ABSTRACT
VECTRAN™ is Kuraray’s high-performance multifilament yarn spun from liquid crystal polymer. Vectran fiber is a versatile fiber that is in only filament form not in a staple because it is difficult to cut. This
fiber is widely used in the military as well as aerospace industries as a high-performance fiber. It is developed for the overcome physical, chemical as well
as thermal properties of Kevlar and Dyneema fiber. Vectran is a liquid crystal
polymer and exhibits excellent tensile properties. It is fully aromatic polyester fiber. The molecules arranged in the structure of
Vectran fiber is highly oriented. Vectran is five times stronger than steel
and ten times stronger than aluminum.
Keywords: Flex, Creep, Uniqueness, Oriented
INTRODUCTION Vectran fiber is developed by Kuraray Co. Ltd. For the NASA in the mars mission. Pathfinder is the first robot that is landed on Mars. Normally for the landing purpose balloon is used which is made of fully aromatic polyester i.e Vectran. Vectran is a polyester (polyacrylate) fiber made from polymer with a high degree of crystallinity. It is spun and uniformly treated at high temperatures.
Vectran is a second-generation super fiber that followed Kevlar and Dyneema which are referred to as the first generation of super fibers. Vectran is being considered as a possible replacement material primarily due to improved time dependant behavior. The manufacturer claims the material exhibits no measurable creep when loaded up to 50% of its breaking load. This statement is contradicted by NASA testing but the measured and quantified creep is on the order of five times less than Kevlar.
MANUFACTURING PROCESS
- Vectran has a broad range of characteristics including high strength and high modulus(tensile properties), low moisture absorbency, high dimensional stability (creep properties), excellent thermal properties, fiber to fiber abrasion resistance, cut resistance, chemical resistance, and ultraviolet light resistance.
- The manufacturing of Vectran fiber is done by melt spinning and is described below shortly.
- P-hydroxybenzoic acid + 6 hydroxy-2 naphthalic = Poly para arylate (Raw material for the manufacturing of Vectran)
- The Vectran fiber is also a Liquid Crystal Polymer (LCP). There is two monomers are used to prepare raw material for the Vectran fiber i.e p-hydroxybenzoic acid and 6 hydroxy-2 naphthalic. These two monomers give one polymer i.e poly para arylate.
- These two monomers are feed to the melt spinning in the hopper. Normally what happens when any other monomers are feed in the hopper and they combine together that time they are not oriented. The molecules of those monomers are randomly arranged and for the orientation of molecules the winding is done but in the case of Liquid crystal polymer (VECTRAN), the monomers which are fed into the melt spinning when they combine that time the molecules of that monomers are highly oriented and when they come into contact with a winding zone there also the orientation of molecules will take place. Orientation is required to improve strength and other physical properties. The orientation of Vectran fiber is about 95%.
Comparison of Vectran to the other material:
|
Material |
Density gm/cc |
Tensile strength
gpa |
Tensile modulus |
|
Vectran |
1.4 |
3.0 |
103 |
|
Stainless steel |
7.9 |
2.0 |
210 |
|
Aluminum |
2.8 |
0.6 |
70 |
CHARACTERISTICS:
High-strength and
high-elasticity
It is a very strong
to be called a super fiber and difficult to rip.
Low moisture
absorption
Moisture absorption
of this fiber is as a lower side because of this no loss in a tenacity or change
in dimensions when the fiber is in wet condition.
Dimensional stability
Ideal as a wire
replacement because its dimensions undergo almost no change. In addition,
thermal contraction is very low when heated.
Abrasion resistance
As compare to kevlar
fiber it gives higher abrasion resistance property.
Cut/shearing resistance
Index of cut
resistance of this Vectran fiber is more and it is difficult to cut.
Resistance to
chemical
High resistance to
many chemicals, especially acids
Vibration damping
Quickly absorbs the
vibrations.
Shock absorption
Absorbs the energy of
shocks and its composites show high resistance to compressive and bending
stress.
Electrical insulation
Excellent electrical
insulation properties because it is non-absorbent.
Physical properties:
- Tensile strength:3.0 GPA
- Specific modulus:7400
Creep resistance:
- Creep resistance is a term used in materials science that refers to a solid material's ability to resist creep, which refers to the tendency of a material to slowly deform over a long period of exposure to high levels of stress.
- Kevlar is also known for low creep but Vectran is more superior in terms of creep resistance. The problem with Kevlar is that at a high temperature the creep will develop. At normal temperature it works in terms of creep(low creep) Vectran can sustain at high temperature.
Cut resistance: (for getting resistance to cut)
- Cut resistance is always expressed in an index and it is 0 to 5. And Vectran fiber having cut resistance is 3.4.
- Cut resistance depends upon the force required to cut. When cut resistance is high then the force required to cut the material is on the higher side.
Flex resistance: (Resistance to folding and unfolding)
Flex resistance of liquid crystal polymer(Vectran) is better than aramid.
Abrasion
resistance:
Average cycles to
fail
Dry condition wet condition
16672 21924
Abrasion resistance of Vectran fiber is on the higher side. Interesting thing is in the wet condition, it sustains better as compare to dry condition.
Thermal properties;
- Melting point(Temp):350
- Hot air shrinkage: 0.1%
- Boiling water shrinkage: 0.1%
- As the temperature goes below 0 (sub-zero) then the Vectran fiber increases its strength.
- Burning behavior is the same as a Kevlar.
Chemical properties:
Resistances to a chemical from this we can say that Vectran has very good resistance to inorganic solvents and alkalis, and excellent resistance to organic solvents. It is hydrolytically stable.
Applications:
Ropes and cable
High strength with no creep allows the manufacture of high-performance ropes
that stable to extended loads. Vectran is an outstanding candidate for the replacement of steel constructions.
Aerospace and military
The first use of Vectran fiber was for demanding and specialized for military applications. The unique properties of this high-performance Fiber satisfy many of the militaries and aerospace needs of today.
Recreation and leisure
Vectran fiber is an excellent option for recreation and leisure. Products such as sailcloth, reinforced hulls, fishing poles, and lines, Golf gloves, etc.
Industrial applications
Vectran fiber brings unique solutions to industrial applications. Stability to most chemicals allows the manufacture of chemically
Conclusion:
The Vectran fiber is 7-8 times stronger than stainless steel by knowing the specific length. The initial modulus is also high as compared to stainless steel. By identifying some properties we know that the property of Vectran is the same as Kevlar. The abrasion resistance of Vectran is excellent. As the temperature goes below (sub 0) the Vectran fiber increases its strength. Vectran is having very good resistance to organic and inorganic solvents.
References:
- Yuxi Liu a, Yuyan Liu et.al,
“Structural evolution and
degradation mechanism of Vectran fibers upon exposure to
UV-radiation”, Department of Polymer Materials
and Engineering, Harbin Institute of Technology, Harbin 150001, China
- Russell
B. Fette, Marjorie F. Sovinski, “Vectran
Fiber Time Dependent Behavior and Additional Static Loading Properties”.
- Vectran: Development of high-functionality Fiber and its application of Kuraray co., Ltd. Keisuke Hori Yusuke Hoshino Hiroshi Shimizu
- Vectran.Wikipedia
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