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

Abstract

Polyvinylpyrrolidone (PVP)-oximate silico-benzoyl glycine (POSBG), a glycine copolymer, has been prepared with PVP-oxime and benzoyl glycine in 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 a 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. Primarily the calibration curves between the intrinsic viscosity (η) data and their respective molecular weights of polyvinyl alcohol (PVOH) (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 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.

Keywords:

• Average viscosity molecular weight [ M _v]
• PVP-oxime
• Silicic acid
• Benzoyl glycine
• Glycine copolymer
• Stretching vibration frequencies

Acknowledgements

The authors are highly thankful to Dept of Science and Technology, Govt of India, and Dr A.P. Raste, Principal, DBC, for infrastructural support. Mr Karamvir Chauhan, Vinod Chauhan, for moral support and encouragement and Dr. Sanjay Kumar for discussion.