Abstract
Polyimides have been modified with reactive additives, including methylmethacrylate POSS (MMA-POSS), methacrylisobutyl POSS (MAI-POSS) and benzoxazine-bridged bis(trialkoxysilne) compound (BPA-APTES-Bz), to reduce the dielectric constants and increase the mechanical strength of polyimides.The MMA-POSS/PI composite film with 10 wt% MMA-POSS exhibits a 34 % increase in tensile strength and the MAI-POSS/PI composite film with 15 wt% MAI-POSS exhibits a 17 % increase in tensile strength, compared to with the neat PI sample. Addition of the POSS additives significantly decreases the dielectric constants (Dk) of the PI samples. At 5 GHz, the Dk values drop from 3.6 to 3.35 with PI composites having 15 wt% of MMA-POSS and to 3.09 with PI composites having 15 wt% of MAI-POSS. Moreover, the Dk value of the PI sample with 20 wt% of BPA-APTES-Bz is 3.11. A simple and effective approach to prepare low-Dk PI composite films has been developed.