Exploration of the synthesis method of quaternary copolymerized thermoplastic polyimide

Polyimide (PI), especially aromatic polyimide has excellent comprehensive performance, making it widely applied in the field of electronic packaging. However, many aromatic polyimides usually suffer from poor processability, which severely limits their application especially in the flexible copper clad laminate (FCCL) or the low temperature electronic package process of temparory bonding or debonding (TBDB). Herein, a quaternary copolymerized thermoplastic PI (TPI) is studied and the effect of several synthesis methods on the overall properties of TPI films are explored in details. The experimental results show good solubility of TPI films which is ascribed to the synergistic effect of flexible units, low coplanar and distorted dianhydride. Most importantly, our experimental results revealed that the synthesis methods had a limited effect on the thermal properties, compared with the dielectric and mechanical properties. Collectively, this work provides systematic guidelines for synthesis method based on a quaternary copolymerized thermoplastic polyimide system which are promising for high frequency applications of 5G era.