1：Experimental Design and Method Selection:

The study involved synthesizing semi-aromatic polyimides via one-step high-temperature polycondensation using alicyclic dianhydrides (CHDA and BCDA) and aromatic diamines with ortho-substituted methyl and pendent phenyl groups. The methodology included polymerization in NMP or DMAc solvents with catalysts like isoquinoline, followed by thermal imidization.

2：Sample Selection and Data Sources:

Samples were prepared from specific monomers: CHDA and BCDA as dianhydrides, and BAPM, BAFM, BATFM as diamines. Data on molecular weight, solubility, thermal properties, mechanical properties, optical properties, and chemical resistance were collected.

3：List of Experimental Equipment and Materials:

Equipment included GPC system with MLLS, elemental analyzer (Flash EA1112), FTIR spectrophotometer (PerkinElmer 782), DSC (TA Q100), TGA (TA Q50), TMA (TA Q400), tensile tester (Instron 3365), UV-vis spectrophotometer (Hitachi U3900), colorimeter (X-rite Color i7), prism coupler (Metricon Model 2010/M), and X-ray diffractometer (Rigaku D/max-2500). Materials included NMP, DMAc, solvents, and monomers from suppliers like TCI and Sigma Aldrich.

4：0). Materials included NMP, DMAc, solvents, and monomers from suppliers like TCI and Sigma Aldrich. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Polymerization was conducted under nitrogen protection with stirring, heating to 180°C, and precipitation in ethanol. Films were prepared by dissolving PI resin in DMAc or NMP, doctor-blading on glass substrates, drying at 80°C, baking at 200°C and 300°C in nitrogen, and annealing at 310°C. Characterization involved solubility tests, chemical resistance tests by dipping in MEK and KOH solution, thermal analysis, mechanical testing, optical measurements, and XRD analysis.

5：Data Analysis Methods:

Data were analyzed using statistical methods for properties like molecular weight, thermal stability, mechanical strength, transmittance, color indices, refractive indices, and dielectric constants. DFT calculations were used for molecular orbital energies and structure optimization.