Gas-induced damage in elastomeric composites

Gases may induce extensive and irreversible damage in elastomers when they are allowed to escape from the polymeric matrix. The damage is most evident as internal lacerations and also as an overall change in certain mechanical properties. The damage process, commonly termed explosive decompression failure, is really confined to gas-polymer systems which are initially equilibrated at high pneumatic stresses; greater than 10⁷ Pa. Two interrelated facets of this phenomenon are described in the context of elastomeric composites with particular emphasis on the role of interfacial quality. The results of an optical examination of the internal cracks found during a typical gas-induced rupture cycle are described. The system is a commercial silicone elastomer-glass filler composite where the fillers have been surface modified in order to alter the adhesive strength of the interface. The data indicate that the filler particles significantly modify the stress fields in the elastomer during gas-induced rupture. Essentially, the fillers suppress the development of the characteristic large scale axially symmetrical stress fields in the composites. This visual assessment of the damage is then related to the deterioration in certain mechanical properties of this current system.