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In the work, new type composites of acrylonitrile butadiene rubber (NBR) and polyurethane-sericite (PU-sericites) hybrid materials was prepared by melt blending method. The PU-sericite hybrid phase was formed via the reaction of NCO groups of NCO terminated PU prepolymer and OH groups of sericites. It was indicated by dynamical mechanical analysis that the damping property of NBR decreases as the amount of PU increases, whereas the mechanical properties at low temperature are enhanced. When PU of 10 wt% was added in, a better damping property can be obtained. The damping property of NBR/PU composites would decrease when adding in sericites, however, the mechanical properties at low temperature would be improved. With PU-sericites hybrid added, the compatibility between sericites and NBR/PU composites would be enhanced and the quasi-interpenetrating polymer network structures would be formed, resulting in a better mechanical property of NBR/(PU-sericites) composites. [ABSTRACT FROM AUTHOR]

The success of carbon nanotubes (CNTs) as fillers in improving the physicochemical and mechanical properties of polymer is attributed to their unique structure and performance characteristics. The interfacial interaction between fillers and matrix is of significant influence in agglomeration of fillers and mechanical/damping properties of as-prepared composites. Here, polydopamine (PDA), (3-Aminopropyl) triethoxysilane (KH550) and ionic liquid (1-aminoethyl-3methylimidazolium bis ((trifluoromethyl) sulfonyl) imide)) were used to not only functionalize CNTs for suppressing their agglomeration, but also regulate the interfacial interaction between CNTs and carboxylated butadiene nitrile rubber (XNBR) for achieving excellent mechanical properties and better damping properties. The storage modulus of composites rose by 80% (from 1392 to 2488 MPa) with the addition amount of 2.2 wt% CNTs-KH550 and the tensile strength rose by 110% (from 0.32 to 0.68 MPa) with 3.0 wt% CNTs-IL. In addition, the damping degradation of composites caused by the agglomeration of fillers was resolved. The results of molecular dynamics (MD) simulation show that the strong interfacial interaction of CNTs-PDA and CNTs-KH550 is mainly attributed to hydrogen bond interaction, while the interaction of CNTs-IL is determined by hydrogen bond interaction and van der Waals' (vdW) force. The functionalized CNTs with excellent interfacial interaction and dispersion have bright application prospects in the field of composite. Image 1 • Prepared three functionalized CNTs by grafting PDA, KH550 and ionic liquid. • Improved the dispersion of CNTs in XNBR through functionalization. • Enhanced the mechanical properties (80%) of XNBR composite and suppressed the decrease in damping properties. • Analyzed the interfacial interaction between filler and matrix by molecular dynamics simulation on the molecular scale. [ABSTRACT FROM AUTHOR]

Graphene oil as an emerging lubricant usually did not achieve the desired lubricity due to the poor interface compatibility of graphene and base oil, especially at harsh friction conditions. Herein, a simple mechanical grinding method was first carried out to fabricate trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate modified graphene gel ([P 66614 [DEHP]-G) for high-performance additive. The as-prepared [P 66614 [DEHP]-G gel shows the extraordinary thermostability, dispersity and tribological properties even at high load and temperature conditions. TOF-SIMS and Raman analysis on the friction interface reveal the existence of multi-film structure which presents good synergistic lubricating effect thereby improving the tribological behaviors. This paper provides a good strategy to fabricate high-performance oil-miscible graphene composites for reducing the friction and wear under harsh conditions. Image 1 • Trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate modified graphene gel ([P 66614 [DEHP]-G) was successfully prepared with a simple mechanical grinding method. • The [P 66614 [DEHP]-G displays good thermostability and dispersity in nonpolar hydrocarbon oil (150 N). • The [P 66614 [DEHP]-G significantly enhances the load-carrying capacity of base oil and avoids getting stuck of tribo-pairs under high load and temperature conditions. • The excellent lubricity of [P 66614 [DEHP]-G is ascribed to the formation of multi-film structure (tribo-chemical film and graphene deposition film) which displays high thermostability and synergistic lubricating effect. [ABSTRACT FROM AUTHOR]

Achieving good dispersion stability of graphene oxide (GO) nanosheets in lubricants remains a challenge due to its inherent nature. Here, the isopropyl triisostearyl titanate modified graphene oxide (T-GO) was prepared for improving its dispersion stability in hydraulic oil via a simple method, and for further enhancing the tribological behaviors. The chemical and structural features of T-GO illustrate that the titanate coupling agent (T) was successfully grafted on the plane or interlayer of GO via the interaction between T and hydroxy. The high dispersibility of T-GO in hydraulic oil was demonstrated by the sedimentation experiment and UV–vis absorption spectra (good stability and no sedimentation after 30 days). The 0.08 wt% T-GO hybrid hydraulic oil displayed excellent extreme pressure performance (load carrying capacity raises at least 400 N), friction reduction (friction cofficient reduces by nearly 50%) and wear resistance (wear volume decreases by about 20%). The surface/interface analysis on the worn surfaces testified the formation of graphene-based tribo-film on the contact interfaces. Hence, the excellent lubrication function of T-GO hybrid hydraulic oil was attributed to not only high dispersion stability of T-GO, but also the formation of graphene-like tribo-film, thereby reducing the friction and protecting the tribo-interfaces against wear. Image 1 • Achieving high dispersion stability of functional graphene oxide (T-GO) in hydraulic oil by grafting the titanate coupling agent (T). • T-GO hybrid nanofluids with excellent extreme pressure performance and friction reduction as well as wear resistance. • Excellent lubrication function of T-GO hybrid nanofluids depends good dispersibility and graphene-like tribo-film. [ABSTRACT FROM AUTHOR]