Determination of order parameters in thermotropic aromatic polyesters containing mesogenic and flexible fragments in the main chain

Practical considerations in the study of main-chain thermotropic liquid-crystalline polymers by vibrational microscopy

“…In order to illustrate several points, the thermotropic polyester poly(oxytetraethyleneoxide-oxycarbonyl-1,4-phenylene-oxyterephthaloyl-1,4-phenylcarbonyl), P4EGTOB, where the spacer unit, R (scheme 1) is -(CH 2 -CH 2 -O) 4 -, is considered because of its highly complex transition behaviour [43,56], as can be observed in the thermograms given in figure 2 in reference 43 for a series of heating and cooling cycles. This data combined with results from TOA and WAXD gives the approximate transitional diagram shown in scheme 2:…”

“…These can be essentially divided into two groups: orientational order [3][4][5][6][7][8][9][10][11], and thermotropic behaviour [5,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. With respect to the thermotropic properties, both temperature variable IR [6,13,15,18,[22][23][24][25][26] and Raman [19,24] spectroscopy have been employed, and clear correlations with the transition temperatures observed by TOA and DSC have been reported.…”