Biobased and Colorless Polyimides With High Biomass Content and Transparency Derived From Camphor-Based Alicyclic...

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Conventional aromatic polyimides (PIs) exhibit coloration due to charge-transfer complex (CTC) formation, restricting their use in optoelectronics.
• Developing transparent and high-performance PIs from sustainable resources is crucial for advanced material applications.

Purpose of the Study:

• To synthesize novel biobased polyimides (CPIs) using camphor-derived diamines for improved optical transparency and thermal properties.
• To investigate the structure-property relationships of these biobased CPIs.

Main Methods:

• Synthesis of two camphor-derived alicyclic diamines (CA, CM) and one isosorbide-derived diamine (IS).
• Polymerization of these diamines with 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CB) and a spiro-norbornane dianhydride (Cp).
• Characterization of the resulting six biobased CPIs, evaluating optical transparency, film-forming ability, and thermal properties.

Main Results:

• Biobased CPIs derived from camphor diamines exhibited excellent optical transparency due to non-conjugated structures.
• The CM series, with enhanced chain flexibility, showed superior film-forming ability compared to the rigid CA series.
• CM-CB demonstrated balanced performance with 60% biomass content, high transparency (T400 = 82%), low yellowness (YI = 3), and a glass transition temperature >300°C.

Conclusions:

• Camphor-derived diamines are effective biobased building blocks for creating transparent polyimides.
• The developed biobased CPIs offer a promising alternative to conventional PIs for optoelectronic applications requiring high thermal stability and optical clarity.