Self-assembled nanostructure of polybenzoxazine resins from reaction-induced microphase separation with poly(styrene-b-4-vinylpyridine) copolymer

In this study, we synthesized the diblock copolymer poly(styrene-b-4-vinylpyridine) through nitroxide-mediated radical polymerization and then blended it with the monomer (3-phenyl-3,4-dihydro-2H-1,3-benzoxazin-6-yl)methanol (PA-OH). Fourier transform infrared (FTIR) spectroscopy revealed evidence for intermolecular hydrogen bonding between the pyridyl groups of P4VP and the OH group of PA-OH. Thermal curing resulted in the block copolymer being incorporated into the polybenzoxazine resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation, as evidenced using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). This approach also provided a variety of composition-dependent nanostructures, including disordered spherical, wormlike, and cylindrical structures through the intriguing balance between the contents of the polybenzoxazine and the diblock copolymer.