Book excerpt: This book covers the theory of the strength of laminated and reinforced structures made of polymer materials with regard to the changeability of physico-chemical properties is examined. It presents an experimental-theoretical method on the definition of physico-mechanical properties of polymers composite materials and polymerized bundles made of fibers with emphasis on the changes of physico-chemical properties of the materials. With mathematical strictness, the experimental and theoretical studies presented here will aid in the development of reliable methods and new practices of analyzing structures with the influence of chemically aggressive liquids and gases and in the creation of specific production structures that will withstand corrosive environments.