Synthesis, Characterization and Dielectric Properties of Biphenyl Group Containing Polymaleimide and Cyanate Ester Copolymer

In order to improve the solubility and dielectric properties of maleimide resin, polymaleimide (PMI) was prepared from maleic anhydride and polyarylamine containing biphenyl group (PBPPA), which was synthesized from 4,4′‐bis(chloromethyl)‐1,1′‐biphenyl and aniline. The chemical structure and molecule weight of PBPPA and PMI were characterized by 1 H‐NMR, FT‐IR and GPC, respectively. The results showed that PBPPA and PMI were successfully prepared, and there was a mixture of oligomers with different molecular weights. PMI presented excellent solubility and the solubility of PMI in toluene and 2‐butanone at room temperature was greater than 70%. Then PMI was mixed with bisphenol A cyanate (BADCy) at different mass ratios to prepare PMI/BADCy mixtures. The cured PMI/BADCy blends exhibited excellent comprehensive thermal properties. Among them, the 5% thermal decomposition temperature of P(BT‐8/2) reaches 392°C, the residual carbon rate at 800°C is 48.6%, the glass transition temperature is 323°C, the dielectric constant at 10 GHz frequency is 2.935, and the dielectric loss is 0.00572. These results indicated that the PMI/BADCy blends can be candidates for the application of high‐performance electronic packaging and communication, and their excellent comprehensive performance enables them to meet the increasingly stringent requirements of modern high‐end electronic equipment for materials.