Things you don’t know: Nine ways to identify fibers_Composite Fabric_Lamination Fabric_Soft Shell Fabric

IntroductionWith chemical fiber With the rapid development, fiber varieties are becoming increasingly diverse. In addition to general fibers, many new varieties such as special fibers, composite...

Introduction

With chemical fiber With the rapid development, fiber varieties are becoming increasingly diverse. In addition to general fibers, many new varieties such as special fibers, composite fibers, and modified fibers have appeared. In order to facilitate production management and product analysis, scientific identification of textile fibers is required.

Fiber identification includes identification of morphological characteristics and identification of physical and chemical properties.

Microscopic observation is commonly used to identify morphological characteristics.

There are many methods for identifying physical and chemical properties, including combustion method, dissolution method, reagent coloring method, melting point method, specific gravity method, Birefringence method, X-ray diffraction method and infrared absorption spectroscopy method, etc.

1. Microscope observation Law

Using a microscope to observe the longitudinal and cross-sectional morphology of fibers is the basic method for identifying various textile fibers. It is commonly used to Identify the broad categories of fibers. Natural fibers each have a special shape that can be correctly identified under a microscope. For example, cotton fiber is in the shape of a flat belt longitudinally with natural twists, and its cross-section is round in shape with a middle cavity. The wool has longitudinal curls, scales on the surface, and a round or oval cross-section. Some wool has pith in the middle. Jute has horizontal knots and vertical lines longitudinally, a polygonal cross-section, and a large central cavity.

Table 1 Morphological characteristics of various fibers

Fiber type	Vertical shape	Sectional shape
Tencel fiber	smooth	More regular circles or ovals, With skin-core layer
Modal fiber	There are 1 to 2 grooves in the longitudinal direction	Irregular, similar to a round waist, smoother, with a leather core
Soy fiber	Irregularities on the surface Grooves and island bumps	flatten Dumbbell-like shape and round waist
Bamboo fiber	There are grooves on the surface	Zigzag type, with skin and core layer
Chitin fiber	There are obvious grooves on the surface	Zigzag edges, obvious small gaps in the core
Viscose fiber	There are grooves on the surface	Zigzag type, with skin and core layer
Cotton fiber	Has natural twist	Round waist, with middle cavity
Silk	Surface smooth	Irregular triangle
Wool fiber	Square on the surface	circle
Polyester fiber	Stick-shaped	Smooth round surface

2. Combustion method

One of the common methods to identify natural fibers. Due to the different chemical compositions of fibers, the combustion characteristics are also different. It can be based on the difficulty of burning the fiber, whether it is thermoplastic, the smell produced during burning and the aftermath of burning. Characteristics of ash distinguish cellulose fibers and protein fibers. Cellulose fibers such as cotton, linen, and viscose burn quickly when in contact with flames and continue to burn after leaving the flame. There is a smell of burning paper and a small amount of soft gray ash is left after burning; wool and Protein fibers such as silk burn slowly when exposed to flames, and continue to burn slowly after leaving the flames. They smell like burned feathers and leave behind crispy black ash after burning.

Table 2 Characteristics of various fibers during and after combustion

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Fiber type	Close to the flame	In flames	Leave the flame	Burning smell	Residue form
Tencel fiber	Does not melt or shrink	Burn quickly	Keep burning	Burned paper smell	grey black gray
Modal fiber	Does not melt or shrink	Burn quickly	Keep burning	Burn paper smell	grey black gray
Soy protein fiber	Shrink	It does not melt when burning, but has black smoke

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