Low-dielectric styrene resins with high mechanical strength and good (re)processability via constructing imine-crosslinked network and introducing small amount of amino molecules

Materials used in circuit boards need to be recyclable in order to decrease resource waste and mitigate environmental pollution. However, it is challenging to prepare resins with high mechanical strength while preserving their good reprocessing and low dielectric property. In this study, an adaptable imine crosslinking network (imine-CAN) was constructed and a free amine compound (dodecylamine, DDA) was introduced to obtain styrene resins exhibited good (re)processability even at a high crosslinking density. The resin has a low dielectric constant of 2.71 and high mechanical strength of 52 MPa. Moreover, after reprocessing three times, the dielectric constants of the PS-imines remained constant and 94% mechanical strength was recovered. Further investigation indicated that the (re)processability and decrosslinking at high temperatures were regulated by incorporating different amounts of DDA. PS-imines showed superior mechanical and reprocessing performance compared to most current reprocessable resins. These new vitrimers could be potential candidates for use in recyclable circuit boards.