Effect of poly(ether ether ketone) and allyl compounds on microstructure and properties of bismaleimide

Sulfonated poly(ether ether ketone) (SPEEK) was obtained by oxidizing poly(ether ether ketone) (PEEK) with concentrated sulfuric acid. Bismaleimide (BMI) resin was used as matrix; 3,3-diallyl bisphenol A (BBA) and bisphenol A diallyl ether (BBE) as reactive diluent; SPEEK as modifier. SPEEK/BBA-BBE-BMI composites were prepared with compression molding method. The modification effects of SPEEK and microstructure, mechanical properties, thermal stability and dielectric properties of composites are studied. Fourier-transform infrared spectroscopy, scanning electron microscope and energy dispersive spectrometer spectrum analysis show that sulfonation effect of SPEEK is obvious. The micromorphology of SPEEK/BBA-BBE-BMI composites shows that SPEEK exhibits a porous and two-phase structure, which uniformly disperses in matrix. The fracture morphology of rugged river pattern gives the composite excellent performance. Mechanical properties results indicate that the flexural strength, flexural modulus, and impact strength of composites are improved significantly; they are 147.93MPa, 4.15GPa and 15.74kJ/mm(2), which are higher 49.47%, 45.61% and 66.21% than those of matrix, respectively, when the content of SPEEK is 5wt%. The thermal decomposition temperature is 460 degrees C, which is 15 degrees C higher than that of matrix. Dielectric constant of composite is 2.415 at a frequency of 100Hz. Dielectric loss tangent of composites is slightly higher than that of matrix resin in the low frequency region. However, it appears to first decrease and then increase with the increases of SPEEK in the high frequency. Volume resistivity shows a peak value of 19.3x10(15)m at a frequency of 100Hz. The composite material properties are the best when the content of SPEEK is 5wt%.