X-ray study of microstructure of slightly plasticized poly-(vinylchloride) (PVC)

Abstract

Small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) as well as transmission electron microscopy (TEM) techniques have been applied to investigate the microstructure of a number of commercial poly-(vinylchloride) (PVC) samples, stretched 200 % and annealed for 1 h at 110 ~ From SAXS analysis, the microstructure is described as an ensemble of quasi-spherical particles one-dimensionally ordered (in the fiber axis direction) and with large distance fluctuations in the equatorial plane. The superstructure is described as fibriUar or nematic-like. TEM micrographs confirm the SAXS data.SAXS meridional patterns present 001 and 003 reflections of Ca-stearate added as stabilizer to the samples, while WAXS profiles do not show any crystalline reflection of Castearate.An interaction of Ca-stearate molecules with PVC chains is postulated, which could partially account for the phenomenon called "antiplasticization" of PVC.

Analytical Methods

“…• film cast from solution, [1][2][3][4] • polymer solution, 5,6 • powdered polymer, 7 • blend of polymer with other ingredients, 8 • extruded specimen, [9][10][11] • plastisol spreading and thermal curing, 12 • compression molded sheet, 7,9,13 • calendered sheet, 14 • twin-roll milling, 7,13,15 • cutting from manufactured product, [16][17][18] • plastograph mixing, 19 • IR die pellets. 20 The form of the specimen depends in the first place on the analytical method used in the course of studies.…”

“…263 Also, secondary ion mass spectrometry, SIMS, was used in PVC membranes to determine the presence of metal cations to which SIMS is very sensitive. 12,14,[265][266][267][268] The crystallite size was estimated to be 6.5 nm 12 or in the range from 4 to 6.5 nm. 12,14,[265][266][267][268] The crystallite size was estimated to be 6.5 nm 12 or in the range from 4 to 6.5 nm.…”