A critical volume fraction of the minor component within the major component can be distinguished above which the co-continuous morphology in a polymer blend remains stable during annealing of the blend. Below this volume fraction breakup leads to a transition of the co-continuous structure to a dispersed one. This critical composition can be understood by depicting the co-continuous structure as an assembly of fibres randomly oriented at their maximum packing density. These fibres have 'coalesced’ at their cross-over points. The length of the filament between two cross-over points decreases with increasing volume fraction of the minor phase. At a certain length the dominant wavelength of the sinusoidal disturbances is larger than the length between two cross-over points and the disturbances will not grow further. Consequently, the filament cannot break up. The critical volume fraction above which breakup of the co-continuous structure during annealing is not possible, is found to be around 30 vol% of the minor phase.
Посилання на статтю:
Polymer Communication Co-continuous morphologies in polymer blends:stability / R.C. Willemse // Polymer. – 1999. – N 40. – P. 2175–2178.