Aramid fiber testing

1. Test items
Mechanical properties test:
Tensile strength: This is one of the most important indicators for measuring aramid fiber, which is related to its application reliability in key fields such as bulletproof and aerospace. During the test, the maximum bearing capacity of the fiber in the process of axial tension until fracture must be accurately measured to ensure that it can meet the high strength standards required for making bulletproof vests to resist bullet impact and aircraft to withstand flight stress.

Elastic modulus: reflects the rigidity of the fiber and determines its deformation characteristics when subjected to force. High modulus aramid fiber can ensure the stability of shape in aviation structural parts, and professional instruments are required to measure the ratio of stress to strain of the fiber in the elastic deformation stage.

Heat resistance test:
Thermal decomposition temperature: Determine the critical temperature at which aramid fiber begins to chemically decompose. Only when the thermal decomposition temperature is high enough can it meet its application in high-temperature industrial environments or engine components, ensuring that the performance does not deteriorate under long-term high temperatures.

High temperature strength retention rate: Simulates actual high temperature conditions, tests the ratio of the remaining strength to the initial strength of the fiber after a certain period of time at a specific high temperature, and intuitively reflects its heat resistance stability.

Chemical stability test:
Acid and alkali corrosion resistance: Soak the aramid fiber in acid and alkali solutions of different concentrations and types for a certain period of time, observe the changes in the fiber surface morphology, mechanical properties, etc., and determine whether it can withstand the corrosive environment faced by chemical pipelines and marine facilities.

2. Test method
Mechanical property test: Use a universal material testing machine to prepare fiber samples in accordance with standard specifications, apply tensile force at a constant rate, and the instrument automatically records force and displacement data, draws a stress-strain curve, and calculates the tensile strength and elastic modulus based on this.

Heat resistance determination: The thermal decomposition temperature is measured by a thermogravimetric analyzer, and the fiber mass changes with temperature under programmed temperature rise. The corresponding temperature when the mass decreases sharply is the thermal decomposition temperature; the high-temperature strength retention rate is measured by first placing the fiber in a high-temperature furnace, and then using a universal material testing machine to measure the remaining strength.

Chemical stability assessment: Acid and alkali corrosion resistance test: After the fiber is immersed in an acid and alkali solution, the surface microscopic changes are observed with a microscope, and the mechanical properties are re-measured with a universal material testing machine.

3. Testing standards
In China, GB/T 20732 "Liquid unsaturated polyester resin for fiber reinforced plastics" and other relevant standards involve some performance requirements of aramid fibers; internationally, ASTM standards provide detailed specifications for the mechanical, thermal, and chemical performance testing of aramid fibers to ensure that product quality is in line with international standards and facilitate trade circulation.

4. Significance of testing
From the perspective of consumers, testing ensures that aramid fiber products with qualified quality and performance that meet standards are purchased, such as reliable bulletproof equipment and high-performance sports equipment, to ensure safety and effectiveness of use. For manufacturers, based on testing, production processes are optimized, high-quality raw materials are selected, and product competitiveness is improved. At the market supervision level, strict testing can regulate industry development, eliminate inferior products, and promote the steady development of the aramid fiber industry.