A family of mono-, di- and trisubstituted benzylglycidylether derivatives with 4-dodecyloxybenzyloxy groups at the 4-, 3,5-, and 3,4,5- position of the aromatic ring was synthesized and characterized. These monomers were subsequently polymerized with an aluminium-based ionic-coordinative initiator, [(CH3)2CHO]2Al-O-Zn-O-Al[OCH(CH3)2]2 (the Teyssie catalyst) or an anionic initiator, potassium t-butoxide. Polymerizations by potassium t-butoxide gave rise to conversions below 50% in all cases and relatively low molecular weights. The resulting polymers exhibited liquid crystalline phases, which were smectic for the calamitic monomer and columnar for the tapered monomers. When the ionic-coordinative Teyssie catalyst was used, the conversion of monomer was almost quantitative according to the higher activity of this type of initiators. The molecular weights and degree of stereoregularity were higher. The results of mesophase characterization, by DSC, XRD and POM, suggested that higher molecular weights and stereoregularity increase the stability of the mesophase and give rise to more compact structures.
Influence of the side group shape on the arrangement of liquid-crystalline polyethers obtained by ring opening polymerization of oxiranes
2006
Abstract
A family of mono-, di- and trisubstituted benzylglycidylether derivatives with 4-dodecyloxybenzyloxy groups at the 4-, 3,5-, and 3,4,5- position of the aromatic ring was synthesized and characterized. These monomers were subsequently polymerized with an aluminium-based ionic-coordinative initiator, [(CH3)2CHO]2Al-O-Zn-O-Al[OCH(CH3)2]2 (the Teyssie catalyst) or an anionic initiator, potassium t-butoxide. Polymerizations by potassium t-butoxide gave rise to conversions below 50% in all cases and relatively low molecular weights. The resulting polymers exhibited liquid crystalline phases, which were smectic for the calamitic monomer and columnar for the tapered monomers. When the ionic-coordinative Teyssie catalyst was used, the conversion of monomer was almost quantitative according to the higher activity of this type of initiators. The molecular weights and degree of stereoregularity were higher. The results of mesophase characterization, by DSC, XRD and POM, suggested that higher molecular weights and stereoregularity increase the stability of the mesophase and give rise to more compact structures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
