Bio-based benzoxazine-terminated hyperbranched polyesters.

In this study, a novel bio-based benzoxazine-terminated hyperbranched polyester (HB-Dfa) was designed and synthesized using renewable diphenolic acid and furfurylamine as raw materials through self-polymerization and Mannich condensation reaction. Meanwhile, the copolymers based on HB-Dfa and benzoxazine monomer (P-ddm) were prepared to investigate the effect of HB-Dfa on the properties of traditional benzoxazine. The chemical structure of HB-Dfa was elucidated by fourier transform infrared (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopies. The curing behavior and curing kinetics were investigated by differential scanning calorimetry (DSC), showing that it possessed a low temperature of exothermic peak and activation energy value compared with the P-ddm. Hence, the curing process of P-ddm was facilitated by the introduction of HB-Dfa. The thermomechanical and thermal properties of P-ddm/HB-Dfa copolymers were determined by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. Compared with the pure P-ddm resin, the introduction of HB-Dfa remained most of glass transition temperature (T g), cross-linking density and thermal stability, which could promote the curing reaction and reduce the curing temperature of the copolymers. In addition, HB-Dfa exhibited a low dielectric constant (2.46 ≥ k ≥ 2.16) and a low dielectric loss (f ≤ 0.05) at frequencies range of 2–18 GHz, which could effectively modify the dielectric properties of the copolymer system. [Display omitted] • Fully bio-based benzoxazine-terminated hyperbranched polyesters was prepared. • HB-Dfa exhibits low activation energy and and soluble in various organic solvents. • Poly(HB-Dfa)s shows low dielectric constant at frequencies range of 2–18 GHz. • Copolymers with low cure temperature and dielectric constant and improved toughness. [ABSTRACT FROM AUTHOR]