Elongation of HIPS is one of the necessary parameters to produce high-quality products. In a polymer force tolerance test, only the amount of force borne by the polymer is tested. But this is not enough! The behavior of the material monomers against pressure must also be investigated. The HIPS elongation test is a very interesting test that examines the extent to which the length of a polystyrene material increases under pressure. In this PETROPROVIDERS article, we want to examine the elongation of HIPS. This material is used in the manufacture of various devices; Therefore, it is necessary to perform various tests on it. Stay with us!
This is a test to determine the HIPS polystyrene resistance to stretching. This material has a high resistance but deforms due to high pressures. This deformation is an increase in length and change in the initial structure of polystyrene.
To calculate the percentage of elongation of HIPS, the amount of increase in material length is divided by the initial length. The resulting number is then multiplied by 100 to indicate the percentage increase in length.
The maximum rate of elongation is the extent to which the polymer finally reaches the pressure before breaking. A reversible elongation test is a test in which the material has an elongation but its structure does not change. In general, reversible testing is less stressful.
In the elongation test of HIPS, the timing of the test is very important; Because it must be determined with what pressure and at what time this material deforms and its length increases.
In general, hard plastics do not have much flexibility and do not deform. These materials break easily and will not have their original structure as the pressure increases.
Plastics that have high flexibility are better prepared for this test! These materials enlarge and deform with pressure resistance, But they do not break. Of course, it should be noted that if the pressure is much higher than the tolerance of this material, it will cause the material to break.
The tensile test is a test in which a material is pressed. In this test, a lot of pressure is applied to the material and the forces are recorded by precision sensors. These forces are eventually recorded on a graph and show very detailed information about the test and the HIPS resistance.
It should be noted that the graph drawn in this test is the stress-strain curve. This diagram shows the amount of pressure applied and the amount of increase in the length of high impact polystyrene.
In many tensile tests, the graph grows linearly at the beginning of the test. That is, the higher the pressure, the steeper the slope of the graph. In this test, the diagram follows the Hooke relation and is called the modulus of elasticity.
The modulus of elasticity is a very accurate measure of the hardness of a material seen at the beginning of a test. Furthermore, as the slope of the graph increases, the modulus of elasticity does not match; That is, the Hooke relation cannot be used. At this point, the deformation of the material becomes irreversible and the slope of the graph will be much greater.
The point at which the modulus of elasticity is not applicable is known as the point of the elastic limit or the fit limit. After this point, if the pressure increases, the sample deforms and no longer returns to its original state.
During the tensile test, the strain of the material can also be calculated. This is calculated using accurate measurements of material length changes.
The amount of strain in the diagram is known as two types: real strain and engineering strain. True strain is the ratio of the change in length to the original length that is calculated at any given moment. But engineering strain is the ratio of the change in length to the initial length that is calculated throughout the test.
To perform this test, you must comply with ASTM D638. In this standard, there are the necessary conditions to measure the change in length of the desired material such as high impact polystyrene (HIPS).
Using this standard, at least 5 samples must be tested. These specimens should be more than 150 mm long and 10 to 25 mm wide.
The elongation test of HIPS has 2 clamps. These clamps can be moved and the specimens fully fixed. In general, the distance between the clamps should be 100 mm. It should be noted that the specimens should be fixed inside the clamps and not shake during the test. The bottom clamp of the device is fixed and holds the specimen.
The top clamp on this device, in addition to holding the specimen, pulls it upwards. This increases the pressure on the material. This applies tensile force and increases the length of HIPS polystyrene.
After this step, sample information must be entered into the device to accurately record the amount of traction. It should be noted that the tensile speed in this test is usually 50 mm per minute. This speed may vary depending on different standard conditions.
In this test, the polystyrene material is stretched until it breaks. At the point of failure, the applied force and the time of the test are checked and plotted by the devices. At this point, the required curve is drawn and the elongation of HIPS is completed.
It should be noted that it is necessary to use the necessary formulas to measure the increase in length of polystyrene. Therefore, in addition to the numbers recorded by the device, formulaic calculations must also be performed.
In this article, we saw the elongation test of HIPS. HIPS polystyrene is used in various industries. This material is used for the production of plastics in various industries. It should be noted that the use of polymers in the plastic industry increases the impact resistance of plastics.
Elongation tests are required to determine the strength of the material against pressure and tension. This test is performed using standard methods and records accurate calculations of the material’s resistance to pressure.
In this test, the pressure curve applied to the polymer is recorded. In this curve, the test time, the pressure applied to the polymer, and the amount of pressure resistance of the material is recorded.
What do you think about the elongation of HIPS? Is this test sufficient to determine the exact tensile strength of polystyrene? Can this test be done at home with simulated conditions?