Influence of Thermally Induced Chemorheological Changes on the Inflation of Spherical Elastomeric Membranes
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.
Key wordselastomers membranes scission and crosslinking chemorheology thermal effects.
Mathematics Subject Classification (2000)74F05 74F25 74D10 74E94
Unable to display preview. Download preview PDF.
- 6.A. Jones, An experimental study of the thermo-mechanical response of elastomers undergoing scission and crosslinking at high temperatures. PhD dissertation, University of Michigan (2003).Google Scholar
- 9.J.A. Shaw, A. Jones and A.S. Wineman, Chemorheological response in elastomers at elevated temperatures: experiments and simulations. J. Mech. Phys. Solids, in press.Google Scholar
- 11.A.V. Tobolsky, Properties and Structures of Polymers, Chapter V, pp. 223–265, Wiley, New York (1960).Google Scholar