Lecture

Crazing in Glassy Polymers

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In course

MSE-360: Polymer science + TP

Introduction to polymer physics and the link between chemical structure and macroscopic properties, with emphasis on morphology and thermomechanical behaviour, polymer technology and manufacturing techniques, providing a basis for the rational selection of ...

Description

This lecture explores the phenomenon of crazing in glassy polymers, which are fine crack-like striations that can withstand significant stress loads and are precursors to failure. The microstructure of crazes, nucleation, propagation mechanisms, and the competition between crazing and necking are discussed. The lecture also covers the relationship between crazing and entanglement effects, the effect of molecular weight on craze formation, and strategies to reduce brittle behavior through rubber toughening. The importance of multiple crazes in dissipating energy and improving resistance to failure is highlighted, along with the role of elastomer particles in nucleating crazes. The lecture concludes by emphasizing the impact of entanglement density on craze strength and fracture resistance.

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Instructors (2)

John Christopher Plummer

ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE (EPFL), Lausanne, Switzerland 1989- Collaborateur Scientifique/Chargé de Cours (Lecturer) (1998-) Privat Docent (1998) Laboratoire de Technologie des Composites et Polymères (LTC) (2000-) Laboratoire de Polymères (LP) (1998-2000) UNIVERSITY OF MICHIGAN (UMICH), Ann Arbor, MI, USA 1995-1996 Visiting Scientist, Department of Materials Science and Engineering (DMSE) UNIVERSITY OF CAMBRIDGE, Cambridge, UK 1986-1989 Research Assistant, Physics and Chemistry of Solids Group (PCS), Department of Physics UNIVERSITY OF CAMBRIDGE, Cambridge, UK, Department of Materials 1986 PhD, "Flux Pinning in Type-II Superconductors" UNIVERSITY OF CAMBRIDGE, Cambridge, UK, 1982 BA/MA Honours Degree in Natural Sciences Awards Prix R&R Haenny, 2007, DuPont Research Award, 2003, Commendation, British Polymer Group, Reading 1989 RECENT PUBLICATIONS Ramier J, Da Costa N, Plummer CJG, Leterrier Y, Manson JAE, Eckert R, Gaudiana R, Cohesion and adhesion of nanoporous TiO2 coatings on titanium wires for photovoltaic applications, Thin solid films, 516, 1913 (2008). Ramier J, Plummer CJG, Leterrier Y, Manson JAE, Eckert B, Gaudiana R, Mechanical integrity of dye-sensitized photovoltaic fibers, Renewable energy, 33, 314 (2008).

Houphouet-Boigny C, Plummer CJG, Wakeman MD, Manson JAE, Hybrid glass fiber-reinforced thermoplastic nanocomposites, J. Thermoplast. Comp. Mater., 21, 103 (2008).

Ternat C, Ouali L, Sommer H, Fieber W, Velazco MI, Plummer CJG, Kreutzer G, Klok HA, Manson JAE, Herrmann, Investigation of the Release of Bioactive Volatiles from Amphiphilic Multiarm Star-Block Copolymers by Thermogravimetry and Dynamic Headspace Analysis, Macromolecules 41(19), 7079 (2008). Ruggerone, R., Plummer, C.J.G., Negrete Herrera, N., Bourgeat-Lami, E., Månson, J-EA, Mechanical properties of highly filled latex-based polystyrene/laponite nanocomposites, Solid State Phenomena Vol. 151, 30 (2009). Plummer, CJG, Dalle Vacche, S, Houphouët-Boigny, C, Michaud, V, Månson, JAE, Hybrid Glass Mat Reinforced Polypropylene-Montmorillonite Nanocomposites, Solid State Phenomena Vol. 151, 60 (2009). Ruggerone, R., Plummer, C.J.G., Negrete Herrera, N., Bourgeat-Lami, E., Månson, J-EA, Highly filled polystyrenelaponite nanocomposites prepared by emulsion polymerization, European Polm. J. 45, 621 (2009). Ruggerone, R., Plummer, C.J.G., Negrete Herrera, N., Bourgeat-Lami, E., Månson, J-EA, Fracture mechanisms in polystyrene/laponite nanocomposites prepared by emulsion polymerization, Engineering Fracture Mechanics 76, 2846 (2009) Clausen P., Andreoni W., Curioni A., Hughs E., Plummer C.J.G. Adsorption of low-molecular-weight molecules on the surface of a sodium smectite clay: an ab initio study, Journal of Physical Chemistry C 113, 12293 (2009). Clausen P., Andreoni W., Curioni A., Hughs E., Plummer C.J.G., Water adsorption on a sodium smectite clay surface: an ab initio study, Journal of Physical Chemistry C 113, 15218 (2009). Molberg, M, Leterrier, Y., Plummer, C.J.G., Walder, C., Löwe, C., Opris, D.M., Nüesch, F.A., Bauer, S., Månson, J.-A.E., Frequency dependent dielectric and mechanical behaviour of elastomers for actuator applications, J. Appl. Phys. 106, 054112 (2009) Clausen P., Signorelli M., Schreiber A., Hughes E., Plummer CJG, Fessas D., Schiraldi A., Månson E. J.-A., Equilibrium desorption isotherms of water, ethanol, ethyl acetate and toluene on a sodium smectite clay, Journal of Thermal Analysis and Calorimetry 98, 833 (2009) Micusik, M., Bonnefond, A., Reyes, Y., Bogner, A., Chazeau, L., Plummer, C.J.G., Paulis, M., Leiza, J.R., Morphology of Polymer/Clay Latex Particles Synthesized by Miniemulsion Polymerization: Modeling and Experimental Results Macromol. React. Eng. 2010, 4, 432 (2010). Houphouet-Boigny C., Plummer CJG, Vacche SD, Michaud V, Wakeman MD, Månson E. J.-A., Hybrid Glass Mat-reinforced Polypropylene-Montmorillonite Nanocomposites, J. Comp. Mater. 44, 1975 (2010). Delabarde, C., Plummer C.J.G., Bourban, P.-E., Månson E. J.-A., Solidification behavior of PLLA/nHA nanocomposites, Comp. Sci. & Tech. 70, 1813 (2010). Plummer C.J.G., Ruggerone R., Negrete-Herrera N., Bourgeat-Lami E., Månson J.-A.E., Small Strain Mechanical Properties of Latex-Based Nanocomposite Films, Macromol. Symp. 294, 1 (2010). Dalle Vacche, S., Plummer C.J.G., Houphouet-Boigny C., Månson E. J.-A., Morphology and mechanical properties of isotactic polypropylene glass mat thermoplastic composites modified with organophilic montmorillonite, J Mater Sci 46, 2112 (2011).

Official source

Related concepts (32)

Crazing

Crazing is the phenomenon that produces a network of fine cracks on the surface of a material, for example in a glaze layer. Crazing frequently precedes fracture in some glassy thermoplastic polymers. As it only takes place under tensile stress, the plane of the crazing corresponds to the stress direction. The effect is visibly distinguishable from other types of fine cracking because the crazing region has different refractive indices from surrounding material.

Quantum entanglement

Quantum entanglement is the phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state of the others, including when the particles are separated by a large distance. The topic of quantum entanglement is at the heart of the disparity between classical and quantum physics: entanglement is a primary feature of quantum mechanics not present in classical mechanics.

Polymer chemistry

Polymer chemistry is a sub-discipline of chemistry that focuses on the structures of chemicals, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules.

Fracture mechanics

Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture. Theoretically, the stress ahead of a sharp crack tip becomes infinite and cannot be used to describe the state around a crack. Fracture mechanics is used to characterise the loads on a crack, typically using a single parameter to describe the complete loading state at the crack tip.

Fracture toughness

In materials science, fracture toughness is the critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited. A component's thickness affects the constraint conditions at the tip of a crack with thin components having plane stress conditions and thick components having plane strain conditions. Plane strain conditions give the lowest fracture toughness value which is a material property.

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