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Briefly describe how Kevlar is made. In your answer, be sure to discuss what type of polymer it is and the reactions showing how it is assembled. KevlarTM is a synthetic polymer that belongs to the aramid family. It is made through a polymerization reaction involving a monomer called para-phenylenediamine (PPD) and terephthaloyl chloride (TCl). The reaction between PPD and TCl forms a polyamide chain, which is the basis of Kevlar's structure. This reaction is known as a condensation polymerization reaction. The first step in the synthesis of Kevlar involves the reaction between PPD and TCl in a solvent, typically a mixture of N-methylpyrrolidone (NMP) and calcium chloride (CaCl2). This reaction takes place at a temperature of around 0-5 degrees Celsius. The PPD and TCl molecules react with each other, forming amide linkages and releasing hydrochloric acid (HCl) as a byproduct. The resulting polymer chain is then dissolved in a solvent and spun into fibers through a process called wet spinning. In this process, the polymer solution is extruded through a spinneret into a coagulation bath, which contains a liquid that causes the polymer to solidify. This coagulation bath is typically an aqueous solution of sulfuric acid (H2SO4) or a mixture of sulfuric acid and water. As the polymer solution enters the coagulation bath, the solvent evaporates, and the polymer chains align to form fibers. These fibers are then washed, dried, and stretched to improve their strength and orientation. The stretching process, also known as drawing, aligns the polymer chains further, increasing the intermolecular forces and enhancing the mechanical properties of the fibers. The resulting Kevlar fibers are extremely strong and have a high tensile strength. They are widely used in various applications, including body armor, ropes, cables, and protective clothing, due to their exceptional strength-to-weight ratio and resistance to impact and abrasion.
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It is made through a process called polymerization, which involves the reaction of monomers to form a long chain polymer. The monomers used to make Kevlar are 1,4-phenylene-diamine (also known as p-phenylenediamine or PPD) and terephthaloyl chloride (TPC). The Show more…
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Adi S.
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