Crystal deformation in aromatic polyesters

Abstract

A study has been carried out of the changes in the x‐ray diffraction patterns which occur when oriented fibers or tapes of poly(trimethylene terephthalate) (3GT) and poly‐(tetramethylene terephthalate) (4GT) are subjected to mechanical tensile stress. Although the polymers show very different behavior in detail, in both cases comparatively large reversible lattice strains are observed (∼ several %). The diffraction pattern of 3GT changes monotonically with increasing macroscopic strain, suggesting that the lattice responds immediately to the applied stress, and deforms as though it were a coiled spring. In 4GT, on the other hand, there is no detectable change in the x‐ray diffraction pattern at low macroscopic strains, i.e., low values of the applied stress. At higher stresses, changes in the pattern occur which suggest a definite change in the crystal structure. Finally at the highest values of applied stress, the lattice deformations cease to increase. A preliminary discussion is presented of the relationship of these x‐ray diffraction results to the mechanical stress–strain behavior.

Structure and Physical Properties of Naphthalene Containing Polyesters I. Structure of Poly(butylene 2,6-naphthalate) and Poly(ethylene 2,6-naphthalate) as Studied by Solid State NMR Spectroscopy

“…28, No. 2,1996 From estimation by both factors, the chemical shift changes ofC4a and C8a in going from undrawn to drawn PEN and PBN films may be affected by both factors. As the crystalline morphology revealed by electron microscopy is ill-defined for PBN than PEN, i.e., the polymer chain arrangement is less ordered in oriented PBN film than PEN, the chemical shift change ofPBN may be less than that of PEN.…”

Morphology and physical properties of poly(butylene terephthalate)

“…while crystal lattice deformation during stretching has been inferred from x-ray diffraction. 6 In addition, the effect of skin-core morphology has also been correlated with the fracture nature by Hobbs and Pratt?, and processing variables have been demonstrated to affect the rheological properties and impact ~trength.~ The effects of molecular weight, glass fiber length, and orientation on mechanical properties have also been studied by McNally and Freed. 8 The purpose of this paper is to investigate the effect of liquid nitrogen quenching and glass reinforcement on the morphology, degree of crystallinity, and dynamic mechanical properties of PBT.…”

Production of PBT/PC particle systems by wet grinding

“…Also X-ray diffraction and infrared spectroscopy prove that no pronounced structural changes occur: The diffractograms (Figure 3) of the feed material and wet ground PBT are almost identical. The patterns are typical for -PBT [12,13], no significant changes due to grinding occur. Infrared spectra of polymer powders obtained for different process times are depicted in Figure 4.…”