The following chart illustrates many of the characteristics of synthetic fibers that are commonly used in twines. The requirements needed for a specific application will determine which fiber is best. Example: If the requirement is for a lightweight twine that floats and is resistant to mildew, then polypropylene or polyethylene will be best. If, on the other hand, a twine with high tensile strength is to be used underwater, then nylon or polyester will be best.
Ultra High | ||||||||
Molecular Weight | ||||||||
Nylon | Polyester | Polypropylene | Polyethylene | Polyethylne | ||||
(Polyamide) | (UHMWPE) | |||||||
Strength | ||||||||
Grams per denier | 7.0- 9.5 | 6.5 -8.5 | 6.0-7.3 | 6 | 30 | |||
Shock Load Absorption | Excellent | Good | Fair | Fair | Fair | |||
Elongation | ||||||||
Percent on Break | 18-25% | 22% | 24% | 15-20% | 3.50% | |||
Creep | Moderate | Moderate | High | High | Moderate | |||
Weight | ||||||||
Specific Gravity | 1.14 | 1.38 | 0.89 | 0.95 | 0.97 | |||
Floats | No | No | Yes | Yes | Yes | |||
Effects of Moisture | ||||||||
Water Absorption | 2-8% | 1% | None | None | None | |||
Dielectric Properties | Poor | Poor | Excellent | Excellent | Excellent | |||
Degradation | ||||||||
Resistance to Ultra Violet | Good | Good | Fair | Fair | Fair | |||
Resistance to Rot & Mildew | Excellent | Excellent | Excellent | Excellent | Excellent | |||
Thermal Properties | ||||||||
Melts at | 420-480 F | 482 F | 330 F | 275 F | 297 F | |||
Resistance | ||||||||
Resistance to Acids | Fair | Fair | Excellent | Excellent | Excellent | |||
Resistance to Alkalis | Very Good | Very Good | Excellent | Excellent | Excellent | |||
Resistance to Oil and Gas | Very Good | Very Good | Very Good | Very Good | Very Good |