American Journal of Polymer Science 2014, 4(1): 16-23 DOI: 10.5923/j.ajps.20140401.03 Reactivity Ratios of N-Vinylpyrrolidone - Acrylic Acid Copolymer P Hemalatha 1,* , M K Veeraiah 1 , S Prasanna Kumar 2 , Netkal M Madegowda 3 , M Manju 4 1 Department of Chemistry, Sri Siddhartha Institute of Technology, Tumkur 2 Clov Chem, India Private Limited, Harohalli, Bangalore 3 Department of Chemistry, Western Illinois University, Macomb, IL, USA 4 Department of Chemistry, Sri Krishna Institute of Technology, Bangalore Abstract Copolymers of N-vinylpyrrolidone (NVP) and Acrylic acid (AA) were prepared by using hydrogen peroxide as initiator and water as solvent at 45 ℃ under nitrogen atmosphere at different compositions. The copolymers were characterized by FTIR, H 1 NMR and C 13 NMR. The copolymer reactivity ratio was computed by the Fineman- Rose(F-R) and Kelen Tudos(K-T) method at lower conversion, using the data obtained by Acid - Value studies. The Copolymer microstructure and Sequence distribution of monomers in the copolymer was calculated by statistical method. Keywords N-vinylpyrrolidone, Acrylic acid, FTIR, H 1 NMR, C 13 NMR, Reactivity ratios, Sequence distribution 1. Introduction Copolymerization is one of the important techniques adopted in effecting systematic changes in the properties of the commercially important polymers. The chemical structure of copolymer depends not only on the monomer units forming the macromolecule but also how such units are distributed along macromolecular chains. This distribution is a direct consequence of each monomer’s reactivity in the copolymer molecule [1]. Reactivity ratios are the most important parameters for composition equation of copolymers and they offer information about the reactivity of monomer pairs. However, the copolymer composition is important in evaluating its own utility. The copolymer composition and its distribution are dependent on their reactivity ratios, which can be evaluated either by employing linear and nonlinear methods or by using other copolymer composition equations [2-4]. Many polymers with reactive functional groups are now being synthesized, tested and used not only for their macromolecular properties, but also for the properties of functional group. These groups provide an approach to a subsequent modification of the polymer for specific end application [5]. N-vinylpyrrolidone (NVP) has been widely investigated for applications in various Fields, [6-10] as these are known to exhibit good biocompatibility due to their hydrophilic nature and low cytotoxicity [11-13]. The amide group of * Corresponding author: phlssit@gmail.com (P Hemalatha) Published online at http://journal.sapub.org/ajps Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved NVP has a high binding affinity for several small and large molecules that are known as good hydrogen-bond acceptors and has been copolymerized with a variety of monomers [14-18]. S. Sundararajan et al. synthesized the copolymer of Glycidal Methacrylate and N- vinylpyrrolidone and the reactivity ratio was determined [19]. It indicates that Glycidal Methacrylate is more reactive and the copolymer formed is random in nature. S. Vijay Kumar et al. studied the reactivity ratio of N-Vinylpyrrolidone and Ethoxy ethyl methacrylate. They found out the reactivity ratio of the copolymer and the distribution of the monomer sequence along the copolymer chain was also calculated [20]. A.S. Brar et al. synthesized the copolymer of N-Vinylpyrrolidone – Methylmethacrylate by free radical bulk polymerization and they determined the reactivity ratio [21]. Dilek Solpan et al. synthesized copolymer N-Vinyl Pyrrolidone – Methylmethacrylate and they studied the swelling property of these hydrogels [22]. Mitesh.B.Patel et al. synthesized the copolymer of N-Vinylpyrrolidone – 2, 4 – Dichlorophenyl methacrylate and they determined that the reactivity ratio of both the monomers is less than unity [23]. They have also determined the Azeotropic composition of the copolymer. Nicolas Gatica et al. synthesized the copolymer of N-Vinylpyrrolidone – Vinyltrimethylsilane and N-Vinylpyrrolidone – Vinyltrimethoxysilane and reported that the copolymers formed are random [24]. In the present work a copolymer of NVP with acrylic acid (AA) is synthesized. The prepared copolymer is characterized by FTIR, H 1 -NMR and C 13 NMR. Reactivity ratios of monomer are calculated using Fineman- Rose (F-R) [25] and Kelen - Tudos(K-T) [26] methods at lower conversion, using the data obtained from Acid Value studies.