CONDITION EQUATION OF POLYMER FILAMENTS

Subject of Research. Studies of thermal and mechanical properties of polymer filaments and fibers are carried out. Refinements are made to the previously obtained constitutive equation that describes deformation-relaxation processes in polymer materials. The refinement gives the possibility to describe the thermoviscoelastic behavior of the studied materials in a wide range of temperatures and mechanical stresses, as well as to obtain and study the polymer filaments condition equation in case of a variable temperature. Method. The state of polymer filaments and fibers is researched on the basis of the barrier theory using the balance equation, and the constitutive equations are obtained for the cases of one and a number of energy barriers. A one-barrier equation of polymer material condition is obtained by the thermodynamics method of elastic rods with taking into account the current temperature and the coefficient of linear expansion. The general equation of a polymer material condition is given for the case of an arbitrary number of barriers. Main Results. The constitutive equation describing the thermoviscoelastic properties of polymer materials is modernized. The condition equation of polymer fibers and filaments is obtained. A relationship between the maximum shrinkage temperature and the coefficient of linear expansion has been established. The real modulus of elasticity is determined as a function of temperature. Practical Relevance. The paper illustrates the isometric heating method application for determination of the real modulus of elasticity as a function of temperature.