Synthesis, Characterization and Photocrosslinkable Studies of Certain Thermotropic Liquid Crystalline Poly(ester-amides)

Abstract

Five thermotropic liquid crystalline poly(ester-amides) were synthesized by polycondensation method using varying dicarboxylic acids with a common diamine namely 4,4-diaminodiphenyl and a common diol namely 2,6-bis(4-hydroxy-3-methoxybenzylidene)cyclohexanone (CHBV). The solubility data and viscosity measurements of these synthesized poly(ester-amides) were used for qualitative characterization. The spectroscopic techniques such as FT-IR, ¹H NMR, ¹³C NMR were performed for investigating micro structural features. By differential scanning calorimetry (DSC), the thermal phase transition behavior of these poly(ester-amides) was studied. Scanning electron microscopy (SEM) technique was used to investigate the morphology of these poly(ester-amides). By using UV-visible spectroscopic technique, the photocrosslinkability of these poly(ester-amides) were studied by irradiating these poly(ester-amides) under a 160 W medium pressure mercury lamp. SEM analysis of these UV irradiated poly(ester-amides) showed the changes in morphology. Thus, the poly(ester-amides) containing arylidene keto moiety in the main chain exhibited nematic mesophase and were photocrosslinked upon UV irradiation. X-ray diffraction (XRD) patterns of these poly(ester-amides) were taken to assess the degree of crystallinity.<div><br></div>