Rheological properties of ethylcellulose latex

Gallardo, V.; Morales, María Encarnación; López-Viota, J.; Durán, J.D.G.; Ruíz, M. A.

doi:10.1002/app.24389

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…In the field of emulsions, ethyl cellulose can be used as an emulsifier, 9 incorporated into coatings [10][11] or used to elaborate microspheres notably for drug delivery applications. [12][13][14] The most developed procedure for the preparation of EC pseudo-latexes relies on either the emulsification/solvent evaporation (ESE) process [15][16] (which consists in the dissolution of EC in a suitable solvent, its subsequent emulsification into water phase containing suitable emulsifying agent, and finally the solvent evaporation) or miniemulsification. 17 A process based on nanoprecipitation has also been reported.…”

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confidence: 99%

New ethyl cellulose/acrylic hybrid latexes and coatings via miniemulsion polymerization

Chen¹,

Chu²,

Gauthier³

et al. 2010

J. Polym. Sci. A Polym. Chem.

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Ethyl cellulose (EC) was incorporated into copolymer latexes via miniemulsion polymerization. The effects of EC viscosity and EC content on droplet size, particle size and polymerization kinetics were investigated. The higher the EC content and viscosity, the larger the droplet size and the less stable the latex suspension. Small droplets that could be efficiently nucleated were formed for the lower-viscosity EC but the latex still showed limited colloidal stability. This was attributed to some phase-incompatibility between EC and the acrylic polymer. These stability issues were overcome by using an oil-soluble initiator and a cross-linker. The later enabled to physically entrap EC inside the polymer particles while the former allowed in situ grafting of the growing acrylic radicals to the EC backbone decreasing thereby the extent of phase separation. Thermal-mechanical analyses evidenced that the films obtained from the hybrid latexes displayed better properties than the EC-free latex films or the physical blends. This supports the hypothesis of formation of hybrid latexes that synergistically combine the properties of the acrylic matrix and the EC polymer. Interestingly, a significant increase of the elastic modulus was observed between 50-90°C. This mechanical reinforcement was tentatively attributed to the formation of a percolating EC-based hybrid phase.

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confidence: 99%

New ethyl cellulose/acrylic hybrid latexes and coatings via miniemulsion polymerization

Chen¹,

Chu²,

Gauthier³

et al. 2010

J. Polym. Sci. A Polym. Chem.

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“…High temperature also caused a change in particle shape. [11] Viriyaroj et al . in 2009 reported that carboxymethyl cellulose, methylcellulose and xanthan gum used as a suspending agent caused desirable rheological behavior Xanthan gum exhibits plastic or pseudoplastic flow and this behavior was possibly a result of shearing action on the long chain molecule of xanthan gum.…”

Section: Resultsmentioning

confidence: 99%

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent

Moghimipour¹,

Rezaee²,

Salimi³

et al. 2013

J Adv Pharm Technol Res

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Ciprofloxacin is a fluoroquinolone and is used against a broad spectrum of gram-negative and gram-positive bacteria. The aim of the study is to investigate the effect of structural vehicles and other formulating factors on physical stability and rheological behavior of ciprofloxacin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated. Then to achieve controlled flocculation, different concentrations of sodium chloride and calcium chloride were added. After choosing suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose (NaCMC), hydroxypropylmethylcellulose (HPMC) and Veegum were evaluated. Physical stability parameters such as sedimentation volume, the degree of flocculation and the ease of redispersion of the suspensions and growth of crystals were evaluated. After incorporation of structural vehicles, the rheological properties of formulations containing were also studied to find out their rheological behavior. According to the results, suspension containing glycerin (0.2% w/v) and sodium chloride (0.05% w/v) as wetting agent and flocculating agent, respectively, were the most stable formulations regarding their F and N. Microscopic observations showed the growth of crystals in ciprofloxacin suspension in formulation without excipients and the minimum amount of crystal growth was seen in suspension containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v). Rheological studies showed that almost all of the formulations had psuedoplastic behavior with different degree of thixotropy. The formulation containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v) was the most stable formulation. It may be concluded that by altering the amount ratios of formulation factors, the best rheological behavior and the most proper thixotropy may be achieved.

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“…The results showed that viscoelastic behavior was affected by temperature. High temperature also caused a change in particle shape (14). Moreria et al in 2010 investigated influence of oleic acid on the rheology and in vitro release of lumiracoxib from poloxamer gels.…”

Section: Discussionmentioning

confidence: 99%

Influence of Flocculating Agents and Structural Vehicles on the Physical Stability and Rheological Behavior of Nitrofurantoin Suspension

Moghimipour

Salimi

Rezaee³

et al. 2014

Jundishapur J Nat Pharm Prod

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Background:Nitrofurantoin is a nitrofuran antibiotic that has been used for treatment of urinary tract against positive and negative bacteria. Objectives: The aim of this study was to evaluate the effect of structural vehicles and flocculating agents on physical stability and rheological behavior of nitrofurantoin suspension. Materials and Methods: To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated and their particle sizes were determined using the sieve method. Then to achieve controlled flocculation, sodium citrate and aluminum chloride were added. After choosing the suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose and Veegum were evaluated individually and in combination. In addition, the effect of sorbitol on density of continuous phase and some physical stability parameters such as sedimentation volume, degree of flocculation and ease of redispersion of the suspensions were evaluated. After incorporation of structural vehicles, the rheological properties of formulations were also determined to find their flow behavior. Results: According to the results, glycerin (0.2%) and sodium citrate (0.3%) had the best effect on the suspension stability as wetting and flocculating agents, respectively. Rheological properties of formulations showed pseudoplastic behavior with some degree of thixotropy. Conclusions: In conclusion, the suspension containing Veegum 1%, sodium carboxy methyl cellulose 1%, glycerine 0.2%, sodium citrate 0.3% and sorbitol 20 % was chosen as the most physically stable formulation.

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Rheological properties of ethylcellulose latex

Cited by 4 publications

References 23 publications

New ethyl cellulose/acrylic hybrid latexes and coatings via miniemulsion polymerization

New ethyl cellulose/acrylic hybrid latexes and coatings via miniemulsion polymerization

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent

Influence of Flocculating Agents and Structural Vehicles on the Physical Stability and Rheological Behavior of Nitrofurantoin Suspension

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