Synthesis of Poly(benzothiazole) by Direct Polycondensation of Dicarboxylic Acids with 2,5-Diamino-1,4-benzenedithiol Dihydrochloride Using Phosphorus Pentoxide/Methanesulfonic Acid as Condensing Agent and Solvent

Abstract

ABSTRACT:A convenient method for the synthesis ofpoly(benzothiazole)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aliphatic, alicyclic, and aromatic dicarboxylic acids containing phenyl ether structures with 2,5-diamino-1,4-benzenedithiol dihydrochloride using phosphorus pentoxidelmethanesulfonic acid (PPMA) as both a condensing agent and solvent. Polycondensations proceeded smoothly and were completed within several hours at 140oC to produce poly(benzothiazole )s with inherent viscosities up to 2.9 dl g-1 • The thermogravimetry of the aromatic poly(benzothiazole)s showed 10% weight loss in air and nitrogen at 405--490°C and 450-595°C, respectively.

Rigid‐Rod Polymers: Synthesis, Processing, Simulation, Structure, and Properties

“…PPMA has been applied to the polymerization of poly(2,5‐benzoxazole) 28. Attempts to synthesize modified PBZTs in PPMA have been reported as well 29,30…”

“…The poly(benzobisthisazole‐imide)s obtained were found to be soluble in strong acids, and some even dissolve in polar aprotic solvents such as dimethylformamide and dimethylsulfoxide 252. Aliphatic PBO253 and PBZT30,254 were prepared by using a series of aliphatic diacids as acid monomers. PBO polymers from the polycondensation of glutaric, adipic, suberic and sebacic acids with 4,6‐diaminoresorcinol dihydrochloride in PPA had peculiarly high inherent viscosities (5.4–26.8 dL/g in MSA at the concentration of 0.05 g/dL at 25 °C) in comparison to the normal solution behavior of coil‐like polymers 253.…”

Polymeric Heat Exchangers: Effect of Chemistry and Chemical Composition to Their Performance

“…A heterocyclic aromatic polymer with outstanding thermal stability [14], polybenzothiazole ( Fig. 3.11), is made by a reaction between 3,3'-mercaptobenzidine and diphenyl phthalate.…”

Synthesis and Characterization of Aromatic Poly(benzobisthiazole)s and Poly[oxy(bisbenzothiazole)]s Containing Flexible Linkages

“…[13 -15, 19] We selected the latter route, which does not require the preparation and purification of diacid dichlorides. Initial synthesis efforts were directed toward the polycondensation of monomer 4 with diacids 1-3 using PPMA as both condensing agent and solvent, at 140 8C, following, with some modifications, the method reported by Ueda et al [15] Tetramethylene sulfone, in fact, was added to PMMA as an inert co-solvent in order to enhance the solubility of the multi-ring diacids in the reaction mixture. Different monomer concentrations were used according to the solubility of the monomers.…”

“…As for other rigid etheroaromatic polymers, such as poly(oxadiazole)s [4] or poly(benzoxazole)s, [5 -7] considerable research efforts have been directed toward modifying the chemical structure of rigid-rod PBTs using specialized monomers in order to improve their solubility and/or to lower their transition temperatures while preserving high thermal stability. The modifications reported were obtained using fluorinated [8,9] or non-coplanar monomers, [10] by attaching flexible side chains [11,12] or bulky aromatic substituents [13] and incorporating diphenoxybenzene units [14,15] into the polymer backbone. The PBT derived from 4,49-(hexafluoroisopropylidene)dibenzoic acid and 2,5-diamino-1,4-benzenedithiol hydrochloride was found amorphous and exhibited improved solubility characteristics.…”