Epoxy Resin/Poly(Phthalazinone Ether) Blends And Composites

Epoxy resins possess excellent comprehensive properties and processability,which makes them extensively applied as high performance composite matrix,coatings and adhesives.However,the characteristic brittle limits their applications.In this work,two novel high performance thermoplastics,poly(phthalazinone ether sulfone ketone)(PPESK) and poly(phthalazinone biphenylene ether sulfone)(PPBES),were used to toughen epoxy resin by blending.And continuous S-glass fiber and T700 carbon fiber reinforced unidirectional composites of two blends were prepared.The structures and properties of blends and their composites were studied for their application consideration.PPESK or PPBES powders were used to prepare the above mentioned toughening blends. The two blends with different compositions,PPESK/epoxy resin E-51/4,4'-diamino diphenyl sulfone(DDS)and PPBES/E-51/DDS,were prepared by PPESK or PPBES powder suspending in E-51/DDS acetone solvent.Differential scanning calorimetry(DSC)and Scanning electron microscope(SEM)were used to investigate the structures of the blends. The results indicate that the blends show slight phase separated structures and only a glass transition temperature similar to pure E-51/DDS is determined.The impact strength and fracture toughness(K_IC)of two blends were also studied,which show different tendency with the introduction of the two thermoplastics.For PPESK/E-51/DDS blends,impact strength and K_ICgo to the maximum as PPESK content increases to 20phr.For PPBES/E-51/DDS blends, impact strength goes to the maximum as PPBES content is 10phr,and K_ICgoes to the maximum at PPBES content of 20phr.On the basis of these studies,the continuous S-glass fiber and T700 carbon fiber reinforced unidirectional composites of two blends were prepared by PPESK or PPBES powders/E-51-DDS/acetone suspending solvent impregnating methods.The mechanical properties of two composites were investigated.The results indicate that viscosities of suspending solvent increase with the increase of PPESK or PPBES contents,and with the introduction of PPESK or PPBES,flexural strengths of the composites show a slightly decrease and interlaminar shear strength increase and water absorptions change a little.