This study developed a continuous flow process for synthesizing the main-chain benzoxazine precursor BPA-hda, addressing the limitations of traditional batch methods. Under optimal conditions (130 °C, 10 min), the precursor was obtained with a yield of 80.83%, a ring-closed ratio of 95.0%, Mn of 5208 Da, and PDI of 2.24. Compared to batch synthesis, this process reduced reaction time by 96.7% while significantly improving molecular weight and distribution uniformity. Research indicates that under comparable cross-linking density, poly(BPA-hda) derived from narrow distribution (PDI ≈ 2.0) precursors exhibits superior properties: higher hydrophobicity (water contact angle >60°), lower dielectric constant (1.93 at 1 MHz), lower water absorption (<1.7%), and maintained exceptional corrosion resistance in 3.5 wt % NaCl for 60 days. This work achieves precise control of precursor molecular parameters via continuous flow technology and clarifies the structure–property relationship driven by molecular weight distribution.
Zhang et al. (Fri,) studied this question.