Kinetics of azo-initiated 1-vinyl-2-pyrrolidone polymerizations at low conversions in aqueous media

Abstract

ABSTRACT:The free-radical polymerization behavior of 1-vinyl,2-pyrrolidone (NVP) was studied at low conversions, using capillary dilatometry. The aqueous media were kept at neutral pH and the studies were conducted isothermally, at 40 or 45°C. The azo-type initiators used were 4,4Ј-azobis-4-cyanopentanoic acid (ACPA), 2,2Ј-azobisisobutyronitrile (AZBN), and 2,2Ј-azobis[2-(2-imidazolin-2-yl)propane dihydrochloride] (ABDH). The monomer concentration and initiator concentration ranges were 1.17-2.34 mol L Ϫ1 and 1-8 mmol L Ϫ1, respectively. The rates of polymerization (R p ) and orders of reaction with respect to NVP and the initiator were evaluated and the kinetic equations were found to be R p ϰ

Aqueous RAFT/MADIXpolymerisation of N-vinyl pyrrolidone at ambient temperature

“…Its exceptional film-forming and adhesive characteristics, pHstability, strong resistance to thermal decomposition in water, nontoxicity and biocompatibility undoubtedly positions PVP as one of the most interesting water-soluble polymers. 3 Polymerisation of N-vinyl pyrrolidone (NVP) has only been reported via a free-radical process, mostly in a diazo-, 4 photo- 5 and redox-initiated 6 fashion. Following the advent of radical polymerisation by reversible deactivation (RPRD) techniques, 7 it became possible to synthesise PVPs with predetermined molecular weights (M n ) and narrow dispersities (ä ¼ M w /M n ).…”

Free radical polymerization kinetics of monomers functionalized with AsO(OH)2 in aqueous media

“…Values corresponding to the slope of the linear fitting for the data were obtained. Such an increased dependence of the rate on the monomer may be an uncommon result but, from data available in the literature, one can show that, although an order of reaction of unity should be expected, a value greater than unity can be experienced in some conditions as reported for acrylic acid,31, 32 methyl methacrylate,33 acrylamide,34 1‐vinyl‐2‐pyrrolidone,35 and sodium acrylate 36…”

Kinetics and Mechanism of Synthesis of Carboxyl-Containing N-Vinyl-2-Pyrrolidone Telehelics for Pharmacological Use

“…The chain termination mechanism, which affects the order of the reaction rate with respect to the initiator in the radical polymerization of N-vinylpyrrolidone, remains a subject of discussion [35]. The possibility of both traditional bimolecular chain termination, [36] and firstorder chain termination, in terms of the concentration of active centers, which are often associated with the participation of impurities in chain termination [27,35,37], has been shown. However, the development of the gel effect at high conversions of N-vinyl-2-pyrrolidone, noted in [27], rather indicates the realization of bimolecular chain termination.…”