ABSTRACT
One can assume the following reason of pseudomonomolecular reaction elapsion just in loosely packed regions of PBT and PBT+Z compositions. Roughly speaking, pseudomonomolecular reaction assumes the interaction of two polymeric macromolecules in thermal degradation process and this means the necessity of molecular mobility definite degree ensuring indicated interaction. As it was known [15], in contrast to zero molecular mobility can be realized only in loosely packed regions of semicrystalline polymers.