| Abstract
| - The synthesis and characterization of a new class of rigid-rod liquid crystalline polyesters[R(n)] bearing side groups is reported. R(n) were prepared by interfacial polycondensation of n-alkoxyterephthaloyl chloride and 3,3‘-diallyl-4,4‘-dihydoxybiphenol exploiting the good solubility inchloroform promoted by the side flexible groups. R(n) show a mesophase at room temperature, andcrystallize in some cases (n = 4−7) upon annealing. The crystalline phase has been resolved and refined(space group P21, 2 chains per unit cell). The molecular packing is characterized by a layered organizationof chains, with pendant groups placed between layers. At high temperature, R(n) show the nematic phase.Polymers can be processed to form fibers, with the exception of R(1) which cross-links very quickly inthe molten state. Heating at temperature over 200 °C or annealing in the solid-state induces cross-linkingof allyl groups. In the latter case, the macro-orientation of fibrous samples can be quenched. R(5) andR(10) each show a constant tensile modulus of 1 and 0.5 GPa, respectively, in the range of temperaturefrom about 150 to 300 °C.
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