The synthesis and the phase behavior of a set of polyether-polyesters characterized by having moderate chain flexibility and highly flexible lateral substituents are reported. The polymers are obtained from 2-alkoxyterephthaloyl chlorides and α,ω-bis(4-hydroxyphenoxy)alkanes and have the general formula (-p-C6H42OC-p-C6H4(OR)CO2C6H4O(CH2)nO-p-)x, with R = -(CH2)m-1CH3 (m = 5-8) and n = 2, 4. The presence of the lateral substituents, together with some chain flexibility, leads to comparatively low melting temps. (lower than ∼190° for annealed samples) allowing a nematic liq.-cryst. behavior to show up in a thermotropic, enantiotropic way. X-ray diffraction data collected for annealed fibrous samples at room temp. indicate that the structural periodicity along the fiber axis substantially corresponds to the length of the monomer unit in its most extended conformation. The same holds for fibers not annealed. In this case, however, the regularity of the chain packing both along and across the fiber axis is drastically disturbed such that the solid state should better be classified as a mesophase.
Mesomorphism in Segmented-Chain Polymers Containing Flexible Substituents in the Rigid Moiety
PRAGLIOLA, Stefania;IANNELLI, Pio
1995-01-01
Abstract
The synthesis and the phase behavior of a set of polyether-polyesters characterized by having moderate chain flexibility and highly flexible lateral substituents are reported. The polymers are obtained from 2-alkoxyterephthaloyl chlorides and α,ω-bis(4-hydroxyphenoxy)alkanes and have the general formula (-p-C6H42OC-p-C6H4(OR)CO2C6H4O(CH2)nO-p-)x, with R = -(CH2)m-1CH3 (m = 5-8) and n = 2, 4. The presence of the lateral substituents, together with some chain flexibility, leads to comparatively low melting temps. (lower than ∼190° for annealed samples) allowing a nematic liq.-cryst. behavior to show up in a thermotropic, enantiotropic way. X-ray diffraction data collected for annealed fibrous samples at room temp. indicate that the structural periodicity along the fiber axis substantially corresponds to the length of the monomer unit in its most extended conformation. The same holds for fibers not annealed. In this case, however, the regularity of the chain packing both along and across the fiber axis is drastically disturbed such that the solid state should better be classified as a mesophase.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
