PBO fiber has four super special properties, namely strength, modulus, heat resistance and combustion resistance.
PBO, as the super-performance fiber of the 21st century, has excellent physical, mechanical and chemical properties. Similar to meta-aramid, it also equips heat-resistant and flame-retardant property. And it has twice the strength and modulus of Kevlar fiber. However, the physical and chemical properties are well above Kevlar, which has been in the leading position in the field of high-performance fiber to date. A PBO filament with a diameter of 1 mm can be lifted to a weight of 450 kg, and the strength thereof is more than 10 times that of the steel wire fiber.
Kevlar (r) is a registered trademark of high-performance fiber invented and produced by DuPont, and it is also a famous brand that DuPont is proud of. More than 30 years ago, Kevlar (r) was born in DuPont's laboratory as a kind of para-aromatic polyamide, which shows many excellent properties and a wide range of applications. The unprecedented and distinctive Kevlar (r) fiber, successfully invented by DuPont scientists, is more than five times stronger than steel at the same weight, changing the direction of industry experts and leaders looking to the future. The product has a soft feel, good fluffiness, drape, moisture absorption and permeability and high strength, wear resistance, good drape finish, colorfastness, as well as fire carbonation and other excellent characteristics, so as to meet the quality requirements of high and medium grade flame retardant clothing and decorative fabrics.
PBO, the abbreviation for Polyphenylene Benzobisoxazole, is a composite reinforced material that first developed in the United States in the 1980s. Thanks to the high performance, PBO applications include rope & cable, aluminum extrusion, personal protection, automotive industry, and even outer space. As one of the most promising human-made organic fiber, it has been called the superfiber of the 21st century.
Kevlar is the brand name of an aramid fiber material product developed by DuPont in 1965. This high-intensity material was first used commercially in the early 1970s. In general, Kevlar can be used alone or as part of composite material (combine with another material) to increase strength. It can be found in the field of vehicle, aircraft, ship, mining, consumer products, etc.
PBO and Kevlar both have excellent physical, mechanical, and chemical properties. However, there are still some differences between them.
The modulus shows the ease of elastic deformation of the material—the higher the modulus, the less the elastic deformation. According to the latest research findings, PBO has more than twice the modulus of Kevlar (PBO - 280 GPa, Kevlar - 131 GPa). This directly affects the tensile strength. Kevlar is 5 times stronger than steel of the same mass. And a PBO wire with a diameter of 1mm can lift up to 450kg, which is more than 10 times stronger than steel fiber.
PBO can protect against thermal hazards up to 600℃, while Kevlar is 480℃. Heat resistance mainly depends on the melting and decomposition temperature at which the fiber begins to break down. A fiber with higher decomposition temperature can create fabrics with better heat resistance, effectively resist melting, shrinking, and charring.
Flame retardancy is closely related to limiting oxygen index (LOI). It is generally considered that LOI less than 22 is a flammable material. LOI between 22-27 is a combustible material. LOI greater than 27 is flame-retardant material. As for LOI of PBO and Kevlar, 69 for the former, 29 for the latter. Thus, none of them will drip ignite or support combustion.
PBO and Kevlar are highly desirable textile raw materials for being soft, lightweight, and high tensile strength. However, Kevlar is a more popular choice for protective equipment such as bulletproof vests, heat and cut resistant gloves, firefighter uniforms. The reason is that the tenacity of PBO is easily affected by UV light, making it less durable. Kevlar provides better protection and performance in a variety of industries, keeping wearers safe and comfortable.
PBO and Kevlar have superior natures that allow them to be used in very demanding applications, even in various civil engineering. However, Kevlar has a relatively low compressive strength compared to PBO. So it can serve as a reinforcing material for construction, but not as a primary structural material.
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Nomex is the trademark for a flame-resistant meta-aramid developed by DuPont. Nomex, like Kevlar, is an aramid but Nomex is a "meta" aramid, and Kevlar is a "para" aramid. The variant "meta" just has a different location for the different compounds than the variant "para". This makes Nomex have good thermal, chemical and radiation resistance for a polymer material. For example, the firefighters' suits are made of Nomex because it is resistant to fire and chemical. But this also makes Nomex have a poorer strength and a lower resistance to heat than Kevlar. Nomex is made in the USA and also Spain by Dupont. For the aluminum extrusion process, it can withstand 450˚F / 230˚C.
Polyester is a synthetic polymer, which made of purified terephthalic acid (PTA) or dimethyl ester dimethyl terephthalate (DMT) and mono ethylene glycol. It doesn’t have high resistant to heat, that is why it usually used at the very end of the process where the profile is cooler. For the aluminum extrusion process, it can withstand 300˚F / 150˚C.