Morphology and structure of MCLCPs

Extensive characterization of MCLCPs has resulted in the delineation of a fibrillar, hierarchical structure model which describes the microstructures that Jaffe and Sanger observed in a broad range of oriented fibers, extrudates and moulded articles. Three distinct fibrillar species are observed microfibrils that are about 50 nm, fibrils about 500 nm and macrofibrils that are about 5 m in size. 

Optical studies in polarized light of a uniaxially oriented MCLCP fiber or thin tape revealed textures that have been described as domain-like, with the domains observed in these oriented structures being about 0-5 jiim across and elongated along the fiber axis. Again, one possible explanation proposed for the colour variation between domains is that it is due to the serpentine trajectory of the molecules within a domain, compared to adjacent domains. 

As yet there seems to be no suitable model to describe the formation of the bands, although a consensus does seem to have been reached that they result from some kind of relaxation phenomenon after the deformation has ceased. Factors that are likely to play a role in determining the two key parameters in describing the bands— their period and maximum deviation angle—are chain length, stiffness and the different Miescowiz viscosity coefficient, as they will determine what mode of relaxation is likely to dominate. However, there are very little data available on these relevant quantities. 

From the periodicity of the bands it is clear that they correspond to some kind of supermolecular structure, with many molecules changing orientation systematically and in concert. Such macroscopic properties of MCLCP as the modulus will depend on the overall level of 

The molecular morphology is the underlying key to the behaviour of MCLCPs and dictates to a large extent the macro- and micromor-phological behaviour of MCLCPs. 

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