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High-performance composites with a resin matrix are urgently required for electronic packaging due to their low dielectric constant, outstanding high temperature resistance, excellent corrosion resistance, light weight and easy molding. In this work, hollow-glass-microsphere (HGM)-filled fluorinated-phthalonitrile (PBDP) composites, with filler contents ranging from 0 to 35.0 vol.%, were prepared in order to modify the dielectric properties of the phthalonitrile. Scanning electron microscopy (SEM) observations indicate that the modified HGM particles were uniformly dispersed in the matrix. The PBDP/27.5HGM-NH2 composite demonstrates a low dielectric constant of 1.85 at 12 GHz. The 5% thermogravimetric temperature (T5) of composites with silanized HGM filler (481–486 °C) is higher than the minimum packaging-material requirements (450 °C). In addition, the heat-resistance index (THRI) of PBDP/HGM-NH2 composites reached as high as 268 °C. the storage modulus of PBDP/HGM-NH2 composites were significantly increased to 1283 MPa at 400 °C, an increase by 50%, in comparison to that of PBDP phthalonitrile resin (857 MPa). The excellent dielectric and thermal properties of the present composites may pave a way for comprehensive applications in electronic packaging and thermal management for energy systems.

Three phthalonitrile monomers containing pyrimidine ring and benzene ring side group were successfully synthesized with 4, 6‐dichloro‐2‐phenylpyrimidine, three kinds of phenols (resorcinol, bisphenol A and bisphenol AF) and 4‐nitrophthalonitrile via nucleophilic substitution reaction. All the phthalonitrile monomers exhibited excellent processing performance due to low melting points (Tm) (below 100 °C) and wide processing windows (difference between melting temperature and curing temperature) above 140 °C. By introducing pyrimidine ring and benzene ring side group, the lower melting point of monomers did not affect the thermal stability and thermal mechanical properties of the phthalonitrile resins based on different bisphenols. In particular, 5 % thermal decomposition temperature (T5%) and glass transition temperature (Tg) of phthalonitrile resin based on resorcinol surpassed 455 and 400 °C while storage modulus (E′) was 3209 MPa. Therefore, phthalonitrile resin containing pyrimidine ring and benzene ring side group have potential applications in the field of high temperature resistant polymers and composites.

Phthalonitrile monomer with alkyl, pyrimidine, and amino is successfully prepared by nucleophilic substitution. The monomer is cured by autocatalysis of active hydrogen in the amino group, in order to obtain polymers through different temperature procedures. The low melting point (96°C) and curing kinetics of the monomer are analyzed by DSC, which manifest a processing window of 163°C. With lower energy barriers to overcome, the apparent activation energy ( E a) is 59.6 kJ mol−1 after fitting and calculating, signifying that the monomers are easier to process into polymers. This study focuses on the usefulness of the polymer, especially the long-term thermal stability by the comparison of numerous commonly used polymers. The consequence demonstrates that the polymer could be used for long periods at 300°C, keeping weight loss within 5 wt.% for 6 h. The advantage of long-term usage at high temperatures has not been proved in previous works on phthalonitrile polymer. Moreover, the thermal and thermal-mechanical stability are examined through TGA and DMA. The results indicate preferable thermal properties, that the glass transition temperature is up to 400°C.

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