Rheological and micro structural studies of methylcellulose solutions in N,N-dimethylformamide for preparation of extruded beads: controlled urea release

Singh, Reeti; Kundu, Patit Paban

doi:10.1007/s00397-017-1066-4

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…Figure is the optical image, showing an amalgamation of two beads to form a single bead (10 m). On the other hand, the amalgamation of beads to form larger bead was not observed in MC‐DMF gels under optical microscope and SEM . In comparison to MC aqueous system, the gelation of MC‐DMF is due to polymer conformational changes during cooling.…”

Section: Resultsmentioning

confidence: 88%

“…Therefore, the internal energy is decreased resulting in the drop in entropy, and thus, the kinetic energy of beads may not be sufficient to collide to form the larger bead. So, the combination of beads manifests the formation of rods, leading to the formation of further strong gel network .…”

Section: Resultsmentioning

confidence: 99%

“…Earlier, many studies have been conducted on the gel properties of MC organic/aqueous system, such as the gel temperature and gel strength using a dynamical mechanical analyzer (under shear and compression mode). These properties are found to be functions of the molecular weight, degree of methyl substitution, concentration, and the presence of additives . Lott et al observed the formation of the fibrous structure of aqueous MC gels under cryogenic transmission electron microscopy that was further confirmed by small‐angle neutron scattering studies .…”

Section: Introductionmentioning

confidence: 92%

“…The inverse‐gelation phenomenon is rather considered to be hydrophobic and hydrophilic associations . During heating, the MC molecules get aggregated to form junction zones, micelles, helixes, beads, rods, core‑shell, and cage‐like structures . However, these conformations are schematically represented by Tanaka.…”

Section: Introductionmentioning

confidence: 99%

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Studies on rheological, thermal, and morphological properties of methylcellulose gel in aqueous medium

Singh¹,

Kundu

2019

Polymer Engineering & Sci

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The rheological, morphological, and thermal behavior of aqueous methylcellulose (MC) gels was investigated by optical microscope, dynamic mechanical analyzer (DMA), and differential scanning calorimeter. The double crossover between the storage modulus and loss modulus during the frequency scan in DMA suggests the transition from gel to sol state. These gel networks are comprised of bead-rod structures, which is visible under the optical microscope. Furthermore, the degelation mechanism of gels comprises of the thermodynamic viable bead burst phenomenon. The reheated samples of MC under dynamic compression show partial irreversibility of the MC aqueous system, indicating the possible presence of weakly coupled random coils and helix. The phenomenon of turbidity of MC aqueous gels is discussed with the help of a large bead model, in which the small-sized beads present in aqueous solution collide with each other to form large beads. FIG. 4. (a) Plot between storage and loss modulus as a function of frequency Hz for 5 wt% MC-4000 gel at 50 C. (b) Plot between storage and loss modulus as a function of frequency Hz for 5 wt% MC-1500 gel at 50 C. (c) Plot between storage and loss modulus as a function of frequency Hz for 5 wt% MC-4000 gel at 80 C. (d) Plot between storage and loss modulus as a function of frequency Hz for 5 wt% MC-1500 gel at 80 C. (e) Plot between storage and loss modulus as a function of frequency Hz for 5 wt% MC-25 gel at 80 C. [Color figure can be viewed at wileyonlinelibrary.com]

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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