are apparent. It is shown that the miscibility of DMBVPh/EVA blends is much more sensitive to the difference in solubility parameters than to the degree of hydrogen bonding. However, the contribution from hydrogen bonding in these mixtures is important and is significantly influenced by screening effects. A simple correlation for the dependence of the screening effect on the average spacing of functional groups in a chain is proposed and tested.

A dynamic mechanical and thermal analysis of unplasticized and plasticized poly(vinyl alcohol)/methylcellulose blends

Abstract: The miscibility of poly(vinyl alcohol) (PVA)/methylcellulose (MC) blends was investigated over the entire composition range using the dynamic mechanical analyzer (DMA) and the differential scanning calorimeter (DSC). On the basis of the glass transition temperature, determined by DMA, one could conclude that the blends exhibited some miscibility below 80 wt % of MC and a good miscibility above 80 wt % of MC. The highest depressions of the melting and crystallization temperatures of the blends compared to those of PVA, determined via DSC analysis, were observed for MC contents greater than 80 wt %. The miscibility between PVA and MC can be attributed to the hydrogen bonds formed between the two components. The DMA studies showed that water is a good plasticizer for PVA and poly(ethylene glycol) 400 (PEG 400), a good plasticizer for MC. The inclusion of both water and PEG 400 in the blends revealed a synergistic plasticizing effect, which resulted in an increased miscibility between PVA and MC over a greater range of MC compositions (>60 wt %). The elongations of PVA, MC, and their blends were found to increase with the addition of PEG 400, but the tensile strengths to decrease. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1825–1834, 2001

Hydrogen bonding in epoxy resin/poly(ε-caprolactone) blends

Abstract: Poly(ϵ-caprolactone) (PCL) of ca. 20,000 molecular weight is shown to be partially miscible with three aromatic-amine-cured epoxy resins. This conclusion is based on the depression of the epoxy Tg, the effect on physical and mechanical properties, and the observation that a large proportion (40-55%) of the PCL ester groups are involved in hydrogen bonding. This miscibility behavior is compared to PCL blends with anhydride-cured epoxy resins, which appear to have a two-phase morphology. The different miscibilities are rationalized on the basis of the existence of functional groups (e. g., hydroxyl) in amine-cured epoxies which are capable of hydrogen bonding to the PCL ester groups. Anhydride-cured epoxy resins contain fewer potential hydrogen bonding sites.