Step-Growth Propagation of High Molecular Weight Rigid Rod Polymers

摘要

The synthesis of two isomeric poly(benzothiazoles) via the self-polycondensation of two isomeric (o-aminomercapto)benzoic acids was investigated. Poly(2,6-benzothiazole) was prepared from 4-amino-3-mercaptobenzoic acid in polyphosphoric acid at concentrations of 3 to 10%. Intrinsic viscosities between 3 and 4.6 dL/g in methanesulfonic acid were obtained. The purity of the requisite monomer for poly(2,5-benzothiazole), namely, 3-amino-4-mercaptobenzoic acid, was not sufficient to obtain high molecular weight polymer. The polymers are candidate matrix resins for molecular composites with the rigid rod polymer, poly(p-phenylene benzobisthiazole) (PBT). (Author)