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Thermotropic polyesters: Synthesis and properties of poly( p ‐oxybenzoate‐ co‐m ‐phenylene terephthalate)s
Author(s) -
Brown Philip J.,
Karacan Ismail,
Liu Jing,
McIntyre J. Eric,
Milburn Alexander H.,
Tomka J. George
Publication year - 1991
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4990240105
Subject(s) - thermotropic crystal , materials science , phenylene , polyester , polymer chemistry , liquid crystal , copolymer , thermal stability , polymer , composite material , organic chemistry , liquid crystalline , chemistry , optoelectronics
DSC, TMA, hot‐stage microscopy and WAXS have been used to examine the effect of concentration of angular units and molecular weight on the thermal transitions of poly( p ‐oxybenzoate‐ co‐m ‐phenylene terephthalate)s. Copolymers containing molar fractions of m ‐phenylenedioxy units between 0·20 and 0·30 are melt processable nematogenic materials. In contrast, poly( p ‐oxybenzoate‐ co‐p ‐phenylene isophthalate)s remain nematogenic over a wider concentration range (0·20–0·40) of angular isophthaloyl units. Comparison of fibres produced from copolymers with the same fraction of angular units (0·25) indicates that those with isophthaloyl units have a higher modulus than those with m ‐phenylenedioxy units. These differences are ascribed to differences in planarity of chains containing isophthaloyl and m ‐phenylenedioxy units, respectively.