Some properties of water‐soluble hydroxyalkyl celluloses and their derivatives

Klug, E

doi:10.1002/polc.5070360137

Cited by 93 publications

(40 citation statements)

References 11 publications

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“…5,11,12 A so-called cloud point T c , at which the optical turbidity of such a binary mixture rises sharply on heating, is situated around 40 1C with regard to isotropic aqueous HPC solutions, but it is rather lowered at higher HPC concentrations, leading to the mesophase formation. This phase-separation behavior of aqueous HPC solutions would also be affected by addition of imidazolium salts and the changing manner should depend on the ion species and concentration of the used one, as in the case of the previous HPC/water system containing conventional inorganic salts.…”

Section: Lcst-type Phase-separation Behaviormentioning

confidence: 99%

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Addition effects of imidazolium salts on mesophase structure and optical properties of concentrated hydroxypropyl cellulose aqueous solutions

Chiba

Ito

Nishio

2010

Polym J

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Addition effects of N-alkyl-substituted methylimidazolium salts ([CnMim][X]) on the mesophase structure and lower critical solution temperature (LCST)-type phase-separation behavior of concentrated hydroxypropyl cellulose (HPC) aqueous solutions were investigated mainly by spectrophotometry. In the cholesteric mesophase formation, at concentrations of more than 50 wt% HPC, helical pitch (P) was confirmed to shift upward according to the chaotropic strength of X -, for example, in a manner satisfying the order of Cl À oBr À oNO 3 À oI À . Organocations generally elevated P relative to the nonionic reference, the effectiveness being pronounced in the order ofWith regard to LCST behavior, imidazolium additives raised the cloud point (T c ) in the isotropic solutions of p40 wt% HPC, whereas the T c value of mesomorphic solutions was prone to be lowered by the addition. Discussion of these observations took into consideration the differences in the N-alkyl structure and amphiphilic nature between cationic imidazolium varieties, as well as the difference in the chaotropic strength between the counter anions. It was also exemplified preliminarily that this kind of salt-containing lyotropic system of HPC exercised an electro-optical function when coupled with an electric circuit.

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Section: Lcst-type Phase-separation Behaviormentioning

confidence: 99%

“…50-70 wt%. 5,10 Aqueous HPC solutions also show a phase-separation behavior with the lower critical solution temperature (LCST) usually located at o45 1C, 5,11,12 and therefore they become turbid on heating.…”

Section: Introductionmentioning

confidence: 99%

Addition effects of imidazolium salts on mesophase structure and optical properties of concentrated hydroxypropyl cellulose aqueous solutions

Chiba

Ito

Nishio

2010

Polym J

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“…Although cellulosic derivatives [14][15] were the first thermothickeners to be used in aqueous media, thermoresponsive systems have been widely diversified during the last two decades [4,7,16]. They are generally designed on the basis of block or graft architectures containing hydrophilic and water-soluble moieties alternating with responsive blocks or grafts characterized by a Lower Critical Solution Temperature (LCST) in the range of application.…”

Section: Introductionmentioning

confidence: 99%

Influence of topology of LCST-based graft copolymers on responsive assembling in aqueous media

Guo

Brûlet

Rajamohanan

et al. 2015

Polymer

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This work, based on structure/properties relationships of associating polymers, aims to investigate the role of topology in the self-assembling behavior of responsive graft copolymers. For that purpose, two graft copolymers with inverse topologies were prepared with similar amounts of water-soluble chains (poly(N,N-dimethylacrylamide) = PDMA) and LCST polymer chains (poly(N-isopropylacrylamide) = PNIPA). In pure water, and above 3 wt%, PNIPA-g-PDMA and PDMA-g-PNIPA exhibit very similar macroscopic properties with a sol/gel transition above 35 °C related to the microphase separation of PNIPA sequences. From complementary experiments, performed by DSC, 1 H NMR and small angle neutron scattering, we show that the phase transition of PNIPA is more abrupt when NIPA units are located within the backbone, compared to side-chains. Nevertheless, well above their transition temperature, the two copolymers display very similar bicontinuous structures where PNIPA sequences self aggregate into concentrated percolating domains (about 70 wt% at 60 °C) characterized by a frozen dynamics. On the other hand, when salt or surfactant molecules are added into unentangled semi-dilute aqueous solution, the PNIPA-g-PDMA sample does not percolate anymore above the transition temperature while PDMA-g-PNIPA still demonstrate thermothickening properties that are correlated to the ability of water-soluble PDMA chains to bridge PNIPA aggregates.

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“…These properties include self-assembly of the polymer , specific interactions with low-and high-molecular mass compounds (Uraki et al 2000), and reduced lower critical solution temperature (LCST). HPC exhibits an LCST of more than 40°C (Klug 1971), while HPC-L has an LCST of around body temperature. Thus, HPC-L is a body temperaturesensitive polymer.…”

Section: Introductionmentioning

confidence: 99%

Body temperature-responsive gels derived from hydroxypropylcellulose bearing lignin II: adsorption and release behavior

et al. 2006

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The lower critical solution temperature (LCST) of hydroxypropylcellulose bearing lignin (HPC-L) prepared from unbleached pulp depends on the amount of residual lignin. An HPC-L gel having thermal properties reflective of original HPC-L was prepared using ethyleneglycol diglycidylether as a crosslinker, as previously reported [Uraki et al. (2004) Carbohydr. Polym. 58:123 -130], and the volume transition temperature was detected as an endothermic peak by differential scanning calorimetry (DSC). The adsorption and release behavior of the guest molecules to/from this gel was then examined. When the adsorption of cationic and anionic guests was compared, cationic methylene blue (MB) was adsorbed in larger amounts than anionic methyl orange (MO). In addition, MB adsorption into the HPC-L gel was greater than MB adsorption into the HPC gel prepared from commercially available HPC. This suggests that residual lignin affects the adsorption of organic dyes. Significant differences were not observed with respect to the release of MB from HPC-L at 38°C and lower temperatures. In the adsorption of surfactants, marked adsorption at around the critical micelle concentration of the ionic surfactants and gel swelling were observed. Such swelling did not occur in the aqueous nonionic surfactant solution, although the nonionic surfactant was adsorbed into the gel. Gel swelling may have been caused by the electrostatic repulsion of the ionic surfactants adsorbed onto the polymer chains within the gel structure.

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Some properties of water‐soluble hydroxyalkyl celluloses and their derivatives

Cited by 93 publications

References 11 publications

Addition effects of imidazolium salts on mesophase structure and optical properties of concentrated hydroxypropyl cellulose aqueous solutions

Addition effects of imidazolium salts on mesophase structure and optical properties of concentrated hydroxypropyl cellulose aqueous solutions

Influence of topology of LCST-based graft copolymers on responsive assembling in aqueous media

Body temperature-responsive gels derived from hydroxypropylcellulose bearing lignin II: adsorption and release behavior

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