Janus Nanosheets Synchronously Strengthen and Toughen Polymer Blends

Abstract

Strength is usually compromised with toughness of polymer blends. We report a new way to synchronously strengthen and toughen a typical blend of epoxy resin/nitrile-butadiene rubber (EP/LNBR) with Janus nanosheets (JNs). The silica-based JNs contain a reactive epoxide group and nitrile-butadiene rubber on the opposite sides. They are robust of high strength and toughness. The JNs are covalently bound at the EP/LNBR interface upon blending and cross-linking, which can effectively transfer stress in between the two phases. At the saturation coverage of the interface with the JNs, mechanical properties of the blends reach the maxima. Excess JNs will stack into multiple layers at the interface, which will lead to interfacial slippage and thus to worse properties. This report may open a new avenue to achieve higher performance polymer materials by using Janus materials.

Stabilizing Polymeric Interface by Janus Nanosheet

“…[ 21 ] Besides spherical contour, highly asymmetric Janus nanosheets have gained growing concerns as compatibilizers. [ 28–32 ] When using the polystyrene‐silica‐polyisoprene JNS as the compatibilizer in the PS/PI solution blend, the domains become smaller which is less dependent on annealing at high temperature. [ 31 ] In contrast, the domains become coarsening after the annealing.…”

“…In our recent report, a small amount of EP/NBR JNS (EP: epoxide group, NBR: nitrile‐butadiene rubber) can synchronously strengthen and toughen the epoxy resin/nitrile‐butadiene rubber (EP/LNBR) blend. [ 32 ] However, interfacial behavior of the JNS remain unclear. Recently, Russell and co‐workers have proposed the pioneering idea that a Janus nanoparticle can form some jamming structure at the liquid/liquid interface, providing a new strategy to stabilize interfaces.…”

Research Advances in the Synthesis, Application, Assembly, and Calculation of Janus Materials

“…As shown in Figure , most Janus nanosheets are prepared by using a template method or crushing hollow microspheres. Then, modification occurs. ,− 2D graphene oxide nanosheets and silica nanosheets are often used as substrates for the development of Janus nanosheets with multifunctional properties. − This section briefly introduces the latest research progress of Janus nanosheets in emulsion stabilization and increased oil recovery, blending, and cross-linking to improve the stability of polymer mixtures, as a molecular imprinting platform for sewage treatment, and as a nanocatalytic enzyme.…”

“…During blending and cross-linking, the Janus nanosheet covalently bonded at the epoxy resin/nitrile–butadiene rubber interface, effectively transferring stress between the two phases. As a typical mixture of epoxy/nitrile rubber for simultaneous reinforcement and toughening effect, Ma designed Janus GO-poly­(2-(acryloyloxy)­ethyl ferrocenecarboxylate)/polydopamine (GO-PMAEF/PDA) nanomaterials. They achieved the dual self-healing ability of the nanocomposite hydrogel via using the chemical bonding ability between the functional groups on both sides of the Janus nanosheet and the hydrogel …”

Hybridization effect of functionalized microcrystalline cellulose and liquid acrylonitrile butadiene rubber on epoxy

“…The -OH groups might bond with the surface of the rigid filler and -NH 2 with epoxy, strengthening the interface between them. 18 Hou et al 19 functionalized silica with APTES for an epoxy/CTBN system, Poonpipat et al 20 modified a commercial nanosilica with organosilane, aiming to modify the epoxy/CTBN characteristics. Chonkaew et al 21 used a commercial nanoclay, surface modified by APTES, also in an epoxy/CTBN system and justified the further improvement in properties based on better filler dispersion and adhesion to the resin conferred by functionalization.…”