Effect of the reference chain dimensions in the molecular theory of viscoelastic behavior of polymer networks

Ilavský, M.; Hasa, J.; Havlíček, Ivan

doi:10.1002/pol.1972.160100913

Cited by 21 publications

(9 citation statements)

References 15 publications

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“…It can be seen that the increase of the degree of cross-linking results in smoother gel collapse. Comparison of curves 1, 4, and 5 shows that the increase of the concentration of monomers at the preparation conditions which results in appearance of additional topological entanglements (refs 17 and 18) also leads to smoothening of the collapse. Thus, both the increase of the content of chemical cross-links and of topological entanglement affect the collapse in the same manner.…”

Section: Resultsmentioning

confidence: 97%

Collapse of polyelectrolyte networks induced by their interaction with oppositely charged surfactants

Khokhlov¹,

Kramarenko²,

et al. 1992

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The interaction of charged surfactants with oppositely charged polyelectrolyte networks has been investigated. The effective absorption of the surfactant ions by charged gel is observed. The surfactantnetwork complex formation results in gel collapse. The influence of charge density and mobility, ionic strength, and network topology on complex formation has been studied. It has been shown that the surfactant ions in charged gel form micelle-like aggregates. Due to this fact the surfactant-network complexes are effective absorbers for hydrophobic organic substances.

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Section: Resultsmentioning

confidence: 97%

Collapse of polyelectrolyte networks induced by their interaction with oppositely charged surfactants

Khokhlov¹,

Kramarenko²,

et al. 1992

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“…These calculated curves are given in Figure 10, together with the theoretical prediction for crosslinked networks with an energy elastic component such as EPDM. 27 In addition, G'(0,435) is tabulated in column 3 of Table 11. Strangely enough, the variation of G'(0,T) with temperature is very much dependent on the cure level.…”

Section: Influence Of Degree Of Crosslinking On Linear Thermoviscoelamentioning

confidence: 99%

Linear thermoviscoelasticity and characterization of noncrystalline EPDM rubber networks

Scholtens

1984

J. Polym. Sci. Polym. Phys. Ed.

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An experimental study has been made to specify how the time‐temperature superposition and the linear viscoelastic characteristics vary with the degree of crosslinking for a broad class of noncrystalline peroxide‐cured EPDM networks. A new, very sensitive method is applied to determine the horizontal and vertical shift functions in an independent way. All uncrosslinked samples are thermoelasticoviscously simple with horizontal shift functions aT of the WLF type and vertical shift functions almost independent of temperature, in agreement with recent theoretical understanding. Upon crosslinking, these materials become thermoviscoelastically complex networks, but superposition can still be accomplished by assuming different temperature dependences for the relaxational strength and the equilibrium modulus. The aT functions can be taken independent of the degree of crosslinking. The vertical shift functions bT for the relaxational strength vary with the degree of crosslinking between theoretical predictions for uncrosslinked and perfectly crosslinked EPDM networks. The equilibrium moduli of the lightly cured networks decreases with increasing temperature, which is ascribed to the presence of interchain associations between ethylene sequences in the trans state. Upon further crosslinking, these effects gradually vanish and eventually the networks can be described as viscoelastically simple with an energy elastic contribution due to the ethylene trans‐gauche transitions. The linear viscoelastic characteristics, namely the storage and loss moduli and compliances and phase‐angle master curves and the relaxation and retardation spectra are discussed as a function of the degree of crosslinking. A sol/gel analysis and equilibrium swelling measurements complete the experimental characterization of three familes of five EPDM networks each.

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“…The optical relaxation function (strain-optical function) B(t) = An(t)/e = 6 (t) to/2z d (20 = 546.1 nm is the wavelength of light, d is the sample thickness) was determined from the time dependence of optical retardation 6(t); the stress-optical function C(t) = B(t)/E(t) was also calculated. From the molecular theory of photoelastic behaviour [13,14] which allows for the fact that conditions of (2) the logarithms of their absolute values are plotted in Figure 2.…”

Section: Methodsmentioning

confidence: 99%

“…The superimposed curves of mechanical and optical functions Ep(t), Bp(t) and Cp(t) to To (= 230 k for PDMA and 329 K for PHEMA) were constructed using corresponding curves measured at experimental temperatures T by applying the time-temperature superposition according to relations [13,14] …”

Section: Temperature and Time Behaviour Of Homopolymersmentioning

confidence: 99%

“…Modification of Rouse's molecular theory for polymer networks involving the effect of the reference state of network [13] has led to a conclusion that the configurational rearrangement of an elastically active network chain (EANC) by applying an external force gives the relaxation spectrum H in the form H(r) --= (2~c) -1 v,a <a~d> 312 (P Co ~ kT/6) v2 r-1/2 = Ho ~-l/2 (4) where P is the degree of polymerization of EANC, via is the number of chains in the dry isotropic state, Co is the monomeric frictional coefficient, k is the Boltzmann constant, <ce~a> = ~ia/~ is the dialation factor (#a being the mean square end-to-end EANC distance in the isotropic state), and v is the relaxation time. If the network volume is independent of deformation, we have from the phenomenological theory of linear viscoelastic behaviour [2] and from Equation (4) …”

Section: Ep(t) = E(t)(toit)(otolot) '"mentioning

confidence: 99%

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The thermorheological complexity of photoelastic behaviour of 2-hydroxyethyl methacrylate — dodecyl methacrylate copolymers

Hrouz

Havlíček

Ilavský

1987

Colloid & Polymer Sci

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The viscoelastic photoelastic behaviour of networks of 2-hydroxyethyl methacrylate-dodecyl methacrylate (DMA) copolymers in the main transition and rubberlike region was investigated. With increasing DMA content, photoelastic functions are quickly shifted to lower temperatures or shorter times; a detailed course of the functions suggests heterogeneity of the copolymers. Due to the existence of long side chains, optical function of all samples change the sign from positive to negative with increasing temperature. While the temperature dependences of the moduli of copolymers can be described by the two-phase Takayanagi model, the temperature dependences of optical functions cannot be described by using this model. It has been found, however, that the tempeature and time dependences of photoelastic functions can be described semiquantitatively by a three-phase model with a hypothetical statistical copolymer as the third component. The high values of the volume fraction of the hypothetical statistical copolymer found for the individual samples, suggest a considerable miscibility and a strong influence of the interphase boundary on the photoelastic behaviour of the copolymers.

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Effect of the reference chain dimensions in the molecular theory of viscoelastic behavior of polymer networks

Cited by 21 publications

References 15 publications

Collapse of polyelectrolyte networks induced by their interaction with oppositely charged surfactants

Collapse of polyelectrolyte networks induced by their interaction with oppositely charged surfactants

Linear thermoviscoelasticity and characterization of noncrystalline EPDM rubber networks

The thermorheological complexity of photoelastic behaviour of 2-hydroxyethyl methacrylate — dodecyl methacrylate copolymers

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