Journal of Polymer Science Part B: Polymer Physics, Vol.36, No.13, 2371-2378, 1998
Segmented liquid crystalline polyesters with allyl group as lateral substituent
The synthesis and a partial characterization of segmented liquid crystalline polymers with 3,3'-diallyl-4,4'-dihydroxybiphenyl unit in the rigid moiety is reported. The general formula of polymers is [-p-C6H4-COO-p-C6H3(R)-p-C6H3(R)-OOC-p-C6H4-O-(CH2)(n)O-](x), with n = 6, 8, 10, 12, and R = -CH2-CH=CH2. All polymers have nematic liquid-crystalline behavior. At room temperature, annealed fiber samples of polymers show a complex polymorphism. Three phases have been isolated with very large unit cells accommodating 6 or 12 chains. The projection of the molecular packing in a plane perpendicular to the c axis is characterized by the organization of chains in a two-dimensional hexagonal or quasi-hexagonal array.
Keywords:RIGID-ROD POLYESTERS;FLEXIBLE SIDE-CHAINS;PHASE-BEHAVIOR;MAIN CHAIN;THERMOTROPIC POLYESTERS;MESOGENIC POLYMERS;1;4-DIALKYL ESTERS;PYROMELLITIC ACID;POLYANHYDRIDES;4;4'-BIPHENOL