Particle cavitation in rubber toughened epoxies: the role of particle size

Guild, FJ; Kinloch, A. J.; Taylor, A. C.

doi:10.1007/s10853-010-4447-y

Cited by 49 publications

(30 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are several reasons that may cause this. The lack of plastic deformation of the epoxy could be a direct result of the lack of strain energy build up due to such early debonding, thus slowing the growth of shear bands and voids [44,45]. Alternatively, these high aspect ratio GNPs have sharp edges which effectively act as defects and leads to fracture at low loads, hence low fracture toughness.…”

Section: Discussionmentioning

confidence: 99%

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

2016

Self Cite

View full text Add to dashboard Cite

Graphene has the potential to act as a high-performance reinforcement for adhesives or fibre composites when combined with epoxy polymer. However, it is currently mostly available not as single high aspect ratio sheets but as graphene nanoplatelets (GNPs), comprised of stacks of graphene sheets.Graphene nanoplatelets of a range of lateral size, thickness, aspect ratio and surface functionality were used to modify an anhydride cured epoxy polymer.The morphology, mechanical properties and toughening mechanisms of these modified epoxies were investigated. The GNPs were sonicated in tetrahydrofuran (THF) or n-methyl-pyrrolidone (NMP) to facilitate dispersion in the epoxy. The use of THF resulted in large agglomerates, whereas more finely dispersed stacks of GNPs were observed for NMP. The maximum values of modulus (3.6 GPa at 1 wt%) and fracture energy (343 J/m 2 at 2 wt%) were * Corresponding author, Tel.: +44 20 7594 7149Email address: a.c.taylor@imperial.ac.uk (A. C. Taylor) April 11, 2016 measured for the epoxy modified with an intermediate platelet size of approximately 4 µm, compared to 2.9 GPa and 96 J/m 2 respectively for the unmodified epoxy. The Young's modulus was highly dependent on the dispersion quality, whereas the fracture energy was independent of the degree of GNP dispersion. The larger agglomerates of the GNPs which were dispersed in THF toughened the epoxy by crack deflection, whereas the GNPs dispersed in NMP showed platelet debonding, pull-out and plastic void growth of the epoxy. This work indicates that reinforcement and toughening can be achieved at much lower contents than for conventional modifiers. Further, achieving a good dispersion is crucial to the engineering application of these materials, and intermediate-sized graphene achieves the best balance of properties. Preprint submitted to Journal of Materials Science

show abstract

Section: Discussionmentioning

confidence: 99%

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Rey et al [45] have pointed out that this is approximately -60°C for the polysiloxane found in the CSR particles in the current work. This increase in the cavitational resistance of the particles limits the dissipation of energy via the plastic void growth mechanism, although computational studies by Guild et al [46] have demonstrated that rubber particles cavitating at higher strains cause a far more complex shear-band dissipation mechanism and this can offset the loss of effectiveness of the void growth mechanisms. Finally, the increased resistance to plastic deformation of the matrix at the lower temperature limits the dissipation of energy via plastic deformation of the epoxy polymer.…”

Section: Fracture Propertiesmentioning

confidence: 99%

Toughened carbon fibre-reinforced polymer composites with nanoparticle-modified epoxy matrices

et al. 2016

Self Cite

View full text Add to dashboard Cite

In the current work, the microstructure and fracture performance of carbon fibre-reinforced polymer (CFRP) composites based upon matrices of an anhydride-cured epoxy resin (formulated with a reactive diluent), and containing silica nanoparticles and/or polysiloxane core-shell rubber (CSR) nanoparticles, were investigated. Double cantilever beam tests were performed in order to determine the interlaminar fracture energy of the CFRP composites, while the single-edge-notched bend specimen was employed to evaluate the fracture energy of the bulk polymers. The fracture energy of the bulk epoxy polymers increased from 173 J/m 2 for the unmodified polymer to a maximum of 1237 J/ m 2 with the addition of 16 wt% of CSR nanoparticles. The toughening mechanisms were identified as (a) localised plastic shear yielding and (b) cavitation of the CSR particles followed by plastic void growth of the matrix. The steady-state propagation value of the interlaminar fracture energy of the CFRP composites increased with increasing nanoparticle concentration, from 1246 J/m 2 for the unmodified epoxy matrix to a maximum of 1851 J/m 2 with 4 wt% of silica nanoparticles and 8 wt% of CSR nanoparticles. Crack growth in the CFRP composites was dominated by fibre-bridging toughening mechanisms. The efficiency of the transfer of toughness from the bulk polymers to the carbon fibre composites was considered. The measured fracture energy of both bulk and composite materials decreased at a test temperature of -80°C, compared with room temperature, i.e. 20°C. Nevertheless, the toughening effects of both the silica and CSR nanoparticles on the bulk epoxy polymers and the CFRP composites, compared with the unmodified epoxy polymers, were still evident even at the lower temperature. Indeed, the toughening effect of the silica nanoparticles was greater at -80°C than at room temperature.

show abstract

“…Nevertheless, computational studies by Guild et al [45] have demonstrated that rubber particles cavitating at higher strains cause a far more complex shear-band dissipation mechanism and this can offset the loss of effectiveness of the void growth mechanisms.…”

Section: The Bulk Epoxy Polymersmentioning

confidence: 99%

Simultaneously tough and conductive rubber–graphene–epoxy nanocomposites

2016

View full text Add to dashboard Cite

Abstract:In the current work the microstructure and fracture performance of carbon-fibre reinforced polymer (CFRP) composites based upon matrices of an anhydride-cured epoxy-resin (formulated with a reactive diluent), and containing silica nanoparticles and/or polysiloxane core-shell rubber (CSR) nanoparticles, were investigated. Double cantilever beam tests were performed in order to determine the interlaminar fracture energy of the CFRP composites, while the single edge-notched bend (SENB) specimen was employed to evaluate the fracture energy of the bulk polymers. The fracture energy of the bulk epoxy polymers increased from 173 J/m 2 for the unmodified polymer to a maximum of 1,237 J/m 2 with the addition of 16 wt% of CSR nanoparticles. The toughening mechanisms were identified as (a) localised plastic shear yielding and (b) cavitation of the CSR particles followed by plastic void growth of the matrix. The steadystate propagation value of the interlaminar fracture energy of the CFRP composites increased with increasing nanoparticle concentration, from 1,246 J/m 2 for the unmodified epoxy matrix to a maximum of 1,851 J/m 2 with 4 wt% of silica nanoparticles and 8 wt% of CSR particles. Crack growth in the CFRP composites was dominated by fibre-bridging toughening mechanisms. The efficiency of the transfer of toughness from the bulk polymers to the carbon fibre composites was considered. The measured fracture energy of both bulk and composite materials decreased at a test temperature of -80°C, compared with room temperature. Nevertheless, the toughening effects of both the silica and CSR nanoparticles on the bulk epoxy polymers and the CFRP composites, compared with the unmodified epoxy polymers, were still evident even at the lower temperatures. Indeed, the toughening effect of the silica nanoparticles was greater at relatively low test temperatures than at room temperature.

show abstract

Particle cavitation in rubber toughened epoxies: the role of particle size

Cited by 49 publications

References 32 publications

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

Toughened carbon fibre-reinforced polymer composites with nanoparticle-modified epoxy matrices

Simultaneously tough and conductive rubber–graphene–epoxy nanocomposites

Contact Info

Product

Resources

About