Polymers, hamari zindagi ka aham tareen hissa ban chukey hain,,, hamain shaid hi apney ird gird koi aisi cheez nazar aye,,, jis main bil-wasta ya bila-wasta polymers ka istamaal na hua ho. Yeah tu wo cheez khud polymers ki bani hui hon gi,,, ya unki processing main polymers use hue hon gey. Natural Polymers ki bari ta'adaad bhi hamari zindagi main shamil hey,,, lekin synthetic polymers ki ta'dad iss se kahin ziada hey

Ayee ham Polymers ki history,,, aur inki application ke barey main kuch daikhtey hain

Humanity has a long history of trying to understand the substance and structure of the physical world around us, whether by simple observation or experimental manipulation. In ancient Greece, for example, Aristotle concluded that all materials were made up of combinations of only four elements: air, earth, fire, and water. During the Middle Ages, alchemists tried in vain to convert common metals into gold. By the late eighteenth century, chemists had begun synthesizing and breaking down chemicals in an effort to determine their fundamental components. Early in the nineteenth centur y, English chemist John Dalton, observing that chemicals would combine only in specific ratios, concluded that matter was made of indivisible “atoms” (a concept first proposed by the Greek philosopher Democritus in about 400 BC). Nineteenth-century chemists also determined that it was possible to synthesize so-called organic compounds, once believed to be made only in living organisms , from inorganic chemicals.

Even as chemists pursued their investigations into the nature of nature, inventors were creating new materials by treating natural substances with various chemicals at elevated temperatures and pressures. In 1839, American inventor Charles Goodyear discovered a technique, which he called vulcanization, for manipulating the properties of the sap from rubber trees by treating it with heat and sulfur. The process converted a gummy, springy material used mainly to erase (“rub out”) into a dry, tough, elastic material that would make automobile tires possible—and eventually a transportation revolution.

Investigators working at the theoretical level were equally productive, arriving at a series of independent realizations that would eventually lay the foundation for the polymer industry. In 1858, German chemist Friedrich Kekulé developed the framework for understanding the structure of organic molecules when he showed that a carbon atom can form chemical bonds with up to four other atoms and that multiple carbon atoms can join together to create long chains—a discovery also made at about the same time by Scottish chemist Archibald S. Couper. Then, in 1874, Jacobus van’t Hoff of the Netherlands and Joseph Le Bel of France independently suggested that the carbon atom’s four bonds are arranged so that they point at the corners of a tetrahedron, or pyramid. Since carbon atoms are the framework for natural and artificial polymers, the two discoveries would in time furnish a three-dimensional picture of the molecular stru c t u re of polymers.

In 1870, four years before the structure of the carbon atom was elucidated, American inventor John Wesley Hyatt won a contest to find a material for billiard balls to replace ivory—then as now in short supply. Hyatt’s prize-winning contribution was celluloid, based on cellulose, a polymer that is the basic structural material of plant cell walls. It was the start of the polymer industr y. Hyatt treated cellulose nitrate, or guncotton—an explosive material made by exposing cotton plant fibers to nitric and sulfuric acids—with alcohol and camphor. What he got was a hard, shiny material that could be molded when hot. Cheap and uniform in consistency, this new material did indeed replace ivory in billiard balls. Occasionally though, when the celluloid billiard balls collided, they created a small detonation like a firecracker because of the explosive nature of cellulose nitrate, which is related to trinitrotoluene (TNT) in composition. Celluloid also replaced horn in combs, found wide use in housewares, and was made into the first flexible photographic film. In 1887, Count Hilaire de Chardonnet created a related product when he learned to spin cellulose nitrate into Chardonnet silk, the first synthetic fiber to enter production and a forerunner of rayon, nylon, and Dacron.