The Effect of Simultaneous Radical Polymerization of Poly( N -vinyl pyrrolidone)/α,ω-Bis(methacryloyloxy-poly(ethylene glycol)) on Physical Properties of Marine Polysaccharide

In order to expand the application in biomedical field of bio-derived polymers it is imperative that the issues related to their surface properties be addressed. Here we explore the approach of simultaneous radical polymerization to modify the surface properties of chitosan by grafting/crosslinking with poly( N -vinyl pyrrolidone) (PNVP)/α,ω-bis (methacryloyloxy-poly(ethylene glycol) (M-PEG) in the presence of potassium persulfate. The structure of the resultant copolymer membranes was proved by Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry. Scanning Electron Microscopy and Atomic Force Microscopy revealed the crosslinked copolymer membranes are porous materials with pore dimension, distribution and shape depending on the content of vinyl sequences. In addition, was revealed that the presence of vinyl crosslinked sequences linked to CS is disturbing the thermodynamic equilibrium conformation of CS. As a consequence, the ordering of CS chains into crystalline domains is reduced and the planes giving rise to the diffraction peaks are modified. Thus, the resultant copolymer membranes, depending by the weight ratio PNVP/M-PEG, became more amorphous. As a result of the crosslinking, the copolymer membranes were characterized by a smaller water swelling degree (about 300%) as compared with neat chitosan membrane (700%). The thermo-oxidative data have revealed an enhancement of the thermal stability of CS by crosslinking with PNVP/M-PEG copolymers. The water contact angles of the copolymer membranes proved to be more water wettable as compared to neat chitosan membrane.