Cascade model for coupled two‐component polymer gels

Mao, Ching-Feng; Chen, Jia-Chin

doi:10.1002/app.22641

Cited by 7 publications

(9 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to the above features, two questions arise regarding these high functionalities. First, the best‐fit parameters are in disagreement with those obtained from the concentration dependence of gel modulus 8. For example, the values of functionality ( f LBG = 500 and f XG = 300) are much higher than those obtained from the concentration dependence data ( f LBG = 30 and f XG = 50).…”

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 81%

“…In our previous study, the cascade model for a coupled two‐component polymer gel was developed based on a simple interaction scheme8: The junction zones of gel networks are formed via the interaction between the crosslinking sites of two different polymers: The two polymers of molecular weights M A and M B carrying functionalities f A and f B are mixed with a concentration ratio r (= C B / C A ). Thus, the conversions of the two kinds of crosslinking sites α A and α B can be obtained from the equilibrium equation: where K is the equilibrium constant.…”

Section: Cascade Modelmentioning

confidence: 99%

“…One of the characteristics of a gel is its elasticity, which can be measured as gel modulus using a rheometer. In the cascade model, the gel modulus G for a two‐component polymer gel can be expressed in terms of the algebraic sum of the number of elastic active chains for each individual component8: where a is the front factor, an empirical parameter representing the deviations from the ideal rubber elasticity. For an ideal rubber, eq.…”

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 99%

“…Goycoolea et al24 have measured the concentration dependence and temperature dependence of gel modulus for the galactomannan/xanthan system and the glucomannan/xanthan system at different concentration ratios. In our previous study,8 we have analyzed the concentration dependence of gel modulus for these gels and have shown that the cascade model can be successfully applied to describe these data. In this study, the temperature dependence data are analyzed using the aforementioned temperature dependence equations.…”

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 99%

“…The gel network generated in this way is called a coupled network 7. In our previous article,8 we discussed the gel modulus and the gel point of a coupled network. We assumed that the interaction between the two components follows a pairwise reaction at equilibrium and the network structure is described by a cascade model 9.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Temperature dependence of gel properties of two‐component physical gels

Mao

2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The cascade model for mixed gels developed by the author in a previous work is extended to describe the temperature-dependent gel properties. The equilibrium constant of the association between component polymers is assumed to depend on temperature via a van't Hoff-type equation. The temperature variation of the network structure and gel modulus is presented and discussed at different parameters such as enthalpy change per crosslink ⌬H°, entropy change per crosslink ⌬S°, functionality ratio s, and concentration ratio r. It is demonstrated that the model agrees reasonably well with the experimental data obtained from the rheological gelling for galactomannan/xanthan and glucomannan/xanthan mixed gels. However, the resulting model parameters are not consistent with those obtained from the concentration dependence study. A further investigation on the calorimetric thermogram of the glucomannan/xanthan mixed gel reveals that the gelling process involves an association reaction followed by a structural rearrangement, which is beyond the scope of this work. Finally, the cascade model is shown to be consistent with the Eldridge-Ferry equation. It is also demonstrated that the solgel behavior of the galactomannan/xanthan mixed gel follows the Eldridge-Ferry relationship, but the calculated melting enthalpy is composition-dependent, contrary to the assumption made in the cascade model. This discrepancy is due to the self-association of xanthan when xanthan is present in excess amounts.

show abstract

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 81%

Section: Cascade Modelmentioning

confidence: 99%

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 99%

Section: Temperature Dependence Of Gel Modulusmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Temperature dependence of gel properties of two‐component physical gels

Mao

2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

show abstract

Different Gelation and Self‐Sorting Properties of Two Isomeric Polyamides Owing to the Parallel versus Anti‐Parallel Alignment of Backbone Dipoles

Leung

Chow

2017

Chemistry A European J

View full text Add to dashboard Cite

Two isomeric bottlebrush polyamides P-1 and A-1, with the same repeating monomer dipole units aligned along the polymer backbone in pseudo-parallel and pseudo-antiparallel fashion, respectively, were synthesized and characterized. Both polymers can form thermoreversible gels with aromatic solvents but P-1 was found to show inferior gelation strength compared with that of A-1. Furthermore, despite their close structural resemblance, a 1:1 mixture of the P-1 and A-1 polymers was shown to exhibit self-sorting in the gel state. Gel formation was found to be a kinetically trapped process through hydrogen bonding, π-π stacking interactions, and side chain interdigitation. The different gelation and self-sorting properties can be explained by the local dipole-dipole interactions originating from the different modes of backbone dipole alignment. In single gel systems, the antiparallel-aligned dipoles in A-1 facilitated a more compact molecular packing owing to the enthalpically more favorable polymer chain association. On the other hand, the parallel-aligned dipoles in P-1 gave rise to a less stable head-to-head packing, which had difficulties to convert to the more stable head-to-tail packing in a kinetically trapped environment. In the mixed gel system, it is the unfavorable hetero-polymer mismatch dipole-dipole interaction that inhibited the mixing of the A-1 and P-1 polymers and led to self-sorting.

show abstract

Self‐ and cross‐associations in two‐component mixed polymer gels

Mao

2007

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

The gel properties of two‐component mixed polymer gels are investigated using a cascade model, which assumes that the gel network is formed via the self‐association of one of the two components and the cross‐association of the two components. The effects of the model parameters, such as the equilibrium constants and the functionalities for cross‐associations and self‐associations, on the composition dependence of the modulus and gel point curves are examined to elucidate the contribution of self‐associations to the gel network. The results show that the characteristics of self‐associations become pronounced when the equilibrium constant or the functionality for self‐associations is comparable to that for cross‐associations. The model is applied to analyze the critical gelling concentration data for xanthan/locust bean gum mixed gels, which shows significant self‐associations at high xanthan compositions. The resulting model curves agree well with the experimental data at all temperatures. The analysis of the temperature dependence of the best‐fit equilibrium constant yields values of enthalpy change that are consistent with previous findings. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 80–91, 2008

show abstract

Cascade model for coupled two‐component polymer gels

Cited by 7 publications

References 36 publications

Temperature dependence of gel properties of two‐component physical gels

Temperature dependence of gel properties of two‐component physical gels

Different Gelation and Self‐Sorting Properties of Two Isomeric Polyamides Owing to the Parallel versus Anti‐Parallel Alignment of Backbone Dipoles

Self‐ and cross‐associations in two‐component mixed polymer gels

Contact Info

Product

Resources

About