APPLICATIONS OF X-RAY-INVESTIGATIONS OF POLYMERS UNDER LOAD .1. MEASUREMENTS OF WAXS REFLECTIONS SHIFTS INDUCED BY ELASTIC STRETCHING OF ORIENTED POLYMER SYSTEMS ALONG THEIR ORIENTATION AXIS

What information can be obtained by wide-angle x-ray scattering (WAXS) from elastic deformation of oriented polymer systems along their orie ntation axis? This article is a critical review and some generalizatio n of answers for this question. Different cases are analyzed that occu r in practice or that might occur in the future: (1) determination of Young's moduli E-c of crystalline lattices parallel to the polymer cha ins and establishment of correlations between E-c and chain conformati on in crystalline lattices; (2) estimation of elastic properties of di fferent fragments of polymer chains, especially of multiatomic complex fragments; (3) detection of conformational polymorphism in crystallin e lattices; (4) determination of Poisson's coefficients of crystalline lattices; (5) estimation of potential ability of a given polymer for formation of systems with high moduli; (6) estimation of structural in homogeneity of amorphous polymers; (7) study of interaction character of structural elements in oriented polymer blends; (8) investigations of systems with a combination of extended and folded-chain crystals; ( 9) study of influence of cross-linking on structure-mechanical behavio r; (10) estimation of adhesive interaction of different components in polymer composites. Only Points 1 (see, e.g., Refs. 1-18) and 4 [19] h ave been considered in earlier literature by other authors, mainly for soft-chain polymers. Thus, similar results are considered here only b riefly, and primary attention is focused on the peculiarities of inves tigations of rigid-chain polymers. As for the other points, they were considered earlier in our separate works [20-38] (or have not been con sidered at all) and up to now have not received wide acceptance. Durin g the consideration here, both series and parallel models of interacti ons of different structural elements were used.