Today’s synthetic fibres allow ropes to be custom made to suit the individual purpose.
Nautilus Braids carries the following fibres:
Nylon has up to 8gms/denier tenacity with a specific gravity of 1.14 (which means it sinks) in fresh and salt water. Good UV resistance. Does not absorb water. Melts at 260°C. Has up to 40% stretch at break.
Again, this has 8-9gms/denier tenacity but with a specific gravity of 1.38 (which means it sinks). Good UV resistance. Does not absorb water. Resistant to acids and alkali. Melts at 255°C. Will stretch to 30% at break but generally has less stretch than nylon. White Polyester is stronger than coloured Polyester.
Polyethylene is usually extruded as a monofilament and is available in 500 or 1000 denier. It has a specific gravity of 0.91-0.94 (depending on blend) so it floats. Melts at 120°C. Relative low strength at 1.84 -3.4gms/denier. UV resistance is good. Mainly used for ski ropes and the like. Will stretch to 65% at break.
Polypropylene is normally used in lower quality ropes but can be extruded in a slit film or a fibre. The specific gravity is 0.855 so it is quite buoyant and floats. It has a low melting point at 160°C. Tenacity is 3.5-4.0gms/denier but it can have a higher tenacity 5.0gms/denier.
Ultra High Molecular Weight Polyethylene (UHMWPE)
UHMWPE is one of the strongest fibres known to man. UHMWPE is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene, (HMPE), it has extremely long chains resulting in a very tough material, with high impact strength.
There are many manufacturers that claim various similar strengths of fibre, some of which do not live up to their claims, others do. UHMWPE has a tenacity of 35-39gms/denier and a very low stretch 2-5% at break. Although it has very low stretch, it will creep if left under tension. UHMWPE tends to get stronger as it creeps, until it will start to loose strength with use. It has a specific gravity of 0.97 which means it floats. Very good light fastness. Melts at 147°C.
Vectran is a thermo tropic crystalline fibre. Strength of 25ms/denier with no or very little stretch. It is sensitive to sunlight with poor UV stability. It has a very high melting point 400°C and is often used in sheets that are required to slip on drums where heat generation is high. It has a high specific gravity of 1.37gms/denier, so it will sink in most solutions. Read More Aramid – High modulus Aramid fibre has a specific gravity of 1.45 and a tenacity of 19gms/denier. It is used in ropes for its high melting temperature of 550°C. Elongation at break is 2.4%.
PBO (Zylon) Polyphenylene Benzobisoxazole
PBO is rarely used as a rope but has the highest tenacity at >37gms/denier. Like Vectran, it has a crystalline structure. It has a specific gravity of 1.54 and thus sinks. Melts at 650°C. Stretch at break is 2.5%. It is very expensive and only used for specific applications.