Studies on the thermotropic liquid-crystalline polymer. IX. Synthesis and properties of crosslinkable copoly(amide-ester)s containing conjugated double bonds

Four series of copoly(amide‐ester)s containing conjugated double bonds were prepared by using direct polycondensation in the presence of diphenylchlorophosphate (DPCP) and pyridine. Series I–III were prepared from para, meta‐aminophenol, or their mixture with p‐phenylene bis(acrylic acid) (PPBA), p‐carboxylic cinnamic acid (PCCA), and stilbenedicarboxylic acid (SDBA), respectively. Series IV was prepared from a mixture of aminophenols [2‐methyl 4‐aminophenol (MePAP) and m‐aminophenol (MAP)] with a mixture of diacids (PPBA and SDBA). Thermotropic liquid‐crystalline behavior of these polymers was studied by differential scanning calorimetry (DSC), and optical polarizing microscopy equipped with a heating stage. Series I, series II, and P40–P100 of series IV could undergo crosslinking reaction by heating. However, series III could undergo crosslinking reaction only by photoirradiation upon heating. After crosslinking reaction occurred, the properties of these polymers were also examined by DSC, TGA, WAXD, and IR. The synthesized polymers could be crosslinked in the liquid‐crystalline phase with retention of the order in the final crosslinked solid. © 1993 John Wiley & Sons, Inc.