Effect of imidazolium ionic liquid type on the properties of nitrile rubber composites

Abstract

We investigated the influence of hydrophilic and hydrophobic imidazolium ionic liquids on the curing kinetic, mechanical, morphological and ionic conductivity properties of nitrile rubber composites. Two room temperature ionic liquids with a common cation—1‐ethyl‐3‐methylimidazolium thiocyanate (EMIM SCN; hydrophilic) and 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI; hydrophobic)—were used. Magnesium–aluminium layered double hydroxide (MgAl‐LDH; also known as hydrotalcite) was added to carboxylated acrylonitrile–butadiene rubber (XNBR) whereas fumed silica Aerosil 380 was used in acrylonitrile–butadiene rubber (NBR) as reinforcing fillers. NBR compounds were vulcanized with a conventional sulfur‐based crosslinking system whereas XNBR compounds were cured with MgAl‐LDH. The optimum cure time reduction and tensile properties improvement were obtained when both ionic liquids were added at 5 parts per hundred rubber (phr). The results revealed that EMIM SCN and EMIM TFSI induced an increase in the AC conductivity of nitrile rubber composites from 10−10 to 10−8 and to 10−7 S cm−1, respectively (at 15 phr ionic liquid concentration). The presence of ionic liquids in NBR slightly affected the glass transition temperature (Tg) whereas the presence of EMIM TFSI in XNBR contributed to a shift in Tg towards lower temperatures from −23 to −31 °C, at 15 phr loading, which can be attributed to the plasticizing behaviour of EMIM TFSI in the XNBR/MgAl‐LDH system. Dynamic mechanical analysis was also carried out and the related parameters, such as the mechanical loss factor and storage modulus, were determined. © 2013 Society of Chemical Industry

Developing highly conducting and mechanically durable styrene butadiene rubber composites with tailored microstructural properties by a green approach using ionic liquid modified MWCNTs

“…23,24 Curatives must dissolve in the rubber and diffuse to the active sites to react effectively for the efficient crosslinking of rubber. 25 It can be concluded that ionic liquid improved the dispersion of curing agents particularly zinc oxide in the polymer matrix, so their presence in rubber composites contributed to a considerable decrease of vulcanization time and an increase in the crosslinking efficiency.…”

Properties of Carboxylated Nitrile Rubber/Hydrotalcite Composites Containing Imidazolium Ionic Liquids

“…[12] In other investigations, the electrical conductivity of IL-CNTs/CR composites increased upon accelerated thermal aging, and therefore, the authors concluded that these composites may be useful for applications where conductivity at elevated temperatures is required. [13] The use of ILs as dispersion agents has been reported not only for CNTs in a polar polychloroprene elastomer, but also in other combinations, including: ILCNTs-OH/hydrogenated nitrile rubber (HNBR), [14] IL-carbon black/solution-styrene-butadiene rubber (SSBR), [15] ILCNTs/SSBR, [16] IL-CNTs/SSBR/butadiene rubber (BR), [17] silica/styrene-butadiene rubber (SBR), [18] silica/SBR, [19] halloysite nanotubes (HNTs)/SBR, [20] IL-HNTs/ SBR, [21] silica/nitrile rubber NBR, [22] and layered double hydroxide (LDH)/carboxylated nitrile rubber (XNBR). [22] For applications in electrochemical devices, where flexibility, thermal stability and high ionic conductivity are required, polymer electrolytes are frequently based on NBR mixed with an ionic liquid and show greatly enhanced ionic conductivity.…”

“…[13] The use of ILs as dispersion agents has been reported not only for CNTs in a polar polychloroprene elastomer, but also in other combinations, including: ILCNTs-OH/hydrogenated nitrile rubber (HNBR), [14] IL-carbon black/solution-styrene-butadiene rubber (SSBR), [15] ILCNTs/SSBR, [16] IL-CNTs/SSBR/butadiene rubber (BR), [17] silica/styrene-butadiene rubber (SBR), [18] silica/SBR, [19] halloysite nanotubes (HNTs)/SBR, [20] IL-HNTs/ SBR, [21] silica/nitrile rubber NBR, [22] and layered double hydroxide (LDH)/carboxylated nitrile rubber (XNBR). [22] For applications in electrochemical devices, where flexibility, thermal stability and high ionic conductivity are required, polymer electrolytes are frequently based on NBR mixed with an ionic liquid and show greatly enhanced ionic conductivity. [23,24,25] Homogeneous distribution of fillers and increased ionic conductivity are two major reasons for the incorporation of ionic liquids in elastomer composites.…”

Physico-mechanical and thermal properties of epoxidized natural rubber/polylactide (ENR/PLA) composites reinforced with lignocellulose

“…The term lignocellulose is used to describe the three-dimensional polymeric composites that plants create as structural materials. It is composed of variable parts of cellulose, hemicellulose and lignin [12][13][14][15][16][17][18][19][20][21][22][23][24].…”