The nature of polymeric materials

Life depends fundamentally on organic polymers. These polymers provide not only food but also clothing, shelter and transportation.

Indeed nearly all the material need of man could be supplied by natural organic products. The list of these materials and things made of them might be very long: wood, fur, leather, wool, cotton, silk, rubber, oils, papers, paints and so on. The organic polymers from which such things could be made include proteins, cellulose, starch, resins, and a few other classes of compounds.

Modern methods of physical and chemical analyses have uncovered the principles that govern the properties of the natural polymers. On the basis of the discovery involved a new industry of man-made organic polymers has appeared. One could list the principal products: such as fibers, synthetic rubbers, coatings, plastics. Plastics and synthetic coating are already in common use.

Synthetic polymers now available already possess several of the properties required in a structural material. They are light in weight, easily transported, easily repaired, highly resistant to corrosion and solvents, and satisfactorily resistant to moisture. It would be necessary to add that they have long-lived durability and resistance to high temperatures. A very important question could arise whether synthetic polymers could be made inexpensive enough to compete with the structural materials such as metals and ceramics. The answer could be – “yes”. The natural polymers such as proteins, cellulose and other dominated his existence and even in ancient times people used these materials.

Yet as late as at the end of the 19th century polymer chemistry got little attention. Chemists attacked sugar, glycerol, fatty acids, alcohol and other organic compounds. But only feeble efforts were made to investigate such common materials as wood, starch, wool, silk. The substances composing these materials couldn’t be crystallized from solution, nor could they be isolated by distillation.

It was only in the 20th century that the scientists began thorough investigation of these materials. Having used some powerful physical instruments, an electron microscope, viscometer, X-ray diffraction apparatus, they could have revealed the polymers in all their intricacy. Their molecules were very large, the molecular weights running as high as million units, whereas simple organic substances such as sugar and gasoline have molecular weight in the range of only about 50-500.

The giant molecules can be composed of a large number of repeating units. Most polymers have the form long, flexible chains. Having found out that, chemists began synthesizing artificial polymers. This has led to the establishment of industries producing synthetic fibers and numerous polymeric materials.