Relationships between stress, strain, and molecular constitution of polymer networks. Comparison of theory with experiments

1982 ◽  
Vol 15 (3) ◽  
pp. 806-811 ◽  
Author(s):  
Burak Erman ◽  
Paul J. Flory
Keyword(s):  
Polymer Networks ◽  
Stress Strain ◽  
Molecular Constitution

Crosslinking, Filler, or Transition Constraint of Polymer Networks. II

1971 ◽  
Vol 44 (5) ◽  
pp. 1227-1248
Author(s):  
A. F. Blanchard
Keyword(s):  
Strain Hardening ◽  
Polymer Networks ◽  
Stress Strain ◽  
New Concepts ◽  
Filler Reinforcement ◽  
Hard Fraction ◽  
Rubber Filler

Abstract The theory of Part I is developed by application to filler reinforcement of NR and SBR. For unswollen but prestretched networks it quantifies entire stress-strain curves and applies new concepts of extensibility and strain hardening. Constraint of swelling is expressed by a constant Ø, termed linkage reinforcement, and by an effective hard fraction Cm per cm2 of compound. For rubber-filler swelling vc the modified Flory functions F(νc) in Part I need 3% correction.

Specific Solvent Effects in Swollen Polymer Networks

1974 ◽  
Vol 47 (5) ◽  
pp. 1151-1159 ◽  
Author(s):  
C. U. Yu ◽  
J. E. Mark
Keyword(s):  
Solvent Effects ◽  
Volume Fraction ◽  
Polymer Networks ◽  
Low Molecular Weight ◽  
Constant Composition ◽  
Stress Strain ◽  
Unperturbed Dimensions ◽  
Cohesive Energy Density ◽  
Octyl Acetate ◽  
Good Agreement

Abstract Stress—strain isotherms at 25° have been determined for uniaxially elongated poly(dimethylsiloxane) networks in the unswollen state and swollen consecutively with each of the following very dissimilar diluents : low molecular weight dimethylsiloxane fluid, n-hexadecane, 2,4-dichlorotoluene, and n-octyl acetate Five constant composition experiments were carried out, at values of the volume fraction ν2 of polymer of 1.00, 0.80, 0.60, 0.50, and 0.35. At ν2=0.80, the stress—strain isotherms were found to be independent of the nature of the diluent; at lower values of ν2, however, these isotherms were significantly different, thus demonstrating the existence of a “specific solvent effect” in swollen polymer networks. Interpretation of these data in terms of the statistical theory of rubberlike elasticity gave results in good agreement with previously reported specific solvent effects on the unperturbed dimensions of uncrosslinked poly (dimethylsiloxane) chains in solution. In neither case, however, do these effects correlate well with the cohesive energy density or dielectric of the diluent or solvent medium.

Stress-Strain Isotherms and Stress-Temperature Coefficients of Poly(Dimethylsiloxane) Networks in Compression

1975 ◽  
Vol 48 (2) ◽  
pp. 176-185 ◽  
Author(s):  
R. Y. S. Chen ◽  
C. U. Yu ◽  
J. E. Mark
Keyword(s):  
Statistical Theory ◽  
Temperature Coefficient ◽  
Polymer Networks ◽  
Temperature Measurements ◽  
Stress Strain ◽  
Unperturbed Dimensions ◽  
Temperature Coefficients ◽  
A Value ◽  
Good Agreement

Abstract Stress-strain isotherms at 30, 45, 60, 75, and 90°C have been determined for compressed, unswollen poly(dimethylsiloxane) networks which had been prepared either in the undiluted state or in solution. For these networks in compression, deviations of the dependence of stress on strain from that predicted by the statistical theory of rubberlike elasticity are much less than is the case for polymer networks in elongation. The present data nonetheless give a value for the temperature coefficient of the unperturbed dimensions of the network chains which is in good agreement with published results on networks of poly(dimethylsiloxane) in elongation. This agreement thus seems to validate the intentional disregard of such deviations in analyses of stress-temperature measurements.

Effect of Strain-Induced Crystallization on the Elastomeric Properties of Cis-1,4-Polybutadiene Networks

1978 ◽  
Vol 51 (2) ◽  
pp. 285-296 ◽  
Author(s):  
T-K. Su ◽  
J. E. Mark
Keyword(s):  
Polymer Network ◽  
Polymer Networks ◽  
Experimental Studies ◽  
Anomalous Behavior ◽  
Critical Examination ◽  
Complete Suppression ◽  
Stress Strain ◽  
Strain Induced Crystallization ◽  
Alternative Suggestion ◽  
Induced Crystallization

Abstract Polymer networks, when studied at very high elongations, frequency show anomalous stress-strain isotherms in that they exhibit values of the modulus or “reduced force” [ƒ*] which increase markedly with increasing elongation. Such isotherms depart appreciably from the form predicted by the molecular theories of rubberlike elasticity and from the Mooney—Rivlin representation adopted from phenomenological arguments as well. For this reason, the interpretation of the increase in [ƒ*] at high elongations has been of great interest for a considerable period of time. For several decades now, this behavior has generally been attributed to the limited extensibility of the network chains. Critical examination of various published results pertinent to this question, in conjunction with more definitive experimental studies reported recently, however, support the alternative suggestion that such atypical isotherms are due to strain-induced crystallization. One experiment particularly relevant to this issue is the study of the stress-strain isotherms of a polymer network as a function of temperature. Such experiments have been carried out on natural rubber, but the relatively poor thermal stability of this polymer and the extent to which its melting point is increased by elongation make it essentially impossible to study the high elongation stress-strain relationships for this polymer at a temperature sufficiently high to ensure complete suppression of strain-induced crystallinity. Similar experiments carried out on networks of a more suitable polymer, polyisobutylene, gave stress-strain isotherms showing the upturn in the reduced force at low temperature, but not at higher temperatures, thus strongly implicating strain-induced crystallization as the origin of this anomalous behavior. These experiments, however, suffered somewhat from the one shortcoming that the increase in temperature required to suppress the upturn in [ƒ*] also decreased the maximum extensibility of the network to below the elongation at which the upturn occurred at the lower temperatures.

Stress–strain behavior in polymer networks containing nonlocalized junctions

1977 ◽  
Vol 66 (8) ◽  
pp. 3363-3370 ◽  
Author(s):  
William W. Graessley ◽  
Dale S. Pearson
Keyword(s):  
Polymer Networks ◽  
Stress Strain ◽  
Strain Behavior

scholarly journals Stress–strain relation of entangled polymer networks

2000 ◽  
Vol 274 (1-3) ◽  
pp. 139-146 ◽  
Author(s):  
Gary S. Grest ◽  
Mathias Pütz ◽  
Ralf Everaers ◽  
Kurt Kremer
Keyword(s):  
Polymer Networks ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Entangled Polymer
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