Rheological and Mechanical Properties of Silica/Nitrile Butadiene Rubber Vulcanizates with Eco-Friendly Ionic Liquid

Abstract

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

Viscoelastic Rheological Behaviors of Polypropylene and LMPP Blends

“…Figure 5a shows the elastic Lissajous curves of the σ against γ0; at lower γ0 the blends kept constant shape, with no response with the addition of LMPP. Whereas at higher γ0 the blends kept the elliptical The complex viscosity (*η) of the pure iPP and LMPP blends is shown in Figure 4d; the data are fitted with the Carreau-Yasuda model [33], suggesting pure iPP, and all blends demonstrated shear-thinning behavior. Addition of lower M w polymer LMPP lowers the *η of the blends compared to pure iPP, which may be ascribed to the better polymeric adhesion between them.…”

“…The complex viscosity (*η) of the pure iPP and LMPP blends is shown in Figure 4d; the data are fitted with the Carreau-Yasuda model [33], suggesting pure iPP, and all blends demonstrated shear-thinning behavior. Addition of lower Mw polymer LMPP lowers the *η of the blends compared to pure iPP, which may be ascribed to the better polymeric adhesion between them.…”

Dispersion and vulcanization characteristics of nitrile rubber reinforced with N,N‐dimethylacetamide/lithium chloride treated silica

“…DMAc/LiCl treatment of silica has resulted in a reduction in viscosity of these compounds while accelerating the vulcanization to a higher state in samples containing TESPT along with DMAc/LiCl as evident from the vulcanization curves. The combination of DMAc/LiCl with TESPT has shown to be effective in reducing initial viscosity as evident from the minimum torque values combined with enhanced states of vulcanization as indicated by higher final torque values 39 . Significantly, the rheographs do not indicate changes in the ts2 values within a particular grade of nitrile rubber.…”

“…The combination of DMAc/LiCl with TESPT has shown to be effective in reducing initial viscosity as evident from the minimum torque values combined with enhanced states of vulcanization as indicated by higher final torque values. 39 Significantly, the rheographs do not indicate changes in the ts2 values within a particular grade of nitrile rubber. Lower initial torque values of these compounds with enhanced state of cure in the final vulcanizates could be attributed to reduced self-association among silica particles, aggregates, and agglomerates as a result of DMAc/LiCl treatment and better inter-association of silica with the rubber matrix.…”

Multi-Stressed Nano and Micro-Silica/Silicone Rubber Composites with Improved Dielectric and High-Voltage Insulation Properties

“…Silica is incoporated in silicon rubber as agglomerates; particularly, the migration of fillers plays an important role in vulcanized rubber: it detoriates the various properties of composites during their use Figure 1 . To attain stability in desired properties of composites, the interfacial interactions between filler and rubber should be madiated crucially [ 54 ].…”