ABSTRACT
The microscope has played an important part in formulating structural concepts in polymeric materials. The light microscope (LM) provided information on the external structure of bulk and fibrillar polymers, and the transmission electron microscope (TEM) permitted ultrastructural information to be obtained. The scanning electron microscope produces surface images that are realistic, three-dimensional reproductions of the sample, and its depth of focus and range of magnifications fill the gap between the LM and the TEM. Mercerization, a process of swelling the fiber in a caustic solution, causes the wrinkled surface to become smoother and the fiber to become more cylindrical. This treatment changes the crystalline structure of the cellulose, and improves textile properties of the fiber. Treating cotton textiles with phosphorus-containing flame-retardant finishes reduces fabric flammability. When an untreated cotton fabric is burned under atmospheric conditions, it produces a wispy, fragile char.
