| abstract |
A thermotropic copolyester, showing a liquid-Âcrystalline structure of nematic type within a desired temperature range, contains umits deriving from:n (a) a saturated bicarboxy aliphatic acid; (b) 4,4′-di-hydroxy-biphenyl; (c) 4-hydroxybenzoic acid; and (d) 4-hydroxy-benzoic acid bearing an alkyl substituent or a halogen atom bonded to the aromatic ring. n Such a copolyester constitutes a material endowed with self-reinforcing characteristics, originating, through the usual transformation processes by injection or by extrusion techniques, marked molecular orientations, which supply the manufactured articles with high stiffness characteristics. n Said material can be also used as a reinforcing agent when is mixed, by means fo the usual techniques, with the traditional thermoplastic polymers. |