Introduction In the high-performance polyimide (PI) supply chain, CBDA (Cyclobutane-1,2,3,4-tetracarboxylic dianhydride) and DMCBDA (Dimethyl-cyclobutane-1,2,3,4-tetracarboxylic dianhydride) are two widely used dianhydride monomers. Both can endow polyimide materials with unique transparency and low dielectric properties, but they differ significantly in structure, performance, and application scenarios . For procurement managers, understanding these differences is essential for material selection and cost optimization . Structural and Performance Differences Between CBDA and DMCBDA Structural Differences CBDA : The basic cyclobutane tetracarboxylic dianhydride, molecular formula C₈H₄O₆, compact and symmetrical. DMCBDA : With two methyl substituents on the cyclobutane backbone, its molecular volume is larger with increased steric hindrance. This substitution difference directly affects the optical properties, thermal stability, and dielectric constant of the res...