Microscopic Examination for Fiber Identification

  

•  For fiber analysis, microscope is one of the most powerful tools, to see the surface characteristics and cross-sectional shape of the fibers.

 Equipment:-

•  A microscope of good quality, with magnification from 100 to 450 diameters.
• Supplemental requirements are: number of regular glass microscope slides and cover glasses, a dozen or more small glass bottles fitted with medicine droppers, pair of fine pointed tweezers, dissecting needle, a micro-tome of cross-section block, razor blades, and a light source.

Manipulation:-

• The most important step in the microscopic examination is preparation of the slide.
• Fibers to be examined should first be degreased by washing in petroleum ether or carbon tetrachloride.
• After drying the fibers on a piece of blotting paper, they are transferred to the microscope slide.

ð  For longitudinal View:-

·     Cut the fibers into short lengths, not over 1/8”, and place them in a flask containing either water to which a little wetting agent has been added or ethyl alcohol.

·     Fibers are mounted on glass plate with mounting medium and covered with cover glass.

ð  For Cross sectional View:-

·     The simplest method of preparing cross sectional view is the cross section plate. This is a stainless steel plate, the size and shape of microscope slide with two rows of five holes each drilled in it.

·     One row has holes 1/32” in diameter, the other 1/64” in diameter.

·     The projecting fibers through the plate are cut off flush with the surface of the plate with a sharp razor blade.

·      Fibers are mounted on glass plate with mounting medium and covered with cover glass.

Table:- Microscopic View of Fibers

Fiber	Longitudinal View	Cross sectional View
Cotton	A flattened, collapsed, spirally twisted tube with a rough surface, and frequent convolution that change direction	Flat, elongated or bean shaped with lumen as a line or oval parallel to the larger direction
Viscose	Uniform diameter with striations running parallel to the fiber axis	Roughly circular or irregular in cross-section with separated or scalloped edges according to the process used
Wool	Irregular and roughly cylindrical, prominent scale margins or flattened plates	Oval to circular with variation in diameter. Medulla is concentric and variables in size
Silk	Flat irregular ribbons, twisted and with longitudinal striations	Very elongated triangles normally separated, with round corners
Nylon 66	Very regular, rod like	Circular
Nylon 6	Very regular, rod like	Circular
Polyester	Very regular, rod like	Circular

Reference: 

Textile Testing and Analysis by N A Vaishnav and H D Joshi, Popular Prakashan