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Your search keyword '"Vergelati, Caroll"' showing total 22 results
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22 results on '"Vergelati, Caroll"'

8. Polymers in Detergency

Author

Gauthier-Lafaye, Jean, primary, Gresser, Robert, additional, Guerin, Gilles, additional, Joubert, Daniel, additional, and Vergelati, Caroll, additional

Published
1999
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9. Thermo-mechanical properties and blend behaviour of cellulose acetate/lactates and acid systems: Natural-based plasticizers

Author

Guillaume Sudre, Yvan Chalamet, Camille Decroix, Vergelati Caroll, Ingénierie des Matériaux Polymères (IMP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Polymers and Plastics, Organic Chemistry, Plasticizer, Modulus, 02 engineering and technology, Dynamic mechanical analysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Miscibility, Cellulose acetate, 0104 chemical sciences, Solvent, chemistry.chemical_compound, Crystallinity, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical engineering, X-ray crystallography, Materials Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

This work brings together thermo-mechanical and structural information for plasticized cellulose acetate (CA) by lactates and octanoic acid. CA are processed with plasticizer due to their high Tg and their strong H-bonding network. We prepared CA / plasticizer blends by corotative twin screw extruder and by solvent casting methods. The study of the different relaxations and of the glassy zone modulus was performed by dynamic mechanical analysis (DMA). The miscibility range of cellulose acetate blends were identified by the analysis of the tan δ. Depending on the composition of the system, one or two transitions are noted, this last result indicates the presence of a phase rich in CA and another in plasticizer. To connect this information to crystallinity and molecular organization, X-ray diffraction analyses were carried out. The disappearance of crystallinity allows the plasticization of previously inaccessible zones, causing a glassy modulus drop of more than 1000 MPa.

Published
2020

11. Damage Mechanisms of Plasticized Cellulose Acetate under Tensile Deformation Studied by Ultrasmall-Angle X-ray Scattering

Author

Charvet, Agathe, Vergelati, Caroll, Sotta, Paul, and Long, Didier R.

Abstract

We consider the microscopic mechanisms of damaging in plasticized cellulose acetate under tensile stress. We show how they appear and develop during the course of deformation until failure. By using scanning transmission electron microscopy, we observe the presence of cavities and the coexistence of homogeneous and fibrillar crazes. Ultrasmall-angle X-ray scattering experiments allow for describing the onset of damaging and the growth of crazes and for measuring the volume fractions of damages as well as their shapes and sizes at different stages during deformation. We propose that damages are initiated by the nucleation of cavities in the vicinity of pre-existing impurities. We then show that their initial growth after nucleation is blocked at a size of order 100 nm by strain hardening in their immediate vicinity where deformation and stress are amplified. Increasing the stress further leads to a new growth regime for a small fraction of crazes. Ultimate failure is due to the propagation of this small number of crazes and not to the accumulation of crazes and a coalescence process. We propose that this growth process is the consequence of homogeneous nucleation of new cavities just in front of existing ones. The volume fractions of damage remain very low, of order of 10–4at failure. The strain hardening behavior appears to be the key for preventing an early failure of the material and conferring high ductility to the material.

Published
2024
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