1 Scope
This part of ISO 34 specifies three test methods for the determination of the tear strength of vulcanized
or thermoplastic rubber, namely the following:
— method A, using a trouser test piece;
— method B, using an angle test piece, with or without a nick of specified depth;
— method C, using a crescent test piece with a nick.
The value of tear strength obtained depends on the shape of the test piece, speed
of stretching, and temperature of test. It can also be susceptible to grain effects
in rubber.
Method A: Using a trouser test piece
Method A, using the trouser test piece, is preferred because it is not sensitive to
the length of the cut, unlike the other two test pieces in which the nick has to be
very closely controlled. In addition, the results obtained are more easily related
to the fundamental tear properties of the material and are less sensitive to modulus
effects (provided that the leg extension is negligible) and the rate of propagation
of the tear is directly related to the rate of grip separation. With some rubbers,
the propagation of tear is not smooth (knotty tear), and analysis of results can be
difficult. [ 3 ]
Method B, procedure (a): Using an angle test piece without nick
This test is a c...
Open preview (PDF)Rubber, vulcanized or thermoplastic. Determination of tear strength - Trouser, angle and crescent test pieces