Vol. 7, Issue 2, Part A (2025)

Aromatic polyesters are valued for their thermal stability, chemical resistance, and mechanical strength, but poor solubility and high glass transition temperatures (Tg) limit their processability. To address this, two novel diols, 3,5-dihydroxy-N-(4-(naphthalen-8-yloxy)phenyl)benzamide (XV, 1-naphthyl) and 3,5-dihydroxy-N-(4-(naphthalen-7-yloxy)phenyl)benzamide (XVIII, 2-naphthyl), were synthesized and polymerized with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC) via interfacial polycondensation.
The resulting polyesters were characterized by FTIR and NMR, and their thermal properties were studied using TGA and DSC. All polymers showed decomposition onset above 150 °C with T10 values of 355-467 °C. The XVIII series exhibited higher char yields and Tg values (129-147 °C) compared to the XV series (109-129 °C), indicating greater rigidity and thermal resistance.
These results highlight the critical role of pendant group orientation in controlling thermal stability and chain mobility, offering design strategies for advanced high-performance polyesters.