Propagation Rate Coefficient for Radical Polymerization ofN-Vinyl Pyrrolidone in Aqueous Solution Obtained by PLP−SEC

Abstract

Propagation rate coefficients, k p , of N-vinyl pyrrolidone (NVP) radical polymerization in aqueous solution have been measured via the pulsed-laser polymerization -size exclusion chromatography method (PLP-SEC) over an extended concentration range from 1.8 to 100 wt % NVP at temperatures between 2 and 60°C. The SEC analyses have been carried out by a modified procedure using dimethyl acetamide as the eluent. An about 20-fold increase of k p is observed in passing from NVP bulk polymerization to reaction in dilute aqueous solution. As with nonionized methacrylic acid (MAA), for which a similarly strong change in k p has recently been reported, the large solvent effect in NVP polymerization is assigned to intermolecular interactions resulting in a significant hindrance of internal rotational motion in the transition state structure for propagation. Some contribution from a minor change in activation energy may however not be ruled out. PLP-SEC studies carried out on aqueous NVP solutions to which either polyNVP or N-ethyl-2-pyrrolidone (NEP), the saturated analogue of NVP, have been added, demonstrate that k p depends on the molecular environment at the reactive site, which is affected by NVP (or NEP) content, but not by the polyNVP content. The lowering of monomer concentration during NVP polymerization to higher degrees of monomer conversion results in an increase of k p . Variation of pH in the range 3 to 10 does not affect k p .

Kinetics of the Aqueous-Phase Copolymerization of MAA and PEGMA Macromonomer: Influence of Monomer Concentration and Side Chain Length of PEGMA

“…However, it has been found that for AM [18] and NVP [22], the pH does not affect the propagation rate coefficient.…”

“…Thus, in the last twenty years, several research groups have systematically analysed the effect of monomer concentration on the propagation rate coefficient, k p , of the most common water-soluble monomers including acrylic acid (AA) [13][14][15][16], acrylamide (AM) [17,18], methacrylic acid (MAA) [19][20][21], N-vinyl pyrrolidone (NVP) [22] and N-vinyl formamide (NVF) [23,24]. Very recently, Smolne et al [1] have also determined the propagation rate coefficient of poly(ethylene glycol) methyl ether methacrylate (PEGMA) in aqueous phase at different concentrations.…”

Monte Carlo simulation on kinetics of batch and semi-batch free radical polymerization

“…In their Predici TM simulation, [30] As found in experimental studies, the propagation constant kp increases as initial monomer concentration decrease. [32] It is believed that kp values should increase along with the monomer conversion owning to the decreasing of monomer concentration. [28] However, our , Pa = 0.012, Pt = 1.0) as those in batch FRP and continuously feed monomer into reaction system to mimic a semi-batch process.…”

Anwendung von Poly(ethylenglycol) beim Wirkstoff‐Transport: Vorteile, Nachteile und Alternativen

“…[189] [190] PVP kann durch freie radikalische Polymerisation von Vinylpyrrolidon sowie durch kontrollierte radikalische Polymerisation hergestellt werden. [174] Die zweite Methode ermöglicht niedrige PDI-Werte unterhalb von 1.2, [182,[191][192][193] variable Endgruppen [182,194] [195] Das erfolgreichste Konjugat, ein 28-kDa-PHPMADoxorubicin-Copolymer (8.5 Gew.-%; Doxorubicin PK1; klinische Studie Nr. FCE 28068 Phase III; Schema 4), wurde für mehrere Krebsarten getestet (Tabelle 3) und zeigte dabei Wirkung bei NSCLC, kolorektalen Tumoren und Mammakarzinomen.…”