TY - JOUR
T1 - Chiral liquid‐crystalline polymers. XI. Thermotropic behavior and chiroptical properties in solution of a new series of optically active poly (ester β‐sulfide)s
AU - Chiellini, E.
AU - Galli, G.
AU - Angeloni, A. S.
AU - Laus, M.
PY - 1990/12
Y1 - 1990/12
N2 - The synthesis and characterization are described of a series of optically active semiflexible poly(ester β‐sulfide)s 6*Sn with repeating units constituted by two p‐oxybenzoyl diads spaced in an alternating fashion by a sulfide‐containing polymethylene segment of variable length (n = 2‐10) and a chiral (R)‐3‐methylhexanediyl segment of high enantiomeric purity. The polymers were prepared with good yields and relatively high molecular weights and narrow degrees of dispersity by a Michael‐type polyaddition reaction of bis‐thiols to the same chiral mesogenic bisacrylate monomer. Data are reported on the characterization of their chiroptical properties in dilute solution and thermal‐optical properties in the bulk, with attention being devoted to the distinct odd‐even alternations of the cholesteric‐isotropic melt transition parameters. A comparison of the mesomorphic behavior and relevant thermodynamic quantities is presented between the present series of polymers and the achiral analogues of series 6Sn as well as the chiral, positional isomers of series mS6*. The dependence of the overall properties and their trends on very subtle structural changes is stressed, thus highlighting the critical interconnection between mesogenic cores and spacer segments in semiflexible liquid‐crystalline polyesters.
AB - The synthesis and characterization are described of a series of optically active semiflexible poly(ester β‐sulfide)s 6*Sn with repeating units constituted by two p‐oxybenzoyl diads spaced in an alternating fashion by a sulfide‐containing polymethylene segment of variable length (n = 2‐10) and a chiral (R)‐3‐methylhexanediyl segment of high enantiomeric purity. The polymers were prepared with good yields and relatively high molecular weights and narrow degrees of dispersity by a Michael‐type polyaddition reaction of bis‐thiols to the same chiral mesogenic bisacrylate monomer. Data are reported on the characterization of their chiroptical properties in dilute solution and thermal‐optical properties in the bulk, with attention being devoted to the distinct odd‐even alternations of the cholesteric‐isotropic melt transition parameters. A comparison of the mesomorphic behavior and relevant thermodynamic quantities is presented between the present series of polymers and the achiral analogues of series 6Sn as well as the chiral, positional isomers of series mS6*. The dependence of the overall properties and their trends on very subtle structural changes is stressed, thus highlighting the critical interconnection between mesogenic cores and spacer segments in semiflexible liquid‐crystalline polyesters.
UR - http://www.scopus.com/inward/record.url?scp=0025627228&partnerID=8YFLogxK
U2 - 10.1002/pola.1990.080281302
DO - 10.1002/pola.1990.080281302
M3 - Article
SN - 0887-624X
VL - 28
SP - 3541
EP - 3550
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
IS - 13
ER -