Non-isothermal crystallization kinetics of poly(aryl ether ketone) resin and hygrothermal aging properties of its composites

Poly (aryl ether ketone) (PAEK)thermoplasticcompositescan replacesometraditional thermosettingcompositesbecauseoftheiroutstandingtoughness,agingresistance,fatigueresistance, low cost,high manufacturing efficiency and recyclability. Thus,PAEK composites have been successfullyappliedinforeignaviationandotherhigh-endindustrialfields.PAEKisakindofsemi-crystalline polymer. Hence,different molding process conditions of PAEK composites lead to different aggregation structures of resin matrix,which have significantinfluence on mechanical propertiesandagingresistanceofthecomposites.CrystallizationkineticsofdomesticPAEKresinwas studied.Then,continuouscarbonfiberreinforcedPAEKcompositeswithdifferentcrystallinitieswere prepared by mold pressing at different cooling conditions. The composites were subjected to hydrothermalagingtreatment.Flexuralproperties ofthecomposites wereevaluated.Theresults showthathighercoolingratescanimprovethecrystallizationrates butreducethecrystallinityof PAEKresin.Thecrystallinityof PAEK resinsofthecompositesprepared atfurnacecooling,air coolingand watercoolingareabout36.3%,29.7% and26.5%,respectively.Thus,thedecreaseof PAEKcrystallinityleadstothe decreaseofflexuralstrength ofitscomposites. Moreover,flexural strengthretentionratesofcomposites with differentcrystallinitiesafterhydrothermalagingtreatmentfor 240hare88.8%,86.7% and86.6%,respectively.Therefore,highercrystallinitycan betterresistthe damageofwaterontheinterfaceandimprovethehydrothermalagingresistanceofthecomposite.