Cyclomatrix Phosphazene Polymers via Alder-ene Reactions

Abstract

Cyclomatrix phosphazene polymers were synthesized by the Alder-ene reaction between tris(2-allylphenoxy)triphenoxy cyclotriphosphazene (APCP) and bis(4-maleimido phenyl) methane (BMM). APCP was synthesized from hexachlorocyclotriphosphazene by sequential reaction with sodium phenolate and sodium (2-allylphenolate). It was co-cured in various stoichiometric ratios with BMM. The cure of the APCP/BMM blend was characterized by differential scanning calorimetry, dynamic mechanical analysis, and rheometry. The polymers exhibited good thermal stability and anaerobic char yield. Although allylphenoxy phosphazene led to early initiation of thermal decomposition, it was conducive to a slow rate of thermal erosion and higher char residue. The cured polymers showed a Tg in the range of 240-250°C. They formed good uni-directional composites with glass fibres, although the phosphazene was found to marginally decrease the inter-phase bonding.