LEWIS-ACID COORDINATION-COMPLEXES OF POLYMERS .1. BCL3, ALCL3, AND GACL3 COMPLEXES OF POLY(P-PHENYLENEBENZOBISTHIAZOLE)

Complexes of the rigid-rod polymer poly(p-phenylenebenzobisthiazole) ( PBZT) with the Lewis acids BCl3, AlCl3, and GaCl3 have been prepared, and their structures and properties are characterized. The complexes p repared by simultaneous complexation and solubilization in nitromethan e and those prepared by complexation without solubilization in dichlor omethane are shown to be identical. Complexation is found to occur by Lewis acid coordination of the sulfur and nitrogen heteroatoms of PBZT and the resultant complexes are of rigid-rod conformation in solution and have conjugated structures similar to the pure polymer. The solid AlCl3 and GaCl3 complexes are stable to 100 and 200-degrees-C in nitr ogen, respectively. The PBZT/GaCl3 complex exhibits a glass transition at about 26-degrees-C with an activation energy of 32 kcal/mol determ ined by differential scanning calorimetry and dynamic mechanical analy sis. The Lewis acid coordination complexes of the conjugated rigid-rod polymer PBZT are important derivatives that facilitate elucidation of its structural, chemical, and physical properties as well as intermed iates for facile processing of the pure polymer into films, coatings, fibers, and composites.