Polyethylene Fiber Molecular Mobility Control
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Solution Overview
Problem
Polyethylene fibers used in marine applications face challenges with creep resistance, strength retention, and wear resistance, particularly in saltwater environments, where increased creep and breakage occur due to reduced strength in bundles.
Innovation Solution
A polyethylene fiber with a specific composition fraction and relaxation time of its high mobility component, as determined by pulsed nuclear magnetic resonance (NMR) analysis, and controlled molecular structure to enhance creep resistance and strength retention, while maintaining wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a comonomer is introduced into the molecular chain of polyethylene to improve creep resistance, then creep resistance is improved, but strength decreases and crystallinity decreases leading to reduced wear resistance and weather resistance
Solution Approach 1:
The invention changes the molecular mobility parameters by controlling the composition fraction and relaxation time of specific molecular components. By adjusting these parameters without introducing comonomers, the patent achieves improved creep resistance while maintaining strength and crystallinity. The high mobility component is controlled to have a composition fraction of 5-20% and relaxation time of 100-1000 μs, which resolves the contradiction between creep resistance and strength.
2Reliability
If a weather-resistant agent is formulated to improve weather resistance, then weather resistance is improved, but further improvement is desired particularly from the viewpoint of strength retention in salt water environment
Solution Approach 1:
The invention changes the molecular structure parameters by controlling the composition fraction and relaxation time of the high mobility component. This molecular-level parameter control provides superior strength retention in salt water environments compared to conventional weather-resistant agents. The specific parameter ranges (composition fraction: 5-20%, relaxation time: 100-1000 μs) enable the fiber to maintain both weather resistance and high strength retention rate without relying on external additives.
3Adaptability or versatility
If polyethylene fibers are used as a bundle in salt water environment, then application requirements are met, but when one yarn breaks the load on other yarns increases causing accelerated breakage and creep
Solution Approach 1:
The invention changes the molecular mobility parameters to achieve superior strength retention in bundle configurations. By controlling the high mobility component parameters (composition fraction: 5-20%, relaxation time: 100-1000 μs), the fiber maintains high strength retention rate even when used in bundles in salt water environments. This prevents the cascading failure mode where one broken yarn transfers excessive load to remaining yarns, thereby improving the reliability of bundle usage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fiber exhibits excellent creep resistance, high strength retention, and improved wear resistance in marine environments, effectively addressing the issues of bundle failure and environmental stress.
Implementation Method 1
when a free induction decay (M(t)) of the polyethylene fiber at 90° C. measured by a pulsed nuclear magnetic resonance (NMR) solid echo method is approximated to three components
Data Source
AI summary
A polyethylene fiber wherein when a free induction decay (M(t)) of the polyethylene fiber at 90° C. measured by a pulsed nuclear magnetic resonance (NMR) solid echo method is approximated to three components of a component (α) having a lowest mobility, a component (β) having an intermediate mobility, and a component (γ) having a highest mobility, by fitting using formula 1 (M(t)=α exp(−(½)(t/Tα)2)sin bt/bt+β exp(−(1/Wa)(t/Tβ)Wa)+γ exp(−t/Tγ)), a composition fraction of the component (γ) having the highest mobility is 1% or more and 10% or less, and a relaxation time of the component (γ) having the highest mobility is 100 μs or more and 1000 μs or less.