what is PBO?
Poly (p-phenylene-2,6-benzobisoxazole) (PBO) is a rigid-rod isotropic crystal polymer. PBO fibre is a high performance fibre developed by TOYOBO (Japan) and has superior tensile strength and modulus to Aramid fibres, such as Kevlar, Technora and Twaron. It also has outstanding high flame resistance and thermal stability among organic fibres. PBO fibre shows excellent performance, in such properties as creep, chemical resistance, cut/abrasion resistance, and high temperature abrasion resistance - far exceeding other Aramid fibres. PBO fibre's moisture regain is low (0.6%) and it is dimensionally stable against humidity. PBO fibre is quite flexible and has very soft hand, in spite of its extremely high mechanical properties.
Over the past ten years Future Fibres has pioneered the use of PBO for yacht rigging and has proven it to provide remarkable performance and longevity. PBO's properties deliver the lightest, smallest cables available on the market today.
what is Dyneema?
Dyneema is a high-performance polyethylene (HPPE) which is a subset of the thermoplastic polyethylene. It has extremely long molecular chains, which transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. It is highly resistant to corrosive chemicals, with exception of oxidizing acids. It has extremely low moisture absorption, has a very low coefficient of friction, is self-lubricating, and is highly resistant to abrasion (15 times more resistant to abrasion than carbon steel).
In relation to PBO, a Dyneema cable is around 10 percent heavier and 22 percent larger in diameter for the same level of stretch. It does suffer from creep which rules it out for side shrouds, however, its durability around corners makes it an ideal fibre for certain applications e.g. strops.
what is Kevlar?
Kevlar was introduced by DuPont in the 1970s. It was the first organic fibre with sufficient tensile strength and modulus to be used in advanced composites.
Kevlar is an aramid, a term invented as an abbreviation for aromatic polyamide. The chemical composition of Kevlar is poly para-phenyleneterephthalamide, and it is more properly known as a para-aramid. Aramids belong to the family of nylons. Common nylons, such as nylon 6,6, do not have very good structural properties, so the para-aramid distinction is important. The aramid ring gives Kevlar thermal stability, while the para structure gives it high strength and modulus.
Kevlar was the fore-runner to PBO and shares many of the same properties but cannot compete with PBO in terms of strength and stretch
what is Carbon?
Carbon fibre consists of extremely thin fibres about 0.0002-0.0004 inches in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in microscopic crystals that are more or less aligned parallel to the long axis of the fibre. The crystal alignment makes the fibre incredibly strong but requires a resin matrix to support the fibres. The resin matrix makes carbon fibre cables a relatively brittle solid, which brings with it certain problems, such as increased weight and the risk of impact.