| abstract |
A thermoplastic polyester, polyamide or poly(ester- amide) which comprises at least one mesogenic unit of the formula:n nwherein:n Ar, and Ar 2 , which may be the same or different, each represent a divalent aromatic residue conjugated with the other; R, and R 3 , which may the same or different, each represent a hydrogen atom or a monovalent substituent group; and R 2 represents (i) a bis-multiply-bonded group of the formula:n nin which: R 4 represents a monovalent substituent group; and Q 1 and Q 2 , which may the same or different, each represent a nitrogen atom or a CR S group wherein R 5 represents a hydrogen atom or a monovalent substituent group; and p represents zero or a number not greater than 4; or R 2 represents (ii), together with R 1 and R 3 , a triple bond. |