Functionalized graphene sheets for polymer nanocomposites

Abstract

Polymer-based composites were heralded in the 1960s as a new paradigm for materials. By dispersing strong, highly stiff fibres in a polymer matrix, high-performance lightweight composites could be developed and tailored to individual applications. Today we stand at a similar threshold in the realm of polymer nanocomposites with the promise of strong, durable, multifunctional materials with low nanofiller content. However, the cost of nanoparticles, their availability and the challenges that remain to achieve good dispersion pose significant obstacles to these goals. Here, we report the creation of polymer nanocomposites with functionalized graphene sheets, which overcome these obstacles and provide superb polymer-particle interactions. An unprecedented shift in glass transition temperature of over 40 degrees C is obtained for poly(acrylonitrile) at 1 wt% functionalized graphene sheet, and with only 0.05 wt% functionalized graphene sheet in poly(methyl methacrylate) there is an improvement of nearly 30 degrees C. Modulus, ultimate strength and thermal stability follow a similar trend, with values for functionalized graphene sheet- poly(methyl methacrylate) rivaling those for single-walled carbon nanotube-poly(methyl methacrylate) composites.

Interphases in Graphene Polymer‐based Nanocomposites: Achievements and Challenges

“…Here, increments in the Young's modulus and ultimate strengths of 80% and 20% respectively, were reported at 0.1% w/w loading. [ 60 ] This result demonstrated the ability of FGS to interact with polar polymers for creating a percolated interphase in which the properties of the host polymer matrix were substantially altered.…”

“…Only few articles report T g values of PGNs. It has been recently observed, [ 60 ] an spectacular increase in T g of 30 ° C in PMMA with only 0.05 wt% FGS, and of 46 ° C in poly(acrylonitrile) loaded with 1% wt FGS. These results were attributed to: a) the FGS wrinkled morphology that enhances mechanical interlocking with the polymeric chain and, therefore, a better interfacial adhesion, and b) the presence of oxygenated groups on graphene surface which may form hydrogen bonds with the carbonyl groups of acrylic polymers such as PMMA.…”

Improved Adhesive Strength and Toughness of Polyvinyl Acetate Glue on Addition of Small Quantities of Graphene

“…24 Originally produced in very small quantities, 25 graphene can now be produced in large quantities by exfoliation 26 of graphite in solvents, 27 aqueous surfactant solutions 28 or polymer solutions. 29,30 Already, graphene has displayed significant success in reinforcing 31-34 both thermoplastics [35][36][37] and elastomers, 38,39 in some cases at very low loading level. 36,40,41 With this in mind, graphene appears to be a promising additive for thermoplastic adhesives.…”

Functionalized Graphene Sheet Colloids for Enhanced Fuel/Propellant Combustion

“…25 Graphene sheets exhibit many of the same desirable qualities as CNTs, including high electrical conductivity and good mechanical properties, but should not contain significant quantities of metal particles that are used to catalyze CNT growth as the synthesis of FGS does not use metalcontaining catalysts. 23,24,26,27 FGS, as the functionalized form of the graphene sheet, differs from ideal graphene in that it contains chemical functional groups on the surface (epoxides and hydroxides) ( Figure 1) and on the edges (hydroxides and carboxylates). 23,24,28 The carbon to oxygen (C/O) ratio can range from 2 ("graphene oxide") to higher values, depending on the degree of reduction.…”