Amphiphilic graft copolymers with poly(oxy ethylene) side chains: supermolecular structure in solid state: I. WAXS studies

The supermolecular structure of graft copolymers having rigid backbones and flexible side chains was studied by WAXS. Copolymers of isopropyl pentachlorophenyl fumarate with styrene or N-vinyl-2-pyrrolidone were treated with amino functionalized polyoxyethylene thus preparing graft copolymers with polyoxyethylene (PEO) side chains. Changes in the backbone structure, grafting degree and side chain length (Mn=750, 2000 and 5000) affect the PEO lattice parameters and supermolecular structure. A broad halo with a maximum at 6.5–7°θ (CuKα) was observed. This halo was attributed to scattering by a microphase, formed mainly by the noncrystallized main chains. DSC studies of the same copolymers are in favor of this suggestion since the DSC curves reveal two endothermic peaks: a PEO melting endothermic peak and a higher temperature broad peak arising from the isotropization of the rigid main chains. The copolymers with PEO-750 side chains tend to form a crystal structure which differs from the known PEO crystal lattices. The list of d-spacing of this lattice were calculated.