Hydrophobic water‐soluble polymers, 1. Dilute solution properties of poly(1‐vinyl‐2‐piperidone) and poly(<i>N</i>‐vinylcaprolactam)

Eisele, Michael; Burchard, Walther

doi:10.1002/macp.1990.021910114

Cited by 57 publications

(37 citation statements)

References 23 publications

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“…Among temperature‐sensitive polymers, poly ( N ‐isopropylacrylamide) (PNIPAM) is probably the most popular one and nowadays increasing attention has been paid to the PNIPAM‐based microgels 4–7. There is another thermoresponsive polymer, poly( N ‐vinylcaprolactam) (PVCL),8, 9 which is a relatively new type of nonionic polymer with phase transition in the region of physiological temperature (31–38 °C) 10. PVCL presents a very interesting property; it is biocompatible 11.…”

Section: Introductionmentioning

confidence: 99%

N‐vinylcaprolactam‐based microgels: Synthesis and characterization

Imaz

Forcada

2008

J. Polym. Sci. A Polym. Chem.

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Poly(N‐vinylcaprolactam) (PVCL) is well known for its thermoresponsive behavior in aqueous solutions. PVCL combines useful and important properties; it is biocompatible polymer with the phase transition in the region of physiological temperature (32–38 °C). This combination of properties allows consideration of PVCL as a material for design biomedical devices and use in drug delivery systems. In this work, PVCL based temperature‐sensitive crosslinked particles (microgels) were synthesized in a batch reactor to analyze the effect of the crosslinker, initiator, surfactant, temperature, and VCL concentration on polymerization process and final microgels characteristics. The mean particle diameters at different temperatures and the volume phase‐transition temperature of the final product were analyzed. To obtain information about the inner structure of microgel particles, semicontinuous polymerizations were carried out and the evolution of the hydrodynamic average particle diameters at different temperatures of the microgel synthesized was investigated. In the case of microgel particles obtained in a batch reactor the size and the swelling‐de‐swelling behavior as a function of the temperature of the medium can be tuned by modulating the reaction variables. When the microgel particles were synthesized in a semibatch reactor different swelling‐de‐swelling behaviors were observed depending on particles inner structure. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2510–2524, 2008

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Section: Introductionmentioning

confidence: 99%

N‐vinylcaprolactam‐based microgels: Synthesis and characterization

Imaz

Forcada

2008

J. Polym. Sci. A Polym. Chem.

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“…Viscosity average molecular weights (M v ) are determined from the intrinsic viscosity employing the Mark- [15] The intrinsic viscosity was measured with an Ubbelohde-type viscosity meter at 25 8C using water as solvent.…”

Section: Methods Of Analysismentioning

confidence: 99%

Thermo‐Responsive Organic/Inorganic Hybrid Hydrogels based on Poly(N‐vinylcaprolactam)

Loos

Verbrugghe

Goethals

et al. 2003

Macro Chemistry & Physics

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A new type of ‘intelligent’ hydrogels has been developed in the form of organic/inorganic hybrid materials by making use of the sol‐gel technology. Poly(N‐vinylcaprolactam) (PVCL) has been incorporated in these materials for its thermo‐responsive properties. The synthesis of the hybrid hydrogels was achieved by the in situ formation of an inorganic silica phase in the presence of an aqueous solution of high molecular weight PVCL. This methodology results in the preparation of micro‐heterogeneous systems in which silica particles of nanometer dimensions act as physical cross‐links for the PVCL molecules. Hydrogen bonds between the remaining non‐condensed silanol groups and the PVCL carbonyl functions, together with physical entanglements, are responsible for the strong interactions between the organic and inorganic phases. Stress‐strain tests on highly swollen materials demonstrated that the unique structure of these thermo‐responsive hybrid hydrogels improves the mechanical stability to a great extent as compared to conventional hydrogels. Transmission measurements demonstrate that the presence of the inorganic phase does not influence the cloud point temperatures of PVCL significantly. On the other hand, the response of the reinforced hybrid hydrogels to temperature becomes less pronounced for increasing silica fractions. The reversibility of the swelling/deswelling process has been demonstrated by swelling experiments as a function of temperature. PVCL/SiO2 hybrid hydrogels.magnified imagePVCL/SiO2 hybrid hydrogels.

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“…Thus in good solvents, where A 2 O0, we expect c!0.5. For PVCL in water at room temperature, small positive virial coefficients are reported [20,33], corresponding to 0.49!c!0.50. Furthermore, the MarkHouwink expression [h]ZkM a for the intrinsic viscosity [33] yields aZ0.69, which would be interpreted to mean that water is a moderately good solvent.…”

Section: A2 Swelling Characterizationmentioning

confidence: 99%

“…For PVCL in water at room temperature, small positive virial coefficients are reported [20,33], corresponding to 0.49!c!0.50. Furthermore, the MarkHouwink expression [h]ZkM a for the intrinsic viscosity [33] yields aZ0.69, which would be interpreted to mean that water is a moderately good solvent. We therefore choose cZ0.5, even though other authors [18] back-calculate cZ0.52, and even higher values of c have appeared [34].…”

Section: A2 Swelling Characterizationmentioning

confidence: 99%