Influence of polymer structure on the rheological behavior of hydroxypropylmethylcellulose-sodium carboxymethylcellulose dispersions

Alvarez‐Lorenzo, Carmen; Duro, R.J.; Gómez-Amoza, J.L.; Martínez‐Pacheco, Ramón; Souto, C.

doi:10.1007/s003960000463

Cited by 46 publications

(24 citation statements)

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“…From the charge density it can be deduced that a 1 wt % solution has a concentration of charges which is 33.6 mM; the overlap concentration is around 0.06 wt %. 23 CMC is fully ionized at pH 7 and is almost nonionic at pH 2. 22, 24 The cationic polymer, Quatrisoft LM200 (HMP + ) is a semiflexible polycation provided by Union Carbide Chemicals and Plastics Company, Inc., as the chloride salt of a N,N-dimethyl-N-dodecyl derivative of hydroxyethyl cellulose with a molar mass of ca.…”

Section: Methodsmentioning

confidence: 98%

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Mixed Systems of Hydrophobically Modified Polyelectrolytes: Controlling Rheology by Charge and Hydrophobe Stoichiometry and Interaction Strength

2005

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Rheology and phase separation were investigated for aqueous mixtures of two oppositely charged hydrophobically modified polyelectrolytes. The typical phase separation, normally seen for oppositely charged polymer mixtures, is dramatically reduced by the presence of hydrophobic modification, and phase separation is only detected close to the point of charge neutralization. While the two polyelectrolytes separately can give high viscosities and a gel-like behavior, a pronounced maximum in viscosity and storage modulus with the mixing ratio of the polyelectrolytes is observed; the maximum is located between the points of charge and hydrophobe stoichiometry and reflects a combination of hydrophobic and electrostatic association. Lowering the charge density of the anionic polymer leads to a strengthened association at first, but at lower charge densities there is a weakened association due to the onset of phase separation. The strength of the electrostatic interaction was modified by adding salt. Increased ionic strength can lead to phase separation and to increased or decreased viscosity depending on the polyelectrolyte mixing ratio.

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Section: Methodsmentioning

confidence: 98%

“…26 Its overlap concentration is around 2 g/dL. 23 The charges are located at the hydrophobic tails. A 1 wt % aqueous solution has a charge concentration of 2 mM.…”

Section: Methodsmentioning

confidence: 99%

Mixed Systems of Hydrophobically Modified Polyelectrolytes: Controlling Rheology by Charge and Hydrophobe Stoichiometry and Interaction Strength

2005

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“…Especificamente com relação à mistura CMC/AS 50/50, não foram observadas bandas características de ligações éster na região de 1700 e 1200 cm -1 , sugerindo a ausência de interações químicas fortes entre os dois polímeros. Aparentemente, as interações entre os dois componentes são do tipo hidrofóbico, como observado por Alvarez-Lorenso e colaboradores 28 para o sistema CMC/hidroxipropilmetilcelulose e Zhang 29 para a mistura CMC/hidroxietilcelulose.…”

Section: Teste De Germinação E Vigorunclassified

Preparação, caracterização e propriedades de filmes poliméricos com potencial aplicação no recobrimento de sementes

Oliveira¹,

Soldi²,

Coelho³

et al. 2009

Quím. Nova

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“…The weight average molecular weight is around 879 kDa. The overlap concentration is around 0.06 wt% [29,30].…”

Section: Methodsmentioning

confidence: 98%

Gelation of charged bio-nanocompartments induced by associative and non-associative polysaccharides

Antunes

Coppola

Rossi

et al. 2008

Colloids and Surfaces B: Biointerfaces

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a b s t r a c tVesicles composed of sodium oleate (NaO) and monoolein (MO) are adequate candidates for drug nanoencapsulation and controlled release due to their stability and perceived biocompatibility. The object of the present study is to design hydrogels based on those anionic vesicles and polymers of both non-associative and associative type. The selected macromolecules were k-carrageenan (KC), carboxymethyl cellulose (CMC) and hydrophobically modified carboxymethyl cellulose (HMCMC). While the polymer-vesicle association was probed by rheology, the influence of the polymer on the vesicle stability was monitored by cryo-TEM and calorimetric measurements.The effects of the polymer on the rheological properties of surfactant aggregate solutions clearly depend on the polymer type: the storage moduli of the polymer-vesicle mixtures, compared to the vesicles alone, increases around 2 orders of magnitude if the polymer is non-associative and 4 orders of magnitude if the macromolecule is of associative type.As the vesicles are added, the non-associative polymer networks tend to be disrupted, while the networks formed by associative polymer get more robust. These observations can be explained by fundamental changes in electrostatic/hydrophobic interactions: vesicles entrapped in KC networks convert the polysaccharide in a highly charged entity and favor high electrostatic repulsions between the chains; this encourages network collapse. The opposite picture is experienced in HMCMC systems, i.e., such network is stabilized by the presence of vesicles. This is ascribed to the enhanced hydrophobic association, compensating the electrostatic repulsions between vesicles and polymer chains.

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Influence of polymer structure on the rheological behavior of hydroxypropylmethylcellulose-sodium carboxymethylcellulose dispersions

Cited by 46 publications

References 0 publications

Mixed Systems of Hydrophobically Modified Polyelectrolytes: Controlling Rheology by Charge and Hydrophobe Stoichiometry and Interaction Strength

Mixed Systems of Hydrophobically Modified Polyelectrolytes: Controlling Rheology by Charge and Hydrophobe Stoichiometry and Interaction Strength

Preparação, caracterização e propriedades de filmes poliméricos com potencial aplicação no recobrimento de sementes

Gelation of charged bio-nanocompartments induced by associative and non-associative polysaccharides

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