Co-continuous structures can be regarded as the coexistence of at least two continuous structures within the same volume. Blends with co-continuous structures may combine the properties of both components in a favorable way, for example, mechanical moduli. This review article deals with the identification, characterization, and properties of co-continuous structures as well as with the development of co-continuous structures during the melt blending process. Co-continuous structures usually can be formed within a composition region about the phase inversion composition, which mainly depends on the viscosity ratio. On the other hand, co-continuous structures can be found independent of composition as intermediate stages during the initial state of morphology development and during phase inversion process in blends in which the component finally forming the dispersed phase forms the matrix in early mixing states. In addition, even at low volume fractions of one component, stable co-continuous morph...

Formation of Co-continuous Structures in Melt-Mixed Immiscible Polymer Blends

Controlled preparation and properties of porous poly(l-lactide) obtained from a co-continuous blend of two biodegradable polymers

Phase behavior and its viscoelastic response of polylactide/poly(ε-caprolactone) blend

Polymer blends of poly(vinylphenol) (PVPh) with poly(vinylpyrrolidone) (PVP) were prepared by solution casting from the N,N-dimethylformamide (DMF) solution. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and solid-state nuclear magnetic resonance (NMR) were used to investigate the hydrogen bonding and miscibility behavior of the blend. This PVPh/PVP blend system has a single glass transition temperature over the entire composition range, indicating that this blend is able to form a miscible phase due to the formation of inter-hydrogen bonding between the hydroxyl of PVPh and the carbonyl of PVP. Furthermore, FTIR and solid-state NMR were used to study the hydrogen-bonding interaction between the PVPh hydroxyl group and the PVP carbonyl group at various compositions. According to the Painter−Coleman association model (PCAM), the interassociation constant for the PVPh/PVP blend is significantly higher than the self-association constant of PVPh, revealing that the t...

https://ir.nctu.edu.tw:443/bitstream/11536/29502/1/000169844100024.pdf

Studies of Miscibility Behavior and Hydrogen Bonding in Blends of Poly(vinylphenol) and Poly(vinylpyrrolidone)

Block copolymer compatibilization of cocontinuous polymer blends

The morphological stability of polystyrene high-density polyethylene (PS/PE) blend is investigated in the region of dual-phase continuity. The effect of the addition of a triblock SEBS copolymer to the blends on the stability of these morphologies, is examined. The results show that the morphology of the unmodified blends changes from co-continuous to droplet matrix for PS-rich blends whereas the morphology of a 50/50 blend maintains continuity but coarsened significantly upon annealing at 200°C. In the presence of the copolymer, these morphologies are much more stable. Selective solvent extraction of polystyrene in di-ethyl ether reveals that the level of PS continuity in the 50/50 blend is higher for the unmodified system than for the modified one. Upon annealing, the level of PS continuity significantly increases for the unmodified 50/50 PS/PE blend. The effect of the copolymer content in the blend on the interfacial tension between the two components is also investigated using the breaking thread method. The interfacial tension is found to be reduced from 5.6 to 1.1 mN/m by the addition of 20 parts of the copolymer to the blend. © 1997 John Wiley & Sons, Inc.

Morphological stability, interfacial tension, and dual-phase continuity in polystyrene-polyethylene blends

Phase inversion and dual-phase continuity in polymer blends: theoretical predictions and experimental results

The linear viscoelastic properties of polystyrene polyethylene (PS/PE) blends have been investigated in the molten state. For concentrations of the dispersed phase equal to 30 vol %, the blends exhibited a droplet-matrix morphology with a volume-average diameter of 5.5 μm for a 70/30 PS/PE blend at 200 °C and 14.7 μm for a 30/70 PS/PE blend at 230 °C. Enhanced elasticity (G') for both blends, in the terminal zone, compared to the modulus of the matrix (PS and PE, respectively) was observed. This is related to the deformation of the droplets in the matrix phase and hence to the interfacial forces between the blend components. The results for these uncompatibilized blends are shown to be in agreement with the predictions of the emulsion model of Palierne. These predictions were used to obtain the interfacial tension between PS and PE, which was found to be between 2 and 5 mN/m at 200 °C and 4 ± 1 mN/m at 230 °C. Independent interfacial tension measurements using the breaking-thread method resulted in a value of 4.7 mN/m and 4.1 mN/m at 200 °C and 230 °C for the respective blends.

Nafaa Mekhilef

Papers

Morphological stability, interfacial tension, and dual-phase continuity in polystyrene-polyethylene blends

Phase inversion and dual-phase continuity in polymer blends: theoretical predictions and experimental results

Viscoelastic properties and interfacial tension of polystyrene–polyethylene blends

Miscibility behaviour of ethylene vinyl acetate/Novolac blends