Fibre Qualities
Comparative Characteristics
| Fibre | Tenacity of dry fibre (gm/denier) | Wet strength compared to dry strength | Rope shock load absorption | Specific Gravity | Able to float | Strength/ Weight ratio (av.) | Elongation & Creep |
|---|---|---|---|---|---|---|---|
| Sisal | 4-5 | Up to 120% | Poor | 1.5 | No | Fibre elongation: Dry 2.9%, Wet 3.4%. Rope elongation: Dry 13%, Wet 16%. Extension causes rupture. | |
| Manila | 5-6 | Up to 120% | Poor | 1.5 | No | Fibre elongation: Dry 2.8%, Wet 3.2%. Rope elongation: Dry 13%, Wet 15%. Extension causes rupture. | |
| Polyethylene | 6 | 100% | Good | 0.95 | Yes | 2.10 | High tenacity. Good recovery after stretch and extension at break of 50%. High creep. |
| Polypropylene | 6.5 | 100% | Very Good | 0.91 | Yes | 2.50 | High tenacity. Good recovery from stretch and elongation at break for ropes is 25-30%. High creep. |
| HT Polyester | 7-10 | 100% | Very Good | 1.38 | No | 2.25 | Elongation 35% at break. Low creep. |
| Nylon | 9 | 85-90% | Excellent | 1.14 | No | 3.00 | Elongation Dry 40%. Wet 35%. Moderate creep. |
| Aramid (Kevlar®) | 18-26 | 95% | Fair | 1.44 | No | Elongation 4% at break. Very low creep. | |
| Technora® | 28 | 100% | 1.39 | No | Elongation 4.5% at break. Low creep. | ||
| UHMwPE | 28 | 100% | 0.97 | Yes | Elongation 2-5% at break. |
Chemical Resistance & Degradation
| Fibre | Effects of acids | Effects of Alkalis | Effect of Organic Solvents | UV resistance in sunlight | Other | Resistance to aging* |
|---|---|---|---|---|---|---|
| Sisal | Degradation of acids in high concentration or temperature. | Resistant | Resistant | Good | Degradation by sea water, paints, detergents, chemical salts and fats | Good |
| Manila | Degradation of acids in high concentration or temperature. | Degradation by alkalis. | Resistant | Good | Degradation by paints, detergents, chemical salts and fats | Good |
| Polyethylene | Very resistant | Very resistant | Soluble in hot chlorinated hydrocarbons. | Good (UV stabilised) | Excellent | |
| Polypropylene | Very resistant | Very resistant | Soluble in chlorinated hydrocarbons. | Good (UV stabilised) | Excellent | |
| HT Polyester | Resistant to most mineral acids. Disintegrated by 95% sulphuric acid. | No effect cold. Slowly disintegrated by strong alkalies at the boil. | Generally unaffected. Soluble in some phenolic compounds. | Excellent | Excellent | |
| Nylon | Decomposed by strong mineral acids. Resistant to weak acids. | Little or none | Resistant, soluble in some phenolic compounds and in 90% formic acid. | Good | Excellent | |
| Aramid (Kevlar®) | Resistant to weak acids. Degradation by strong acids & bases in high concentrations or temperatures. | Resistant | Fair | Degrades in Chlorine bleach. | Excellent | |
| Technora® | Resistant to mineral and organic acids. Degrades in hydochloric, hydrobromic and sulphuric acids. | Resistant | Resistant | Resistant to sea water and steam. Sensitive to bleaching and sunlight. | Excellent | |
| UHMwPE | Chemically inert except for strong oxidising acids. | Resistant | Resistant to cold alcohols, ethers, esters, ketones & bleaches. | High | Excellent |
* for properly stored rope
Rope Abrasion Resistance & Heat Reaction
| Fibre | Surface abrasion | Internal abrasion | Heat reaction |
|---|---|---|---|
| Sisal | Fair | Good | Burns as fire touches flame. Supports combustion. |
| Manila | Good | Good | Critical temp is 150°C after which fibre burns at flame. Supports combustion. |
| Polyethylene | Fair | Good | Softens 100°C. Melts 110°C - 120°C. |
| Polypropylene | Good | Good | Shrinks rapidly from flame. Curls and melts at 165°C. |
| HT Polyester | Excellent | Excellent | Softens 228°C. Melts 255°C. |
| Nylon | Very Good | Excellent | Softens 229°C. Melts 249°C - 260°C. |
| Aramid (Kevlar®) | Fair | Good | 371°C decomposition |
| Technora® | Very Good | Very Good | 500°C+ decomposition |
| UHMwPE | Excellent | Excellent | Melts 152°C. |
