Improving the fracture toughness and the strength of epoxy using nanomaterials – a review of the current status

Abstract

The incorporation of nanomaterials in the polymer matrix is considered to be a highly effective technique to improve the mechanical properties of resins. In this paper the effects of the addition of different nanoparticles such as single-walled CNT (SWCNT), double-walled CNT (DWCNT), multi-walled CNT (MWCNT), graphene, nanoclay and nanosilica on fracture toughness, strength and stiffness of the epoxy matrix have been reviewed. The Young's modulus (E), ultimate tensile strength (UTS), mode I (GIC) and mode II (GIIC) fracture toughness of the various nanocomposites at different nanoparticle loadings are compared. The review shows that, depending on the type of nanoparticles, the integration of the nanoparticles has a substantial effect on mode I and mode II fracture toughness, strength and stiffness. The critical factors such as maintaining a homogeneous dispersion and good adhesion between the matrix and the nanoparticles are highlighted. The effect of surface functionalization, its relevancy and toughening mechanism are also scrutinized and discussed. A large variety of data comprised of the mechanical properties of nanomaterial toughened composites reported to date has thus been compiled to facilitate the evolution of this emerging field, and the results are presented in maps showing the effect of nanoparticle loading on mode I fracture toughness, stiffness and strength.

Experimental Studies of Stiffness Degradation and Dissipated Energy in Glass Fibre Reinforced Polymer Composite under Fatigue Loading

“…Delamination is a serious detriment to the stiffness and compressive load carrying capability of a FRP composite laminate [3,4] and this area has been investigated for new advanced nanomaterial to enhance the fracture toughness of FRP materials [5]. Manjunatha et al [6] studied the stress-controlled constant amplitude tensile fatigue tests at stress ratio R=0.1 on rubber modified GFRP composites.…”

Improving the fracture toughness properties of epoxy using graphene nanoplatelets at low filler content

“…[31][32][33][34] Low fracture toughness is one of the key drawbacks preventing the increased use of epoxies for a wider range of applications, and consequently toughening of epoxy resins has been at the forefront of many research studies since the early 1980s. 2,35,36 A common approach to increasing the toughness is the addition of a second-phase filler to the matrix at the micro-or nanoscale, resulting in composite materials which exhibit high specific strength and stiffness, and high fracture toughness. 2 The key objective of reinforcing epoxies is to allow the desired properties to be tailored according to the engineering needs while keeping the cost low.…”

“…18 The ability to improve the strength and fracture toughness of epoxy with the addition of GNPs at low loading content is a route undertaken by many researchers to face the engineering challenges of producing strong, lightweight materials. 2,10,19,20 Epoxy resins are widely used for many engineering applications, from composite wind turbine blades in the renewable energy sector to the highly complex structural parts for aircraft. [20][21][22] Developed in 1960s, the diglycidyl ether of bisphenol A (DGEBA) resin system is the most commonly used epoxy.…”

“…[1][2][3][4][5] Graphene nanoplatelets (GNPs) are regarded as short stacks of less than 10 graphene layers, and may be purchased at a relatively low cost. 2,[6][7][8] GNPs are widely used as nanoadditives for advanced composites, 1,9-11 electrodes in advanced batteries 12 and ultra/super capacitors, 13,14 and the conductive component in specialty coatings 15 or adhesives. 16 GNPs are also used for exceptionally strong and impermeable packaging, better lubricants, 17 and for highly sensitive strain sensors.…”

Self-lubricating, wear resistant protic ionic liquid-epoxy resin

“…The development of new polymer nanocomposites for tribological applications [1][2][3][4][5][6][7][8][9][10] is one of the fields of research in materials science and technology which has attracted more interest during the last years. Room-temperature ionic liquids (ILs) [11,12] contain bulk organic cations and organic or inorganic anions and show a unique combination of properties such as their low volatility, non-flammability, and their high thermal stability which are most relevant for tribological applications.…”