Abstract
Recently,benzoxazinehasbeenreportedasanewhighperformancethermosettingresinwithring-openingreactivity,whichhassuperiorpropertiessuchashighheat-resistance,highglasstransitiontemperatureandsmallvolumetricshrinkage.Varioushi-functionalbenzoxazinesarepreparedfromcorrespondingbis-phenolcompoundsforstudiesoftheirexothermichardeningbehaviour,thermaldecompositionandthermomechanicalpropertiesafterthermalcuringat200℃.Benzoxazineswithelectron-withdrawingspacerexhibitexothermichardeningatlowertemperaturefromtheresultsofdifferentialscanningcalorimetricanalysis.Thermaldecompositionofanycuredbenzoxazinescommenceinthevicinityof300℃,despitetheirdifferentstructuresinspacers.Inaddition,benzoxazinesexceptwithalkylsubstituentsinspacers,revielover50wt%ofresidualweightat700℃.Resultsofdynamicmechanicalanalysisonbenzoxazinesdemonstratethatthespacersaffecttheirhighmodulusandglasstransitiontemperatures.
