How to choose between ordinary polyacrylonitrile fibers and flame-retardant polyacrylonitrile fibers? A deep interpretation of the LOI value! 

Polyacrylonitrile fibers (acrylic fibers) are widely used in outdoor rope nets, safety nets, concrete reinforcement, and other fields due to their properties such as resistance to sunlight, weathering, and softness and warmth. However, in some special scenarios (such as firefighting, mining, public transportation), the flame retardancy of ordinary polyacrylonitrile fibers may not meet safety requirements. At this time, flame-retardant polyacrylonitrile fibers need to be selected. The key indicator for measuring flame retardancy is the LOI value (limiting oxygen index). Below, from the perspective of the LOI value, we will help you clarify the selection ideas for the two types of fibers. 

1. What is the LOI value? Why does it determine the flame retardancy level of the fibers? 

The LOI value (limiting oxygen index) refers to the minimum oxygen concentration (expressed as a percentage by volume) required for a material to sustain combustion in a nitrogen-oxygen mixture. In simple terms: The higher the LOI value, the more difficult it is for the material to burn, and the better its flame retardancy. 

Common polyacrylonitrile fibers: The LOI value is usually around 18-20%, making them flammable fibers. When exposed to a fire source in the air (with an oxygen concentration of approximately 21%), they will continue to burn. Even after removing from the fire source, they may still continue to burn. 

Flame-retardant polyacrylonitrile fibers: After being modified through copolymerization or by adding flame-retardants, the LOI value can be increased to 28-32% or even higher. They are not easily ignited in the air and can extinguish themselves quickly once removed from the fire source. 

If your product's usage environment has specific requirements for flame retardancy, it is necessary to choose flame-retardant polyacrylonitrile fibers. During the procurement process, you can request the supplier to provide a LOI value test report, which is a relatively intuitive indicator for measuring the flame retardant performance. 

II. Application Comparison: Which fields must use flame-retardant types? 

Depending on the usage environment and safety standards, the requirements for the LOI value vary in different scenarios. 

Common outdoor scenarios (rope nets, sunshade nets, geotextiles): The general environment does not involve open flames. Ordinary polyacrylonitrile fibers (with an LOI value of 18-20%) can meet the usage requirements. Their light resistance and weather resistance are sufficient to withstand sun exposure and rain. 

Fire protection, mining, and public transportation interiors: These scenarios have specific requirements for flame retardancy. Usually, flame-retardant polyacrylonitrile fibers with an LOI value of over 28% are needed. When used as the outer layer of firefighting suits, they must also possess high-temperature resistance and resistance to molten substances; when used in public transportation seat fabrics, attention should be paid to the smoke density and the release of toxic gases during combustion. 

Industrial filtration materials: If the filtration environment involves high temperatures or potential fire sources (such as dust removal systems), it is recommended to use flame-retardant polyacrylonitrile fibers to reduce the risk of fire. 

Summary and Selection Suggestions 

When purchasing polyacrylonitrile fibers, the following principles are recommended for selection: 

Consider the application environment: For ordinary outdoor scenarios, the regular type can be selected; for scenarios involving open flames or fire safety, the flame-retardant type must be chosen. 

Regarding the LOI value requirements: The supplier is required to provide a LOI value test report. For flame-retardant types, it is usually required to be ≥ 28%. 

Balanced assessment of functions: When used for fire protection or protective products, in addition to flame retardancy, attention should also be paid to the heat resistance, melt resistance and strength retention rate of the fibers. 

Shandong Huimin Taili Chemical Fiber Products Co., Ltd.: http://www.sdzwhq.cn/, located in "China's Rope Net Capital", mainly produces polypropylene high-strength yarn, polypropylene colored yarn, polypropylene fibers, polyester fibers, polypropylene acrylic fibers, polypropylene net-like fibers, safety ropes, safety nets, etc. We can provide either ordinary or flame-retardant polypropylene acrylic fibers according to the application requirements. Welcome to request samples for testing. 

Contact Information:

Contact Person: Wang Yuanwen 

Mobile phone: 1369543938 

Telephone: 0543-5690985 

Fax: 0543-5690985 

Address: Rimonnet Industrial Park, Qinghe Town, Binzhou City, Shandong Province