Recently there has been a drive to replace traditional engineering materials with polymeric solutions. Fiber reinforced polymers offer combine the inherent benefits of polymers such as light weight and anti-corrosion with high strength and stiffness to weight ratios. Polymers are highly viscoelastic meaning they have both elastic, solid, and viscous, fluid like behavior and their mechanical properties are time dependent. Dynamic mechanical analysis is a useful tool in measuring the viscoelastic behavior of materials, and glass transition in response to cyclic loading cycles. Each chapter in this work studies the dynamic mechanical behavior of a different class of polymer, from polyurethane thermosetting rubber, to polyester based thermoplastic elastomer, to high performance polyamide thermoplastic. In each case, novel composite materials have been developed and characterized by reinforcement with selective fibers which was found to significantly enhance the mechanical and thermal properties of the pure polymer.