Fibers play an important role in the textile industries, with natural fibers usually having low tensile strength, high moisture absorption, variable quality, low durability, and so on. Synthetic fibers have gained preference over the natural fibers in certain applications. The objective of this polymer design problem is to identify polymer repeat units that can serve as synthetic fibers, avoiding some of the disadvantages of natural fibers. Find target values for the following property needs: moisture (water) absorption; tensile strength; and temperature effect (ease of ironing or pressing depends on the relative position of the glass-transition temperature) among others. Generate the polymer repeat unit structures of nylon and check whether the property needs are satisfied.