Stress-strain isotherms for polymer networks at very high elongations

1979 ◽  
Vol 19 (4) ◽  
pp. 254-259 ◽  
Author(s):  
James E. Mark
Keyword(s):  
Polymer Networks ◽  
Stress Strain ◽  
Very High

Determination of stress-strain characteristics at very high strain rates

1970 ◽  
Vol 10 (9) ◽  
pp. 370-376 ◽  
Author(s):  
C. K. H. Dharan ◽  
F. E. Hauser
Keyword(s):  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Very High

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.

Stress-Strain Testing of Rubber at High Rates of Elongation

1963 ◽  
Vol 36 (1) ◽  
pp. 28-49
Author(s):  
Mark L. Dannis
Keyword(s):  
Tensile Strength ◽  
Time Scale ◽  
High Speed ◽  
Dynamic Properties ◽  
Stress Strain ◽  
High Frequencies ◽  
Apparent Modulus ◽  
Strain Testing ◽  
Considerable Body ◽  
Very High

Abstract It is well known that the properties of rubbery materials depend upon the speed or rate at which they are tested or used. A considerable body of work has shown that the dynamic properties of rubber change with the time scale of the test and, in particular, at very short times or at very fast rates, the properties approach those of plastics, i.e., high modulus and low elongation. These dynamic properties are measured by oscillation methods, usually at small strains. In contrast to this class of information, where the material is rarely strained to failure, one can also strain rubbers unidirectionally to failure at strain rates that correspond to the high frequencies of dynamic measurements. In linear extension experiments, as the rate of stretching increases tensile strength rises, elongation drops, apparent modulus increases, and relaxation losses may go up or down depending upon the particular rubber and the time scale of the phenomenon that is being investigated. Extrapolating the change in tensile strength with rate of testing suggests that tensile strength as we know it should change drastically when measured at very high rates of speed. That is, since the viscoelastic properties of rubber are time dependent, and also dependent upon the speed at which they are tested, the tensile properties of rubbers measured at room conditions with the ordinary Scott or Instron machines probably do not have the same values as at the speeds and frequencies that might be encountered in such situations as tire wear. Hence, we should like to measure the properties of rubbers at very high rates of speed, presumably comparable to those encountered in tire tread wear, in order to find out how much properties do change as the speed of test is increased. In order to measure stress-strain properties at rates of elongation comparable to those we believe exist in tire tread usage, we had to develop a small high speed tensile machine. The purpose of this paper is to describe that machine and some results obtained with it.

scholarly journals Analysis of automotive fixing plate drawing process

Mechanik ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1075-1077
Author(s):  
Jarosław Świtacz ◽  
Jarosław Bartnicki
Keyword(s):  
Effective Stress ◽  
Numerical Results ◽  
Numerical Analyses ◽  
Drawing Process ◽  
Stress Strain ◽  
Good Convergence ◽  
Real Process ◽  
Very High

The paper deals with the drawing process of automotive fixing plates realized in progressive tools. Numerical analyses by means of FEM were done for chosen parts of the process. The distributions of effective stress, strain and load parameters were analyzed for realization of real process in practice. Good convergence between numerical results and final parts ones confirms very high applicability of FEM tools in these kinds of processes calculations.

Interpenetrating polymer networks formed by cyanate esters and phenylethynyl-terminated imides

2016 ◽  
Vol 29 (5) ◽  
pp. 556-568 ◽  
Author(s):  
Christoph Meier ◽  
Patricia P Parlevliet ◽  
Manfred Döring
Keyword(s):  
Polymer Networks ◽  
Covalent Bond ◽  
High Heat ◽  
Interpenetrating Polymer Networks ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermal Gravimetry ◽  
Pendent Group ◽  
Very High ◽  
End Group

An oligomeric phenylethynyl-terminated imide (PETI) has been formulated with a cyanate ester (CE) with and without the addition of a compatibilizer 2,2′-diallylbisphenol A (DABPA) forming interpenetrating polymer networks (IPNs). Modulated differential scanning calorimetry (mDSC) was used to monitor the curing of the resin mixtures. The formation of various resulting IPNs was verified using mDSC, dynamical mechanical thermoanalysis (DMTA), thermal gravimetry analysis and scanning electron microscopy. Furthermore, it could be shown by mDSC and DMTA that a covalent bond of the separated CE and PETI networks could be achieved by the addition of DABPA. In this regard, a reaction mechanism is proposed for the cross-linking reaction between the allylic pendent group of DABPA and the phenylethynyl end-group of the PETI resin. The cured resin specimens showed to have very high heat resistance and very high glass transition temperatures up to 330°C.

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.

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