Physical Structure of Cotton Fiber

Physical Structure of Cotton Fiber:
 i. Cuticle: The cuticle is the out side layer or the skin of the cotton fiber, which contains some cellulose but accompanied by fat and waxes.
ii. Primary wall: Under the cuticle is the primary cell wall composed of criss-crossed cellulose and also contains some pectin’s. The criss-cross pattern of cellulose confers peri-pherical strength of fiber.
iii. Secondary wall: The secondary wall constitutes the bulk of the cellulose component, which lies between the primary wall and lumen of the fiber. The secondary wall of a matured fiber is practically pure cellulose and probably represents about 90% of the fiber weight. It is composed of two layers. S1 and S2 with a thickness of about 100nm.
iv. Lumen: The innermost part of cotton fiber is a hollow cannel running the length of the fiber. It contains proteins, coloring matter and mineral deposited on its walls. Depending on the maturity of the fiber. The lumen varies in dimension over a range. Mature fiber may have so heavy deposition of cellulose in the secondary wall which results in developing the fiber. So fully as to leave a very little lumen at all. On the other hand an immature fiber may contains so little secondary cellulose that the lumen is wids and distinct.
Physical Structure of Cotton Fiber