Mechanisms of Toughening

The basic mechanism of toughening is one of void formation and shear band formation (cavitation) when stress is applied. 

Kramer, E. J. Mechanisms of Toughening in Polymer Mixtures, in Polymer Compatibility and Incompatibility — Principles and Practices (ed. K. Sole), MMI Press, Midland, MI, 1982, p. 251... 

A New Mechanism of Toughening Glassy Polymers 5.1 Toughening Strategies... 

Dr. Riew has presented more than 50 technical papers and holds more than 25 patents on emulsion polymers, hydrophilic polymers, synthesis and application of telechelic polymers, and toughened plastics for adhesives and composites. His latest research is in the synthesis, characterization, and performance evaluation of impact modifiers for thermosets and engineering thermoplastics. His research interests include correlating polymer chemistry and physics, morphology, engineering, and static and dynamic thermomechanical properties to the failure mechanisms of toughened plastics. 

Investigations of Micromechanical and Failure Mechanisms of Toughened Thermoplastics by Electron Microscopy... 

To study the influence of these structural parameters on the micromechanical mechanisms of toughening, several techniques of electron microscopy were used. Electron microscopic techniques allow investigations not only of detailed morphology but also of the micromechanical processes of deformation and fracture (3, 9-11). 

Figure 17. Schematic representation of the three-stage mechanism of toughening in PA6 blends (a) elastic stress concentration, between particles and the for-...

Use has been made of the miscibility of polycarbonate and PMMA to assist in toughening poly(buiylaie terephthalate) with core-shell particles which have a PMMA shell [138]. By addition of a small amoimt 10 wt%) of polycarbonate, the immiscibility of PMMA and poly(butylene terephthalate) is overcome and good particle dispersions are achieved. The polycarbonate simply acts as an interfacial agent. The mechanism of toughening in this system has been studied... 

Fig. 35. Dependence of fracture energy on the modifier composition (CTBN 1300 X 9 = carboxyl-tenninated acrylonitrile, acrylic acid and butadiene rubber with 18% acrylonitrile and 2% acrylic acid contents CTBN 1300x 13 = carboxyl-terminated acrylonitrile, butadiene rubber with 26% acrylonitrile content) (Reprinted from Journal of Materials Science, 27, T.K. Chen, Y.H. Jan, Fracture mechanism of toughened epoxy resin with bimodal rubber-particle size distribution, 111-121, Copyright (1992), with kind permission from Chapman Hall, London, UK)...

The mechanism of toughening in particie-modified crazabie giassy poiymers... 

Mechanisms of toughening in ceramic matrix composites are discussed by Rice [236,237] and Marshall [238] deals with failure mechanisms in ceramic matrix composites. 

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