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The compatibilization by transesterification of aromatic thermotropic liquid crystal polyesters (Ar-TLCP's) and TLCP's containing aliphatic ethylene-terephthalate (ET) linkages has been studied. Three Ar-TLCP's were mixed with two p(ET/HBA)'s, each having different extents of blockiness, to form a series of binary blends (Bin-TLCP's). The morphology and physical properties of the resultant Bin-TLCP's depend on the block structures, compositions, viscosities, and susceptibility to transesterification of the components. In this work, the influence of TLCP block structure and transesterification on the compatibility of the components of the Bin-TLCP's is described.

A thermotropic liquid crystalline polymer (TLCP) containing aliphatic linkages exhibits properties of both a random-coil and a rigid-rod. By varying its block structure, one can change its ability to form compatible blends with other polymers. In this work, the ability of the TLCP p(ET/HBA60) with a high degree of block structure, X-7G TM , to form compatible blends with polycarbonate and aromatic TLCPs is compared to that of a p(ET/HBA60) with a more random molecular structure, Rodrun TM LC-3000. It was found that both materials formed compatible blends through transesterification of the block structure and that a higher degree of blockiness enhanced the rate of transesterification. NMR spectra and differential thermal analysis were used to quantify the degree of transesterification and scanning electron microscopy was utilized to examine the effects of the blending process on the degree of compatibilization and the morphology of the resulting blends.