US EPA

8712637 

Journal Article 

Solid-State Cross Polarization/Magic Angle Spinning 13C NMR Study of Thermotropic Aromatic Polyester Containing a Flexible Spacer in the Main Chain 

Uryu, T; Kato, T 

1988 

1 

Macromolecules
ISSN: 0024-9297
EISSN: 1520-5835 

21 

2 

378-384 

English 

10.1021/ma00180a015 

The solid-state structure of a thermotropic aromatic polyester containing an aliphatic flexible spacer basedon terephthalic acid and 4,4'-dihydoxy-1,6-diphenoxyhexane has been investigated by highresolution solid-stateCP/MAS (cross polarization/magic angle spinning) 13C NMR. Samples of the polymer with different thermal histories, i.e., an original sample as obtained by low-temperature solution polymerization and once-melted samples with different cooling conditions, have been prepared in order to study the effect of the thermal history on the solid-state structure of the polymer. For the original sample, the solid-state spectrum shows that a conformation of the hexamethylene spacer is all-trans in the plane of the phenoxy group and that the ester linkage is nearly perpendicular to the plane of the aromatic ring. For the once-melted sample, it has been found that the conformations of the hexamethylenespacer and the ether linkage are a function of thermal history but that no appreciable change takes place about the ester linkage. The thermotropic aromatic ester compound bis(4-butoxyphenyl) terephthalate has also been characterized by solid-state and solution NMR. The conformation of the model compound is similar to that of the original sample of the polyester. 1988, American Chemical Society. All rights reserved.