The tensile modulus is the ratio of stress to strain (i.e. distance) generated by a sample under tension within the elastic range. It is one of the indicators that characterize the tensile properties of a material. The larger the tensile modulus, the greater the rigidity and the higher the strength. It is also called Young’s modulus and is represented by E.

The tensile modulus is calculated as follows:

E = Δf / Δh

Among them, Δf represents the change in stress between two points per unit cross-sectional area, and Δh represents the change in strain between two points.

The methods currently used to accurately measure the tensile elastic modulus include the extensometer method and the strain gauge method.

⑴ Extensometer method

An extensometer is an instrument used to measure the linear deformation between the two points where the measuring part contacts the sample. It usually consists of three parts: a sensor, an amplifier, and a recorder. It can be roughly divided into four categories: mechanical extensometer, optical extensometer, electromagnetic extensometer, and resistance extensometer.

Junhua PEEK currently uses a resistive extensometer, model Y50/25, with an accuracy of 0.5, where 50 is the gauge length and 25 is the maximum deformation. The installation method is to gently pinch the two force arms of the extensometer with a positioning pin inserted with two fingers, so that the specimen contacts the force arm, and fix the extensometer on the specimen with a rubber band through the hooks of the two force arms of the extensometer. After that, the positioning pin needs to be pulled out to move the force arm. Note that the knife edge line of the two force arms should be aligned and parallel to the axis of the specimen.

⑵ Strain gauge method

The strain gauge is a strain gauge that changes resistance as it deforms. It is glued to the surface of the sample in a specified direction, and the resistance of the strain gauge changes due to the strain on the surface of the sample. It is also called the resistance strain gauge method. It is roughly divided into three categories: static strain gauge, dynamic strain gauge, static and dynamic strain gauge, wired strain gauge, foil strain gauge, semiconductor strain gauge, etc. In addition, the strain gauge is equipped with corresponding sensors, which can measure physical quantities such as force, mass, pressure, displacement, torque, speed and their dynamic changes.

The calculation of PEEK tensile elastic modulus is based on the load stress borne by the specimen measured by the large sensor on the main beam of the testing machine, and the strain measured by the extensometer method and the strain gauge method, and is calculated using the modulus formula.

The following is the tensile stress-strain curve of PEEK, the main material sold by Junhua PEEK. The slope of the curve is the modulus of the material, measured using a Y50/25 resistance extensometer.

Note: 1—PEEK5600G 2—PEEK5600GF30 3—PEEK5600CF30 4—PEEK5600LF30

5—PEEKFE20 6—30%PEI+PEEK 7—Cross-linked PPSGF40 8—Linear PSSGF40

9—YS2722       10—CF/PEEK        11——GF/PEEK      12—GF/PPS）

Junhua PEEK is a company with a full industry chain that integrates PEEK (polyetheretherketone) resin polymerization, continuous extrusion molding of profiles such as plates, rods, and tubes, and the research and development, production, and sales of finished parts. PEEK (polyetheretherketone) is widely used in aerospace, automobile manufacturing, electronics, and medical fields due to its excellent comprehensive performance.

PEEK5600G pure material, although the tensile elastic modulus of the material is only 4GPa, its performance is much better than that of conventional materials such as PE, PVC, POM, PC, etc., and it can replace these conventional plastic materials in many fields.

The tensile elastic modulus of the enhanced and modified PEEK5600CF30 material can reach 20GPa, which can fully meet the performance requirements of products in multiple fields.

In the fields of aerospace and medical equipment, the tensile elastic modulus of the material is required to be higher. When the conventional PEEK5600CF30 cannot meet the requirements, Junhua PEEK has developed a continuous CF/PEEK thermoplastic composite material with a tensile elastic modulus of up to 60GPa, which can fully meet the stringent requirements of the fields of aerospace and medical equipment.