Thermally stable homo- and copolyimides based on pyrimidine

Structural, thermal, and deformation and strength characteristics of films and fibers based on polyimides and copolyimides containing various combinat ions of unsubstituted and substituted 2,5- and 2,4-pyrimidylene fragments w ere studied. The structural organization of these polymers ensures their un ique thermal stability and strength. A scheme of spatial organization of ho mo- and copolymerization with pyrimidine rings and a number of aromatic dia nhydrides is proposed. This scheme takes into account the maximal interchai n interaction of the constituent moieties for the layer-by-layer and sheare d packing of the polyimide chains.