Elastic moduli of polymer crystals for the chain axial direction

Abstract

Abstract Some experiments were carried out to prove the validity of the assumption of a simple series model for the calculation of the elastic modulus of crystalline regions in oriented linear polymers from X‐ray determination of lattice extension. Various specimens such as filaments, fibers, and films were prepared from polyethylene, polyvinyl alcohol, polypropylene, polyoxymethylene and cellulose, stress‐strain curves constructed under the assumption of a simple series model; and calculated values of modulus compared. In spite of the differences of microstructures of these specimens, nearly the same value for the lattice modulus was obtained for each polymer. A large difference of specimen moduli had no effect on the lattice modulus. Lattice moduli of dry and water‐swollen polyvinyl alcohols or cellulose did not differ from each other. These results are a strong support for the above assumption. Extensibility of various polymer molecules was also discussed.