Co-continuous Phase Morphology

Poly(styrene-co-butadiene) rubber and poly(acrylonitrile-co-butadiene) rubber latex mixture films were evaluated as precursors of polymer electrolytes. A 50 50 blend was the optimum for mechanical strength and ionic conductivity. A simple equivalent mechanical model for the relationship between the mechanical strength and the structure was developed, which gave good agreement with experimental results, including materials with co-continuous phase morphologies. 26 refs. 

Harrats, G. and N. Mekhilef, Co-continuous phase morphologies predictions, generation, and practical applications, in Micro- and Nanostructured Multiphase Polymer Blend Systems Phase Morphology and Interfaces, C. Harrats, S. Thomas, and G. Groeninckx (Eds.), Taylor Francis, CRC Press, New York, 2006. 

A lot of literature exists concerning the formation of co-continuous phase morphologies in uncompatibilized binary polymer blends. In general, the blend component with the lowest viscosity and highest volume fiaction forms the continuous phase, while the blend component with the highest viscosity and lowest volume faction forms the dispersed phase. The continuity of one phase within the other at low volume fractions depends on the... 

Contrary to the droplet-in-matrix, the mechanism and the control of the co-continuous phase morphology, where the two phases are continuous and interconnected throughout the whole volume of the blend, is still not well elucidated. The complexity arises mainly from the ambiguous effect of the viscoelastic characteristics of the components, their composition in the blends, and the magnitude of their interfacial tension. Several empirical expressions have been proposed so far to predict either the phase inversion or the conditions for which co-continuous morphology is generated. 

Important aspects relating to the development of phase morphologies in polymer-based multicomponent systems were discussed. Focus is made on the co-continuous phase morphology in binary and ternary thermoplastics blends. 

The key to solve problems of coarse morphology is to reduce interfacial tension in the melt and to enhance adhesion between the immiscible phases in the solid state. One solution is to select the most suitable blending technique so that co-continuous phase morphology can be obtained, which results in direct load sharing. The second solution is the addition of a third homopolymer or block or graft copolymer or low molecular reactive compounds, which is miscible with either of the two phases. This can be considered as non-reactive compatibilization. The third way is to blend suitably functionalized polymers, which are capable for specific interactions or chemical reactions (reactive compatibilization) [35],... 

Dhibar AK, Kim JK, Khatua BB. Co-continuous phase morphology of asymmetric compositions of polypropylene/high-density polyethylene blend by the addition of clay. J Appl Polym Sci 2011 119(5) 3080-92. 

The presence of co-continuous phase morphology, which consists of at least two coexisting, continuous, and interconnected phases throughout the whole blend volume, is the other important superstructural characteristic... 

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