Preparation and characterization of ABB graft copolymers

Poly(2-vinylpyridine-g-styrene)s were prepared by successive coupling reactions of polystyryl anion and poly-2-vinylpyridinyl anion prepared by anionic polymerizations, with trifunctional coupling agent, tris-bromomethylbenzene. Five samples were prepared and characterized. Their volume fractions of polystyrene graft,os, were determined to be 0.24, 0.34, 0.45, 0.58 and 0.67, respectively. Morphologies of the solvent-cast films of the samples were observed by transmission electron microscopy and small-angle X-ray scattering. It was revealed that two samples, with os of 0.24 and 0.34, show cylindrical structures, while the other three samples have alternating lamellar structures.