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

Morphology, miscibility and continuity development in poly(lactic acid)/poly(butylene adipate-co-terephthalate) blends

Cocontinuous polymer blends: influence of viscosity and elasticity ratios of the constituent polymers on phase inversion

The role of organoclay in promoting co-continuous morphology in high-density poly(ethylene)/poly(amide) 6 blends

The phase behavior and viscoelastic properties of the poly(methyl methacrylate) (PMMA) and poly(styrene-co-maleic anhydride) (SMA) blend systems have been investigated. In homogeneous region, the blends of different compositions behave as a classical polymer melt. On the other hand, in phase-separated region, the blends of symmetric and off-symmetric compositions show different characteristic thermorheological responses corresponding to the different morphologies, which has been confirmed by TEM analysis and qualitatively corroborated by utilizing Palierne’s emulsion model. Except for the well-known characteristic deviations of the storage modulus at low frequencies, the curves that describe the relationships between other rheological functions such as master curves obtained through time-temperature superposition (tTS) principle, van Gurp-Palmen Plots, Han Plots, and Cole-Cole Plots, also show significantly different shapes corresponding to symmetric and off-symmetric composition. Based on these findings we propose that such characteristic fingerprints can be used not only for marking phase separation but also for inferring the resulting morphology. It is also shown that van Gurp-Palmen Plots and Cole-Cole Plots are more sensitive than other rheological functions. In addition, on comparing the validity of tTS principle in different blend systems, we argue that the morphology is responsible for whether tTS principle holds or not for polymer blend.

Phase Behavior and its Viscoelastic Responses of Poly(methyl methacrylate) and Poly(styrene-co-maleic anhydride) Blend Systems

The phase inversion process was investigated from different points of view. First, a reliable on-line and off-line method of morphology detection using light microscopy is established. The method provides fast information that can be used to discriminate between different types of morphologies. Second, TEM images are modelled with Markov Random Fields. For characterization purposes image features are introduced and tested. A combination of features allows classification of different morphologies of PMMA/PS blends. In the third part we show that the rheological properties of blends allow also discrimination between different morphologies.

K. Borkenstein

Papers

Morphological and rheological detection of the phase inversion of PMMA/PS polymer blends