Radical polymerization of N-vinylcaprolactam in benzene solutions in a wide conversion range

Kalugin, Denis; Talyzenkov, Yu. A.; Lachinov, M. B.

doi:10.1134/s1560090408110018

Cited by 13 publications

(9 citation statements)

References 2 publications

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“…The correlation coefficient was 0.999. This result differs from that obtained by Kalugin et al34 These authors observed that the polymerization is of first order with respect to the monomer. The fact that the dependence of the overall polymerization rate on monomer concentration is greater than first order can be associated with the dependence of the initiation rate on the monomer concentration and the greater impact of the gel effect at higher monomer concentrations, as explained by Scott and Peppas 32.…”

Section: Resultscontrasting

confidence: 99%

“…In this way, the dependence of polymerization rate on the initiator concentration was found to be R p ∝ [I] 0.52 . This result indicates that termination occurs through bimolecular interaction of growing chain radicals 31–46. The polymerization rate with respect to initiator concentration in this study is consistent with the classical kinetic theory, which predicts that the polymerization rate depends on the square root of the initiator concentration, as also indicated by some previous works 33, 47–49…”

Section: Resultssupporting

confidence: 91%

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Solution polymerization of N‐vinylcaprolactam in 1,4‐dioxane. Kinetic dependence on temperature, monomer, and initiator concentrations

Medeiros

Barboza

Ré

et al. 2010

J of Applied Polymer Sci

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The kinetics of the solution free radical polymerization of N-vinylcaprolactam, in 1,4-dioxane and under various polymerization conditions was studied. Azobisisobutyronitrile and 3-mercaptopropionic acid were used as initiator and as chain transfer agent (CTA), respectively. The influence of monomer and initiator concentrations and polymerization temperature on the rate of polymerizations (R p ) was investigated. In general, high conversions were obtained. The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to the monomer was greater than unity. The overall activation energy of 53.6 kJ mol À1 was obtained in the temperature range 60-80 C. The decreasing of the absolute molecular weights when increasing the CTA concentration was confirmed by GPC/ SEC/LALS analyses. It was confirmed by UV-visible analyses the effect of molecular weights on the lower critical solution temperature of the polymers. It was also verified that the addition of the CTA influenced the kinetic of the polymerizations.

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Section: Resultscontrasting

confidence: 99%

Section: Resultssupporting

confidence: 91%

Solution polymerization of N‐vinylcaprolactam in 1,4‐dioxane. Kinetic dependence on temperature, monomer, and initiator concentrations

Medeiros

Barboza

Ré

et al. 2010

J of Applied Polymer Sci

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“…In case of VCL, Kalugin et al performed calorimetric studies of the radical polymerization of VCL in benzene. Although they did not determine the reaction rate constants directly, they concluded from their experiments that the polymerization rate constants of VCL must be around 1 m 3 /mol s, by assuming that the rate constant of the bimolecular termination is of the same order as for most vinyl monomers .…”

Section: Methodsmentioning

confidence: 99%

Prediction of Chain Propagation Rate Constants of Polymerization Reactions in Aqueous NIPAM/BIS and VCL/BIS Systems

2017

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Microgels have a wide range of possible applications and are therefore studied with increasing interest. Nonetheless, the microgel synthesis process and some of the resulting properties of the microgels, such as the cross-linker distribution within the microgels, are not yet fully understood. An in-depth understanding of the synthesis process is crucial for designing tailored microgels with desired properties. In this work, rate constants and reaction enthalpies of chain propagation reactions in aqueous N-isopropylacrylamide/N,N'-methylenebisacrylamide and aqueous N-vinylcaprolactam/N,N'-methylenebisacrylamide systems are calculated to identify the possible sources of an inhomogeneous cross-linker distribution in the resulting microgels. Gas-phase reaction rate constants are calculated from B2PLYPD3/aug-cc-pVTZ energies and B3LYPD3/tzvp geometries and frequencies. Then, solvation effects based on COSMO-RS are incorporated into the rate constants to obtain the desired liquid-phase reaction rate constants. The rate constants agree with experiments within a factor of 2-10, and the reaction enthalpies deviate less than 5 kJ/mol. Further, the effect of rate constants on the microgel growth process is analyzed, and it is shown that differences in the magnitude of the reaction rate constants are a source of an inhomogeneous cross-linker distribution within the resulting microgel.

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“…The synthesis and the bulk polymerization PNVCL was later described in English by Solomon et al in 1968 [156]. The free-radical synthesis of PNVCL has been performed in many different solvents over the years, including benzene [173][174][175], toluene [156], isopropanol [149], DMF [151,153,154,176,177], DMSO and water mixture [178] and p-dioxane [159,179]. Recently, the synthesis of the polymer has been reported in water [158] and alcohol-water [180].…”

Section: Poly-n-vinylcaprolactammentioning

confidence: 99%

Chitosan-Based Biocompatible Copolymers for Thermoresponsive Drug Delivery Systems: On the Development of a Standardization System

Marsili

Berti

et al. 2021

Pharmaceutics

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Chitosan is a natural polysaccharide that is considered to be biocompatible, biodegradable and non-toxic. The polymer has been used in drug delivery applications for its positive charge, which allows for adhesion with and recognition of biological tissues via non-covalent interactions. In recent times, chitosan has been used for the preparation of graft copolymers with thermoresponsive polymers such as poly-N-vinylcaprolactam (PNVCL) and poly-N-isopropylamide (PNIPAM), allowing the combination of the biodegradability of the natural polymer with the ability to respond to changes in temperature. Due to the growing interest in the utilization of thermoresponsive polymers in the biological context, it is necessary to increase the knowledge of the key principles of thermoresponsivity in order to obtain comparable results between different studies or applications. In the present review, we provide an overview of the basic principles of thermoresponsivity, as well as a description of the main polysaccharides and thermoresponsive materials, with a special focus on chitosan and poly-N-Vinyl caprolactam (PNVCL) and their biomedical applications.

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Radical polymerization of N-vinylcaprolactam in benzene solutions in a wide conversion range

Cited by 13 publications

References 2 publications

Solution polymerization of N‐vinylcaprolactam in 1,4‐dioxane. Kinetic dependence on temperature, monomer, and initiator concentrations

Solution polymerization of N‐vinylcaprolactam in 1,4‐dioxane. Kinetic dependence on temperature, monomer, and initiator concentrations

Prediction of Chain Propagation Rate Constants of Polymerization Reactions in Aqueous NIPAM/BIS and VCL/BIS Systems

Chitosan-Based Biocompatible Copolymers for Thermoresponsive Drug Delivery Systems: On the Development of a Standardization System

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