Synthesis of High Molecular Weight Para-Phenylene PBI

A new class of aromatic polyamide materials has recently become commercially available which exhibit super mechanical properties. The properties are primarily connected to the all-para aromatic structure of these polyamides. This report is concerned with the synthesis of an all-para aromatic heterocyclic polymer system. A study has been conducted on the use of various monomers and polymerization conditions to obtain high molecular weight poly1,7-dihydrobenzo1,2-d4,5-d diimidazole -2, 6-diyl-1, 4-phenylene. The polycondensation of 1,3-diamino -4, 6-p-toluenesulfamido benzene with terphthalic acid and also the homopolymerization of a series of AB-monomers has resulted in a polymer with intrinsic viscosities as high as 5.0. The resulting high molecular weight rod-like all-para PBI, with its high temperature capability and its ability to crystallize, shows great promise as a thermally stable material which should exhibit superior mechanical properties.