Synthesis and Characterization of Novel Cardanol Based Benzoxazines

Benzoxazines are a class of phenolic compounds extensively studied in polymer science because of their properties as fiber reinforcements, fire-retardants and curing agents. In this article is described a solvent-less process, based on a Mannich reaction involving a primary amine and an aldehyde, for the preparation of new benzoxazines deriving from cardanol (a well known phenol obtained as a renewable organic resource and harmful by-product of the cashew industry). Particular attention is given to the synthesis and chemical characterization (both by H-1 NMR spectroscopy and HPLC), while the thermal polymerization process has been monitored by differential scanning calorimetry.