Measuring thermal expansion or swelling of rubbers - using elongated I=section test-piece hanging in small chamber

摘要

The coefficient of expansion of a rubber is measured using an 'I' profile test piece suspended from a bracket so that a fork on an adjacent rod can rest on the lower end of the test piece. The test piece holder is immersed in a vessel for contg. a fluid medium. Longitudinal extension or contraction of the test piece can be monitored above the vessel by measuring changes in position of the upper end of the rod which is carried by the lower end of he test piece. Used for measuring either thermal expansion or solvent swelling effects by enclosing the vessel in e.g. a thermostatically controlled bath and filling the vessel with e.g air or an oil or other liq. swelling medium. Compared with established test methods, the test specimen is simpler to prepare than an 'O'-ring specimen. The elongated test piece form gives a more direct and sensitive indication of longitudinal expansion/contraction than the volumetric change of a small cube of material.