*2.3.5 Grease*

In 2012, two types of conductive lubricating greases consisting of ILs (abbreviated as 'ILs lubricating greases') and HPPs were synthesised using 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF6]) (L-P108) and 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF4]) (LB108) as the base oil and PTFE as the thickener, exhibiting higher conductivities than the traditional conductive lubricating greases containing conductive stuffing, as shown in **Figure 11** [135]. The conductive lubricating greases using 1-hexyl-3-methylimidazolium tetrafluoro-borate ([hmim] [BF4]) and 1-hexyl-3-methylimida-zolium bis(trifluoromethylsulphonyl)amide ([hmim][Tf2N]) were prepared, and the conductivity and tribological performance of these greases were studied [136, 137]. By changing the type of ILs, different types of conductive lubricating greases were obtained [138].

In addition, the materials obtained by the blending of ILs with HPPs also include IL marbles containing PTFE and IL [139], PAI hollow fibre containing [bmim]

**113**

*Progress in Ionic Liquids as Reaction Media, Monomers and Additives in High-Performance…*

[Tf2N] [140], IL-coated PTFE tube [141], PVDF/IL functionalised graphene oxide (GO-IL) composite (PGL) films [142] and electro-active electrospun fibre containing PVDF and [bmim][Tf2N] [143]. For the materials obtained by the blending

*The photo images of the IL lubricating greases and poly-a-olefin (PAO) grease: PAO10 (abbreviate as 'PAO* 

Studies on ILs as the reaction media, monomers and additives in the synthesis, chemical modification and physical processing of HPPs are in progress. In 2017, the synthesis of poly(phenylene sulphide sulphone) (PPSS) in ILs was also presented. ILs are not only interesting as a replacement for traditional volatile and flammable organic solvents, but also have the potential to reduce energy consumption and increase chemical reactivity, thus leading to more efficient processes for the synthesis of HPPs. Using ILs in the synthesis of HPPs, promising and novel established approaches have been developed under mild conditions. Owing to their high ionic conductivity and polarisability, ILs, as excellent MW-absorbing agents, were introduced to polymerisation reactions to achieve higher yields and purer products than the traditional heating method. Notably, the number of novel copolymers of HPPs with polymerisable ILs has steadily increased in recent years, and they were mainly used in separating gases such as O2, N2, CH4 and CO2. ILs are not only used as reaction media in polymerisations for preparing HPPs and as monomers in the chemical modifications of HPPs, but also ILs are miscible with some HPPs and used as various types of additives (such as the components of polymer materials, plasticizers and porogenic agents) in the physical processing of HPPs. The materials prepared include membranes, microcapsules, electrolytes, NCs and grease. HPPs and inorganic substrates have been used to support IL materials by the covalent bonding of ILs, where the properties of ILs may be changed to some extent, and HPP membranes and NC-absorbed ILs exhibit concomitant changes in ionic conductivity and mobility. These novel green chemical approaches provide diverse possible new materials, and it is expected that more modified materials of HPPs and ILs with special properties and applications would be obtained. It is believed that more studies on ILs con-

The authors would like to acknowledge the National Science Foundation of China (grant no. 21274014), Beijing Municipal Commission of Education, the

<sup>−</sup> and Tf2N<sup>−</sup> are most often used

*DOI: http://dx.doi.org/10.5772/intechopen.86472*

*lubricating grease') (a) L-P108 (b) and LB108 (c).*

of ILs with HPPs, ILs based on imidazole and PF6

taining HPPs will be reported in the future.

**Acknowledgements**

**3. Conclusions**

**Figure 11.**

[144, 145]. PVDF, PSF and PI are the most popular [44, 146–148].

*Progress in Ionic Liquids as Reaction Media, Monomers and Additives in High-Performance… DOI: http://dx.doi.org/10.5772/intechopen.86472*

#### **Figure 11.**

*Solvents, Ionic Liquids and Solvent Effects*

(GIL) composites [132, 133]. NCs, based on a homopolymer PVDF and IL, were fabricated, and the preparation process opens up a new synthesis route for nanostructured polymer composites. Dielectric NCs based on PVDF, conductive carbon black (CB) and IL 1-vinyl-3-ethylimidazolium tetrafluoroborate [VEIM][BF4] were prepared via melt blending and electron beam irradiation (EBI) methods [134]. A nanostructured PAI was prepared in TBAB as a green medium by the step polymerisation reaction of 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) with 3,5-diamino-*N*-(4-hydroxy-phenyl)benzamide. Then, amino acid-functionalised multiwalled carbon nanotubes (f-MWCNTs)/PAI NCs were

*Processing of PEI/bucky gel nanocomposites; the obtained composites had good toughness as the film could be* 

In 2012, two types of conductive lubricating greases consisting of ILs (abbreviated as 'ILs lubricating greases') and HPPs were synthesised using 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF6]) (L-P108) and 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF4]) (LB108) as the base oil and PTFE as the thickener, exhibiting higher conductivities than the traditional conductive lubricating greases containing conductive stuffing, as shown in **Figure 11** [135]. The conductive lubricating greases using 1-hexyl-3-methylimidazolium tetrafluoro-borate ([hmim] [BF4]) and 1-hexyl-3-methylimida-zolium bis(trifluoromethylsulphonyl)amide ([hmim][Tf2N]) were prepared, and the conductivity and tribological performance of these greases were studied [136, 137]. By changing the type of ILs, different types

In addition, the materials obtained by the blending of ILs with HPPs also include

IL marbles containing PTFE and IL [139], PAI hollow fibre containing [bmim]

prepared by a solution mixing method [30].

of conductive lubricating greases were obtained [138].

**112**

*2.3.5 Grease*

**Figure 10.**

*curved adequately without any damage.*

*The photo images of the IL lubricating greases and poly-a-olefin (PAO) grease: PAO10 (abbreviate as 'PAO lubricating grease') (a) L-P108 (b) and LB108 (c).*

[Tf2N] [140], IL-coated PTFE tube [141], PVDF/IL functionalised graphene oxide (GO-IL) composite (PGL) films [142] and electro-active electrospun fibre containing PVDF and [bmim][Tf2N] [143]. For the materials obtained by the blending of ILs with HPPs, ILs based on imidazole and PF6 <sup>−</sup> and Tf2N<sup>−</sup> are most often used [144, 145]. PVDF, PSF and PI are the most popular [44, 146–148].
