Novel Chiral and Achiral Benzoxazine Monomers and Their Thermal Polymerization

New chiral and achiral benzoxazine monomers ( S )-α-3-methylbenzyl-3,4-dihydro-6,8-di- tert -butyl-2 H -1,3-benzoxazine and rac -α-3-methylbenzyl-3,4-dihydro-6,8-di- tert -butyl-2 H -1,3-benzoxazine were prepared by Mannich condensation from enantiomerically pure ( S -α) and racemic ( rac ) methylbenzylamine H 2 NCH(CH 3 )C 6 H 5, formaldehyde and 2,4-di- tert- butylphenol. Their DSC exhibit exotherms at 291 and 263 °C which correspond to oxazine thermal polymerization. The resulted polymers show very low T g values of 31 and 19 °C for poly- S - 1 and poly- rac - 1, respectively. Higher value for the polymer obtained from enantiomerically pure monomer results from the monomer derived stereoregularity of the polymer. A comparison of thermal stabilities of both polymers showed significantly lower heat resistance for the polymer obtained from racemic monomer. The resulted data are compared with those obtained for similar rac -α-3-methylbenzyl-3,4-dihydro-8-(1,1,3,3- tetra -methylbutyl)-2 H -1,3-benzoxazine with a free ortho position at the phenyl.