By reacting a rigid rod epoxy terminated molecule (p-bis(2,3-epoxypropoxy)-alpha-methylstilbene) with an aliphatic carboxylic acid (decanedioic acid), a lightly crosslinked liquid crystalline network is obtained. This network exhibits a smectic-like phase. While the mesophasic structure resulted ''frozen'' by the crosslinks in the case of highly crosslinked liquid crystalline epoxy resins, in this case a reversible transition from the liquid crystalline to the isotropic phase is observed. Moreover, while curing the same rigid rod epoxy molecule with amines resulted in a thermoset with a nematic structure, in this case a more ordered mesophase can be obtained. Preliminary results show that it is possible to orient macroscopically the mesogenic chains by stretching thin films above the glass transition temperature (T-g) and then quickly cooling down to the glassy stale. This makes this material very attractive in the field of optical applications.
CURING OF A RIGID-ROD EPOXY-RESIN WITH AN ALIPHATIC DIACID - AN EXAMPLE OF A LIGHTLY CROSS-LINKED LIQUID-CRYSTALLINE THERMOSET
AMENDOLA E;
1995
Abstract
By reacting a rigid rod epoxy terminated molecule (p-bis(2,3-epoxypropoxy)-alpha-methylstilbene) with an aliphatic carboxylic acid (decanedioic acid), a lightly crosslinked liquid crystalline network is obtained. This network exhibits a smectic-like phase. While the mesophasic structure resulted ''frozen'' by the crosslinks in the case of highly crosslinked liquid crystalline epoxy resins, in this case a reversible transition from the liquid crystalline to the isotropic phase is observed. Moreover, while curing the same rigid rod epoxy molecule with amines resulted in a thermoset with a nematic structure, in this case a more ordered mesophase can be obtained. Preliminary results show that it is possible to orient macroscopically the mesogenic chains by stretching thin films above the glass transition temperature (T-g) and then quickly cooling down to the glassy stale. This makes this material very attractive in the field of optical applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
