STUDY AND CONTROL OF PHASE MORPHOLOGY IN LIQUID-CRYSTAL POLYESTER POLY(ALKYLENE TEREPHTHALATE) BLENDS

Scanning electron microscopy (SEM) reveals that the morphologies of poly(hexamethylene terephthalate) (PHMT) and poly(p‐oxybenzoate co‐ethylene terephthalate) (LCP6/4) blends are biphasic. When LCP6/4 is the minor component, liquid crystalline domains are embedded in the matrix. The reaction in the melt between the polymers apparently increases the adhesion of the matrix to the embedded domains. As the reaction proceeds, the chemical composition of the matrix progressively becomes modified. High reaction temperatures, small particle size, mixing coupled with particle dispersion and high LCP6/4 content in the mixture promote the melt reaction and decrease the PHMT content in the polymer formed. At 260°C, the coaddition of di‐n‐octadecyl phosphite (DNOP) at a 2% weight fraction with PHMT and LCP6/4 inhibits the reaction between the polymers for 2 h. Copyright © 1990 John Wiley & Sons, Inc.