What Is PBO Fiber?
PBO fiber (Zylon) is a fiber made from a material called polyparaphenylene benzobisoxazole.
It refers to a fiber with high strength, modulus of elasticity, heat resistance, and flame resistance. While ordinary fibers decompose in high-temperature environments, PBO fibers are resistant to decomposition even in extremely high-temperature environments (650°C).
In addition, PBO fiber maintains high durability at 500°C. The durability, heat resistance, and modulus of elasticity of PBO fiber are quite strong, and are the highest among organic fiber products currently on the market.
Uses of PBO Fibers
The more polymeric a fiber is, the more molecules are bound together to make a hard and strong product; PBO fiber, being a polymeric fiber, has high heat resistance and durability. Taking advantage of this feature, PBO fibers are mainly used in situations where they are exposed to high temperature environments.
Aramid fiber, which was created in the 1960s, is another fiber with superior performance, but demand for PBO fiber has been increasing in recent years due to its superiority over the two.
Specific uses of PBO fiber are as follows:
1. Machine Protectant
In terms of machinery, for example, metals become quite hot when welding. Since most robots are made of metal or resin, it is not uncommon for them to melt from the heat during welding if they are left as they are.
Therefore, by covering the robot with a fabric made of PBO fiber as a protective agent, the robot becomes highly durable.
2. Firefighting Uniform
Firefighting uniforms made with the flame-retardant properties of PBO fiber are useful for rescuers who jump into a fire scene without fear of burns.
3. Safety Gloves
Because of its high strength, elasticity, and heat resistance, it is also used as a raw material for safety gloves. Compared to leather products, synthetic fibers, and cotton, it has an overwhelming cut-preventive effect, is lightweight, and does not easily deteriorate over time.
4. Reinforcement
Because of its high strength and modulus of elasticity, it is often used to reinforce rubber and resin products. If it does not meet the application as a stand-alone fiber, it can be composited with other fibers to make a product.
Characteristics of PBO Fiber
PBO fiber is made from polyparaphenylene benzobisoxazole, or PBO for short.
PBO fiber has considerably higher durability and heat resistance than polyester, which is usually used for coating, because of its molecular arrangement, which is very different from that of other materials. In synthetic fibers, molecules exist in a dispersed state regardless of the fiber axis.
In contrast, the structure of PBO fiber shows that the molecules are arranged almost parallel to the fiber axis. Normally, the more parallel the molecules in a fiber are to the fiber axis, the more durable it is. This is what gives PBO fiber its incomparably high durability.
Structure of PBO Fiber
PBO fiber is made by a process known as “liquid crystal spinning.” PBO molecules, which are polymers, are usually liquid, but their molecular arrangement is regular and their physical properties are like crystals, which is why they are called the liquid crystalline state. This phenomenon is similar to the state of matter during the transition from solid to liquid or liquid to gas, and in the case of PBO molecules, they are stable in the liquid crystal state.
Using this stable state, PBO fiber is made into a fiber by spinning the molecular chains while blending them well. Fibers produced by this liquid crystal spinning are often highly durable, and in addition to PBO fibers, aramid fibers are also produced by the same method.