Chemorheological response of elastomers at elevated temperatures: Experiments and simulations

Shaw, John A.; Jones, Alison Snow; Wineman, Alan S.

doi:10.1016/j.jmps.2005.07.004

Cited by 91 publications

(109 citation statements)

References 29 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…Its variation would be similar to that observed in experiments on rubber strips in fixed uniaxial extension (see Jones [6] and Shaw et al [9]). For a constant uniaxial stretch ratio, the force required to hold the strip increased at first with temperature T(t) due to entropic stiffening, but then reached a maximum and decreased as the response became dominated by the decrease of b (1) (t) due to scission while T > T cr .…”

Section: Response During Scission and Re-crosslinkingsupporting

confidence: 85%

“…The underlying constitutive framework was developed by Wineman and Rajagopal [12] and Rajagopal and Wineman [7] for deformation induced scission and crosslinking. For a detailed discussion of the subsequent application of this framework to thermally induced scission and crosslinking, see Jones [6] and Shaw et al [9].…”

Section: Constitutive Equationmentioning

confidence: 99%

“…Tobolsky also proposed a constitutive equation for uniaxial stretch at constant temperature accounting for two material networks, the remainder of the original material molecular network and a newly formed network. An extension of this constitutive equation to arbitrary deformation and temperature histories to account for continuous destruction and growth of material network has been proposed and studied by Jones [6] and Shaw et al [9].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Thermally Induced Chemorheological Changes on the Inflation of Spherical Elastomeric Membranes

Wineman

Shaw

2005

J Elasticity

View full text Add to dashboard Cite

When an elastomeric material is deformed and subjected to temperatures above some chemorheological value T cr (near 100-C for natural rubber), its macromolecular structure undergoes time and temperature dependent chemical changes. The process continues until the temperature decreases below T cr . Compared to the virgin material, the new material system has modified properties (often a reduced stiffness) and permanent set on removal of the applied load. A recently proposed constitutive theory is used to study the influence of chemorheological changes on the inflation of an initially isotropic spherical rubber membrane. The membrane is inflated while at a temperature below T cr . We then look at the pressure response assuming the sphere's radius is held fixed while the temperature is increased above T cr for a period of time and then returned to its original value. The inflation pressure during this process is expressed in terms of the temperature, representing entropic stiffening of the elastomer, and a time dependent property that represents the kinetics of the chemorheological change in the elastomer. When the membrane has been returned to its original temperature, it is shown to have a permanent set and a modified pressure-inflated radius relation. Their dependence on the initial inflated radius, material properties and kinetics of chemorheological change is studied when the underlying elastomeric networks are neo-Hookean or Mooney-Rivlin. (2000): 74F05, 74F25, 74D10, 74E94. Mathematics Subject Classifications

show abstract

Section: Response During Scission and Re-crosslinkingsupporting

confidence: 85%

Section: Constitutive Equationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Thermally Induced Chemorheological Changes on the Inflation of Spherical Elastomeric Membranes

Wineman

Shaw

2005

J Elasticity

View full text Add to dashboard Cite

show abstract

“…Tobolsky proposed the Two-Network Hypothesis [8], examined theoretically by Flory [12], and computationally by Rottach and co-worker [28]. This approach has been applied with success to a variety of problems associated with the continuum thermomechanical behavior of temperature sensitive elastomers [31,35] and photomechanically coupled polymers [18]. The Two-Network approach is based on a multiplicative decomposition of the deformation gradient,…”

Section: Evolution Of the Stress-free Configurationmentioning

confidence: 99%

The mechanics of network polymers with thermally reversible linkages.

Long¹

2012

View full text Add to dashboard Cite

Encapsulated printed circuit boards typically use conventional thermosetting polymers which are difficult to remove without damaging the electronics if upgrades are needed. To improve the efficiency of maintaining printed circuit boards, network polymers with thermally reversible linkages were developed to provide an alternative class of encapsulation thermosets that could be easily and non-destructively removed and later reapplied. These polymers include functionalities that dynamically break and form covalent bonds. Over time, the connectivity of the network evolves, which causes the macroscopic stress in the material to relax and the permanent shape to change even if these processes are in equilibrium. With respect to removal, the equilibrium behavior of these processes changes if the thermodynamic state of the material is changed, which alters the number density of chains. If the number density of chains is reduced below the percolation threshold, the material exhibits a gel-point transition beyond which, it behaves as a viscous liquid. These two properties contrast sharply with conventional thermosetting polymers, which do not exhibit this relaxation mechanism nor a gel-point transition.To take advantage of such novel material capabilities at length scales relevant to electronics packaging, a continuum-scale constitutive model is needed that correctly accounts for the thermalchemical-viscoelastic behavior of such materials, especially since the state of the art for using 3 them is limited to experimental investigations. To meet this need, a continuum-scale, thermodynamically consistent free energy description of such materials is developed in this work. Paired with this free energy are non-equilibrium contributions associated with the topological rearrangement of the network as chains are added and removed as well as viscoelasticity. The model is calibrated and validated against experimental data published in the literature. Finally, simple encapsulation thermal-mechanical scenarios are examined that demonstrate a substantial difference in behavior between conventional polymer networks vs. those with thermally reversible linkages.4 Acknowledgment

show abstract

“…Recently, Wineman and collaborators have developed a theoretical framework for modelling the destruction and reformation of cross links in isotropic nonlinearly elastic materials (Wineman & Rajagopal 1990;Shaw et al 2005) and have explored its consequences for mechanical response (Huntley et al 2000;Wineman & Shaw 2007). The destruction of cross links is referred to as scission, which has the effect of degrading the original microstructure network in the material.…”

Section: Introductionmentioning

confidence: 99%

On dissolution and reassembly of filamentary reinforcing networks in hyperelastic materials

2008

View full text Add to dashboard Cite

We generalize a theory for modelling the scission and reforming of cross links in isotropic polymeric materials in order to treat anisotropic mechanical behaviour. Our focus is on materials in which elastic fibres are embedded in an elastic matrix. The fibres may have a different natural stress-free configuration than that of the matrix, e.g. the fibres may be initially crimped in the absence of load. The modelling process allows the fibres to dissolve as deformation proceeds and then to immediately reassemble in the current direction of maximum principal stretch. This results in softening, altered mechanical properties and the possibility of permanent set. We illustrate a rich variety of such mechanical behaviours in the context of uniaxial stretch. The phenomena illustrated have important implications for the influence of mechanical factors in the remodelling of fibrous soft matter including biological tissue.

show abstract

Chemorheological response of elastomers at elevated temperatures: Experiments and simulations

Cited by 91 publications

References 29 publications

Influence of Thermally Induced Chemorheological Changes on the Inflation of Spherical Elastomeric Membranes

Influence of Thermally Induced Chemorheological Changes on the Inflation of Spherical Elastomeric Membranes

The mechanics of network polymers with thermally reversible linkages.

On dissolution and reassembly of filamentary reinforcing networks in hyperelastic materials

Contact Info

Product

Resources

About