Objective:

1. To investigate the tensile behavior of polymers.
2. To determine the following properties:
   1. The relationship between tensile stress and strain.
   2. Modulus of elasticity.
   3. The tensile strength.
   4. Percentage of elongation.

Introduction:

   Strength can be defined as the ability of a material to resist applied forces without yielding or fracturing. 

   The strength of materials can be determined using some kind of tests called Tensile Test, in which a tensile load (force) is applied to a specimen of the material and its extension is measured with respect to this load, i.e. Tensile test is used to measure the force required to break a specimen and the extent to which the specimen stretches or elongates to that breaking point.

   Applying this test, the Stress-Strain Diagram is produced, and we can investigate the tensile behavior of the material and its properties from this diagram.

Stress (σ): the force acting per unit area. 

Strain (ε): the measure of the elongation or contraction of a line segment in the body.  

   In this experiment we are studying the tensile behavior of some polymers (Plastics) under specific conditions (such as temperature, initial geometry and speed of testing .etc.)

   The testing speed: is the rate of separation of the grips of the testing machine during the test (expressed in [mm/min]). 

   The tensile behavior of polymers depends on many factors rather than the composition and structure; it depends also on the temperature T and the strain rate (testing speed).

   Increasing the temperature results in decreasing of modulus of elasticity (E) and Tensile strength TS but increasing in Ductility (%EL).

   The effect of strain rate is completely the opposite of T; while the strain rate of testing increases the ductility of the material decreases and it seems stronger.

* Continue reading the full report from the attached PDF below, pages 47-51

Tensile Testing of Plastics.pdf