Multiscale morphology and thermo‐mechanical history of poly(vinyl chloride) (PVC)

Abstract

The multiscale morphology of rigid poly(vinyl chloride) (PVC) formulations (in the nanometre to the micrometre range) was investigated by high resolution scanning electron microscopy, ultra‐small‐, small‐ and wide‐angle X‐ray scattering, as a function of thermo‐mechanical history. It has been shown that the hierarchical structure of PVC grains, when in the dry blend, disappeared during gelation that combines mechanical stress (ie shear stress and hydrostatic pressure) and heating. Nevertheless, the memory of the presence of the smallest particles (domains with diameters of about 80 nm) containing dense amorphous PVC and nanoscaled crystallites, has been highlighted by the study of the change of the microstructure when PVC was reprocessed with high mechanical deformation at a lower temperature than the previous gelation temperature. As a result, the main phenomena occurring during gelation were, in a first step, the disappearance of the hierarchical structure of the grains and, in a second step, the inter‐diffusion of the chains across the frontiers of the primary particles (mechanically reversible), but maintaining the domain structure. The crystalline microstructure was affected by thermo‐mechanical history, but the gelation level should not be estimated strictly in relation to the crystalline morphology. Copyright © 2004 Society of Chemical Industry

Melting, crystallization and optical behaviors of poly (ethylene terephthalate)-silica/polystyrene nanocomposite films

“…When PET is annealed between its glass transition temperature (T g ) and its melting temperature (T m ), it forms multiple size crystallites [21,22]. The smaller crystallites first melts on the surface of the bigger ones, and then the bigger crystallites melt gradually.…”

Analytical Methods

“…264 10.5.13 X-RAY ANALYSIS 10.5.13.1 Small angle x-ray scattering, SAXS Because PVC is a semi-crystalline material with low crystallinity, it is difficult to study it by x-ray analysis, therefore only infrequent contributions are published on the subject. 265 The same range was also determined for semi-crystalline intervals. 265 The same range was also determined for semi-crystalline intervals.…”

“…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.…”

“…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. 265 The microstructure of stretched films was described as an ensemble of quasi-spherical particles one-dimensionally ordered and with large distance fluctuations in the equatorial plane. 265 The microstructure of stretched films was described as an ensemble of quasi-spherical particles one-dimensionally ordered and with large distance fluctuations in the equatorial plane.…”

Determination of the aging mechanism of single core cables with PVC insulation

“…8a) should be larger due to the large concentration of carbon in the stabilizer. Although it is well known that PVC has multiscale morphology and possesses some microcrystalline domains [14], X diffraction analyses have not allowed concluding on the structural origin and on the crystallinity of these PbCl 2 clusters. However, their colour and regular shape suggest that it is an organized matter.…”