FRICTIONAL PROPERTIES OF TEXTILE FIBRES
In this article, garment merchandising will discuss about FRICTIONAL PROPERTIES OF TEXTILE FIBRES. Friction is the force that resists the drive of a surface over another surface during sliding. When fibres are treated in textile industry, friction is established between them. Because of the friction, the properties revealed by textile fibres are known as frictional properties.
It is the surface property of the fibre when two solid surfaces slip against each other. When we discuss about fiber friction then it is very essential for it is the force that holds together the fibre in a spun yarn and the interlacing threads in a fabric. For example, if we scrub silk fabric with itself or any other type of material then static charge and heat energy is formed due to fiber friction.
There may be two types of fiber frictions-
- Fiber to Fiber friction that is amongst two same or different fibers.
- Fiber to Solid friction that is present in amongst fiber and solid particle or surface.
Types of Friction
There are two types of frictions-
It is the force that must be overwhelmed to initiate sliding of two objects or fibers in contact. It is self-governing of area of contact.
Kinetic or Dynamic friction:
It is the force that must be overwhelmed to continue slipping. It is self-governing of slipping speed, however in case of some semi crystalline polymers this behavior is very multifaceted. Kinetic friction is always lesser than that of static friction.
Factors Affecting the Frictional Intensity of Textile Materials
- Composition of the material (natural/synthetic)
- The state of the surface (slippery/rough surface)
- Weight of the fibre
- Pressure between two surfaces
- Area of contact or angle of contact
- Speed of sliding of one surface over another
- Temperature & Relative humidity (%)
- Water absorption of fibre
- Cross-sectional area of fibre
Directional Frictional Effect (DFE)
The friction of the wool fibre be governed by on the direction in which it is dragged. The resistance is greater when it is dragged against the scales than when it is dragged with the scales. This is called the directional frictional effect. So, in case of wool fibre it can be said that, less friction takes place amongst the fibres with the direction of scales and the friction becomes higher between the fibres against the scales.
Wool has more friction for having scales in its surface. But, cotton also has greater friction due to its convolution (natural crimp) and has more friction than wool.
Co-Efficient of Friction
Frictional intensity of textile fibres can be determined by measuring co-efficient of friction. According to Amonton’s basic law (2nd law) of friction, frictional force is proportional to the normal force between surfaces in interaction that is frictional force is proportional to the perpendicular force of a material due to its own weight.
So, F∞ N; where F= Frictional force & N= Normal or perpendicular force
Or, F= µ N
Or, µ= F/N
Here, µ is the proportionate constant known as co-efficient of friction. Thus, co-efficient of friction may also be define as the ratio between frictional force and perpendicular force of a material.
Frictional intensity of textile fibres be contingent on the difference between µs and µs (µs-µk), where µs is always higher than µk. If the variance is high, then the fabric becomes greasy and if the difference is less, then the fabric becomes uneven.
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