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-2 H -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 PAOH. Thermal curing resulted in the block copolymer being incorporated into the polybenzoxazine resin, forming a nano-structure 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.