Synthetic Polymers—Cellulosics, Other Polysaccharides, Polyamides, and Polyimides

Abstract

Abstract This chapter will focus on cellulose and its derivatives, polyamides, such as nylon, and polyimides. Natural polymers are biological macromolecules and are as old as life itself. The natural polymers include such diverse materials as proteins, polypeptides, polysaccharides, DNA, RNA, wood, wool, and silk. The word polymer is derived from the Greek words poly, or many, and meros, or parts. Natural cellulose is mainly used to produce paperboard and paper. With various chemical treatments, many different types of modified cellulose are prepared. For example, cellulose gum, or sodium carboxyethylcellulose (CMC), is widely used as a cost‐effective thickener and stabilizer in food and beverages. In addition to modifying the behavior of water, cellulose gum is useful in modifying flow, adding texture, and enhancing mouthfeel. A wide range of cellulose gum grades with different viscosities, molecular weights, degrees of substitution, and particle sizes are used in food and beverages. Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk while artificially made polyamides are nylons and aramids. These synthetic polyamides are commonly used in textiles, automotive industry, home care, and sportswear due to their high durability and strength. Polyimide materials are lightweight, flexible, resistant to heat and chemicals, and are used in the electronics industry for flexible cables and as an insulating film. Due to the high mechanical stability even at elevated temperatures, polyimide materials are used as bushings, bearings, sockets, or constructive parts in demanding applications.