Principle:

The test specimen is extended along its major longitudinal axis at a constant speed until the specimen fractures or until the stress (load) or the strain (elongation) reaches some predetermined value. During this procedure, the load sustained by the specimen and the elongation are measured.

Principle:

The pendulum is raised to a measured point, and it is then released. The weighted end of the pendulum gains speed as it swings toward a mounted molded bar of the test plastic. It strikes the bar, breaks it, and the pendulum loses energy while breaking the plastic bar. Therefore it does not swing as high. The energy lost by the pendulum is equated with the energy absorbed by the test specimen during the breaking process.

Principle:

Immersion of test specimens in fluids under controlled stress or strain.

The simultaneous action of the chemical and of the stress on the specimen can lead to stress cracking phenomena, hardly predictable by the simple immersion without stress.

Principle:

The tests most commonly used by the plastics industry to measure short-term thermal capability are ASTM D648, Standard Test Method for Deflection Temperature of Plastics Under Flexural Load and ISO 75, Plastics –Determination of Temperature of Deflection Under Load. These tests are commonly referred to as Heat Distortion Temperature (HDT) or Deflection Temperature under Load (DTUL).

Both tests are similar in that the test specimen is supported at two points while a load is applied to the center. The temperature is increased at a constant rate until the specimen deflects a specified amount as indicated by a dial micrometer.

HDT can only be used as a general indicator of short-term thermal capability. It is useful for comparing similar materials but can be misleading if, for example, an amorphous material is compared to a semi-crystalline material. It doesn’t provide any information about long term thermal stability.

The actual loads and performance requirements will dictate the suitability of the material. Many semi-crystalline resins can be used in applications that experience temperatures higher than their deflection temperature value.

Principle:

The drop weight impact tester mainly applies instantaneous impact force to test samples such as plastics, organic glass, building materials, ceramics, and paints to test the damage degree and impact energy of the materials.

Principle:

The rockwell hardness tester measures the hardness of materials by determining the depth of penetration of an indenter under a large load compared to the penetration made by a preload. The process involves the following steps:

1. A preliminary test force (preload) is applied to the material using a diamond or ball indenter to create a small indentation. This helps to break through any surface finish and establish a zero reference position.

2. An additional load (major load) is then applied to the indenter, causing it to penetrate further into the material.

3. After holding the major load for a specified dwell time, the major load is removed, leaving only the preliminary test force.

4. The depth of the indentation left by the major load is measured. The Rockwell hardness number (HR) is calculated based on the difference in depth between the preload and the major load.