The mechanisms and mechanics of the toughening of epoxy polymers modified with silica nanoparticles

By T. Hsieh, A. Kinloch, Kunal Masania, A. C. Taylor, S. Sprenger. 2010

479 citations recorded by the source corpus.

Abstract The present paper considers the mechanical and fracture properties of four different epoxy polymers containing 0, 10 and 20 wt.% of well-dispersed silica nanoparticles. Firstly, it was found that, for any given epoxy polymer, their Young’s modulus steadily increased as the volume fraction, v f, of the silica nanoparticles was increased. Modelling studies showed that the measured moduli of the different silica-nanoparticle filled epoxy polymers lay between upper-bound values set by the Halpin–Tsai and the Nielsen ‘no-slip’ models, and lower-bound values set by the Nielsen ‘slip’ model; with the last model being the more accurate at relatively high values of v f . Secondly, the presence of silica nanoparticles always led to an increase in the toughness of the epoxy polymer. However, to what extent a given epoxy polymer could be so toughened was related to structure/property relationships which were governed by (a) the values of glass transition temperature, T g , and molecular weight, M c , between cross-links of the epoxy polymer, and (b) the adhesion acting at the silica nanoparticle/epoxy-polymer interface. Thirdly, the two toughening mechanisms which were operative in all the epoxy polymers containing silica nanoparticles were identified to be (a) localised shear bands initiated by the stress concentrations around the periphery of the silica nanoparticles, and (b) debonding of the silica nanoparticles followed by subsequent plastic void growth of the epoxy polymer. Finally, the toughening mechanisms have been quantitatively modelled and there was good agreement between the experimentally-measured values and the predicted values of the fracture energy, G c , for all the epoxy polymers modified by the presence of silica nanoparticles. The modelling studies have emphasised the important roles of the stress versus strain behaviour of the epoxy polymer and the silica nanoparticle/epoxy-polymer interfacial adhesion in influencing the extent of the two toughening mechanisms, and hence the overall fracture energy, G c , of the nanoparticle-filled polymers.

Subfields: Mechanical Engineering, Mechanics of Materials, Polymers and Plastics

View Paper: https://www.semanticscholar.org/paper/8ae2afcdc651121c8859371a9533020e5bf4f093

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Mechanical Engineering

1. S. Sprenger
2. R. Pethrick
3. A. Kinloch
4. A. C. Taylor
5. T. Hsieh
6. I. Kinloch
7. Kunal Masania
8. Zhong Zhang

In Mechanics of Materials

1. R. Pethrick
2. S. Sprenger
3. A. Kinloch
4. A. C. Taylor
5. T. Hsieh
6. Longcheng Tang
7. Kunal Masania
8. I. Kinloch

In Polymers and Plastics

1. S. Sprenger
2. R. Pethrick
3. A. Kinloch
4. A. C. Taylor
5. T. Hsieh
6. I. Kinloch
7. Longcheng Tang
8. Kunal Masania

Citations in the corpus

• The effect of carbon nanotubes on the fracture toughness and fatigue performance of a thermosetting epoxy polymer (2011, background): “Previous studies [38,55] have calculated the fracture energy contributed by the plastic void growth mechanism, which can be written as:”
• Fracture mechanisms of epoxy-based ternary composites filled with rigid-soft particles (2012, background): “[13,14] reported that the matrix shear band contributed more to the fracture toughness than the plastic void growth effect.”
• Design and ageing of adhesives for structural adhesive bonding – A review (2015, methodology): “Recently, Kinloch and Taylor et al.33,34 have explored the effects of the addition of nano silica to epoxy resin system.”
• Improving the Toughness and Electrical Conductivity of Epoxy Nanocomposites by using Aligned Carbon Nanofibres (2015, background): “For rubberand nanosilica-toughened epoxies, this plastic void growth mechanism has been shown to significantly increase the fracture toughness of the material [23,47].”
• The toughness of epoxy polymers and fibre composites modified with rubber microparticles and silica nanoparticles (2010, methodology): “Previous work using silica nanoparticles has shown that they can increase the toughness of epoxy polymers, and also increase their cyclic-fatigue performance [1,2].”
• Improving the fracture toughness and the strength of epoxy using nanomaterials--a review of the current status. (2015, background): “24 Low modulus rubber particles usually decrease the sti ff ness and thermal properties of polymer-based materials.”