TY - JOUR
T1 - Synthesis and liquid-crystalline properties of thermotropic poly(ester-urethane)s
AU - Angeloni, A. S.
AU - Laus, M.
AU - Chiellini, E.
AU - Galli, G.
AU - Francescangeli, O.
N1 - Funding Information:
Acknowledgement-This work was supported by the “Progetto Finalizzato Chimica Fine II’ of the Italian National Council of Research (CNR).
PY - 1995/3
Y1 - 1995/3
N2 - Seven new mesogenic diol monomers CmCn, consisting of two bis(p-oxybenzoyl) units interconnected by a polymethylene segment containing n methylene groups and flanked by two linear ω-hydroxyalkyl segments containing m methylene groups were reacted with 1,6-hexamethylenediisocyanate (HDI) to give a new series of liquid-crystalline poly(ester-urethane)s HDI-CmCn. All of the precursors CmCn exhibited a nematic phase, and in two of them a smectic mesophase also occurred. Poly(ester-urethane)s HDI-CmCn were semicrystalline and formed a monotropic mesophase. The mesomorphic properties of the polymers were studied as a function of their chemical structure by changing alternatively m or n. The effect of the molecular weight of the polymers on the stability of the mesophase was also investigated for various samples of poly(ester-urethane) HDI-C6C6 (Mn = 3000-22,000). It was found that a competition existed between the tendencies of the polymer to crystallinity and liquidcrystallinity, and the molecular weight dependence of the crystallization temperature determined the onset of a monotropic mesophase.
AB - Seven new mesogenic diol monomers CmCn, consisting of two bis(p-oxybenzoyl) units interconnected by a polymethylene segment containing n methylene groups and flanked by two linear ω-hydroxyalkyl segments containing m methylene groups were reacted with 1,6-hexamethylenediisocyanate (HDI) to give a new series of liquid-crystalline poly(ester-urethane)s HDI-CmCn. All of the precursors CmCn exhibited a nematic phase, and in two of them a smectic mesophase also occurred. Poly(ester-urethane)s HDI-CmCn were semicrystalline and formed a monotropic mesophase. The mesomorphic properties of the polymers were studied as a function of their chemical structure by changing alternatively m or n. The effect of the molecular weight of the polymers on the stability of the mesophase was also investigated for various samples of poly(ester-urethane) HDI-C6C6 (Mn = 3000-22,000). It was found that a competition existed between the tendencies of the polymer to crystallinity and liquidcrystallinity, and the molecular weight dependence of the crystallization temperature determined the onset of a monotropic mesophase.
UR - http://www.scopus.com/inward/record.url?scp=0029273418&partnerID=8YFLogxK
U2 - 10.1016/0014-3057(94)00163-4
DO - 10.1016/0014-3057(94)00163-4
M3 - Article
SN - 0014-3057
VL - 31
SP - 253
EP - 258
JO - European Polymer Journal
JF - European Polymer Journal
IS - 3
ER -