Der Pharma Chemica
Journal for Medicinal Chemistry, Pharmaceutical Chemistry, Pharmaceutical Sciences and Computational Chemistry


Amphiphilicgraft copolymers with hydrophobic poly(4-vinylpyridine) backbone and hydrophilic poly(n-vinylpyrrolidone) side chains synthesis and characterization

Author(s): Okkacha baba, Seghier Ould Kada and Masika Bradai

Macromonommers of 2-oxopropylmethacrylate-terminated poly(N-vinyl-2- pyrrolidone) is produced by cationic polymerization using HClO4 as an initiator. Termination (end capping) step is accomplished using 2- hydroxypropylmethacrylate (2HPMA) and the polymer product has different chain lengths of molecular weight averages ranging from 500 to 3000 g/mol. The study also synthesised amphipathic graft copolymers having hydrophobic poly(4-Vinylpyridine) as a backbone chain and hydrophilic poly(N-vinyl-2-pyrrolidone) (PVP) as side chains of various lengths. The copolymer synthesis was accomplished by free radical copolymerization of ω-oxopropylmethacrylate PVP in the presence of 4-Vinylpyridine using 2,2-azobisisobutyronitrile (AIBN) as an initiator. Measurements of the dynamic viscosity of the polymer solution (20% weight of macromonomers in ethanol) show that the viscosity is proportional to the average molecular weights Mn. However, a reverse behavior of the viscosity variation with regard to Mn is observed for graft copolymer samples. The viscosity variation with respect to the graft copolymer mass must be due to steric effects, which are strongly pronounced in grafted copolymer chains. Appearance of the number of side chains attached to poly(4-Vinylpyridine) backbone reveals that the grafting reaction has occurred with good efficiency. The structure and composition of amphiphilic graft copolymers were characterized by, UV–visible, FTIR, 1H NMR, 13C NMR and spectroscopy.