Synthesis and characterization of segmented copolymers of polystyrene and thermotropic liquid crystalline poly(4-oxybenzoate-co-2,6-oxynaphthoate)

Abstract

A series of segmented copolymers containing a thermotropic liquid crystalline poly(4-oxybenzoate-co-2,6-oxynaphthoate) and an amorphous polystyrene were created and analyzed. The segmented copolymers were prepared by solution polycondensation of α,ω-dicarboxylic acid-terminated polystyrene with 4-hydroxybenzoic acid and 2-hydroxy-6-naphtholic acid in a mixture of triphenylphosphine, hexachloroethane, and pyridine. The obtained polymers were fractionated to isolate the pure segmented copolymers. The segmented copolymers were characterized by FT-IR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, optical polarizing microscopy (OPM), and X-ray diffraction measurement. OPM and X-ray diffraction measurements verified the presence of a nematic liquid crystalline phase for the segmented copolymers. The experimental results indicate that the segmented copolymers have a microphase-separated morphology, that is both amorphous and liquid crystalline properties were shown by the polystyrene and liquid crystalline polyester segments respectively.

Synthesis and characterization of new nitrogen-rich polymers as candidates for energetic applications

“…[13][14][15] The investigation on the radical (co)polymerization, [16] radiation-induced bulk polymerization, [17] solution interdiffusion, [18,19] solution properties and kinetics of solution formation in various media, [20] rheological properties, [21] swelling thermodynamics, [22] and thermal degradation and its kinetics and mechanism of the PVT has been reported. Well-known technique for the preparation of the PVT is traditional radical polymerization of 5-vinyltetrazole monomer, [23,24] Considering that the 5-vinyltetrazole monomer is not readily available at the present time because of the absence of commercial source of 5-vinyltetrazole and also the difficulty in the synthesis of the 5-vinyltetrazole, [25][26][27] a new and powerful technique for the preparation of the PVT by tetrazole cyclization of polyacrylonitrile (PAN) could be a real challenge. This paper deals with an efficacious preparation and characterization of the PVT by the tetrazolation of the cyano groups in the PAN, that is, polymer-analogous conversion.…”