Synthesis, Phase Behaviour and Mechanical Properties of Poly(2‐methyl‐1,3‐propanediol‐4,4′‐bibenzoate)

Abstract

The synthesis and phase behaviour of PB32 is reported. The results indicate that PB32 develops a low‐ordered smectic mesophase of the type SmCalt. The slow formation of such a mesophase allows the quenching of the isotropic melt into an amorphous state so that both amorphous glass and smectic glass can be obtained, which exhibit different glass‐transition temperatures. Mechanical tests indicate that the macromolecular chains in the mesophase of PB32 can be oriented either parallel or perpendicularly in relation to the streching direction, depending on the deformation conditions. Solid‐state 13C NMR spectroscopy results show that the mobility of the chains is rather similar in both phases.magnified image

Self-Assembly of Flexible–Semiflexible–Flexible Triblock Copolymers

“…The smectic layer spacing amounted to 1.38 nm. These features are identical to those of the fibrous BB-3(2-Me) homopolymer, suggesting that in all of the fibrous copolymers the LC segments form the same SmCA structure, in which the backbone is mainly extended along the fiber axis.…”

Synthesis and structural studies of poly(tetramethyleneoxypropylene p, p´-bibenzoate)

“…One of the reasons is the proximity between the glass transition and the isotropization temperature, which hampers the molecular motions. In the literature, there are some works describing polymers that present double T g : one arising from the mesophase and the other one from the amorphous phase [16][17][18][19][20][21][22][23]. The use of an asymmetrical spacer in mesogenic polymers makes possible the observation of this phenomenon.…”

Effect of the intercalated/exfoliated nanostructure on the phase transformations of smectic polyester/layered silicate hybrids: Reinforcement of the liquid-crystalline matrix

“…Previous works [6][7][8][9][10][11][12] have shown that the nature of the spacer has strong effect on the liquid-crystalline behaviour and mechanical properties. We consider that these polyesters are adequate model systems for getting a better comprehension about the dispersion level effect (intercalated vs. exfoliated structures) on the liquid-crystalline character, besides analysing its effect on the reinforcement of the matrix.…”