Effect of Cure Systems and Reinforcing Fillers on Dynamic Mechanical Properties of Chlorobutyl Elastomers for Potential Vibration-Control Applications

Abstract

Abstract The effects of four different types of cure systems upon the physical and viscoelastic properties of chlorobutyl elastomers have been investigated. Five different types of carbon black fillers have also been evaluated. Effects of carbon black loading were also studied. The basic conclusions that may be drawn from the experimental determination of the viscoelastic properties of these elastomers and the subsequent use of these to evaluate their potential in various vibration-control applications are as follows: (1) Both the red lead-thiourea cure system, and the resin-cure system give vulcanizates with very similar physical and dynamic mechanical properties. Use of a resin cure is preferable to a red lead-thiourea cure due to the much shorter cure time and lower cure temperature. (2) Chlorobutyl elastomers possess suitable viscoelastic properties for vibration-control applications, due to the diffuse nature of the glass-rubber transition in this class of polymer. Use of other types of fillers, such as silane-treated mica, may be useful in further broadening the temperature-frequency damping range of these materials by introducing additional damping mechanisms. (3) Increased loading of a moderately reinforcing carbon black improves the transmissibility and extensional damping characteristics of CIIRs. An intermediate loading of approximately 35 phr appears to work best for the constrained-layer configuration considered here. (4) An experimental determination of the temperature and frequency dependence of the viscoelastic properties of polymeric materials, coupled with the type of modeling described here, provides a convenient means of assessing the relative merits of various types of polymeric materials in the design of vibration-control systems.