Preparation, molecular weight determination and structural studies of (polyvinylpyrrolidone)-oximate silico-benzoyl glycine copolymer with IR spectroscopy at pH 7

Abstract

Polyvinylpyrrolidone (PVP)-oximate silico-benzoyl glycine (POSBG), a glycine copolymer, has been prepared with PVP-oxime and benzoyl glycine in a 1 : 1 ratio, w/w, in ethanol medium. The ethanolic solution with silicic acid [Si(OH)4] as binder in same ratio was refluxed for 2–3 h resulting in colloidal solution, which was further refluxed for 2 h and cooled to 37°C for 15 min. After this, a whitish solid material settled, which was separated by vacuum filtration followed by washing several times with aqueous ethanol at ordinary conditions. The average viscosity molecular weights () of PVP-oxime and the copolymer were determined with their respective dilute aqueous solutions at pH 7. Primarily the calibration curves between the intrinsic viscosity [η] data and their respective molecular weights of PVOH (polyvinyl alcohol) (marker) have been obtained to determine the of oxime. Similarly the of the copolymer was determined with the [η] data of lysozyme (molecular weight = 24,000 g mol−1), Egg albumin (40,000 g mol−1) and Bovine Serum Albumin (BSA) (65,000 g mol−1). The IR spectra of the PVP-oxime and copolymer were recorded in Nujol, which do not depict band frequency of –OH group of the binder. The 1602, 1688, 1182 and 1127 cm−1 stretching vibration frequencies noted in the spectra infer the presence of –C = N, –C=O, –Si–O–Si– and –Si–O–C– functional groups, respectively, in the copolymer.