Application of ionic liquids in rubber elastomers: Perspectives and challenges

Ionic liquids are solid electrolytes having very low vapor pressure and emerging class of 'green solvents' in chemistry and material science research. They are composed of two structural units having an ionic bulky head and non-polar alkyl chain. Their properties can be tuned according to the modification of these structural units making them suitable for selected applications. They can be recycled without any impact on the environment which provides impressive advantage on environmental safety and harmless preparation chemical methods. So, these compounds stand as alternative by overcoming the limitations of conventional chemical solvents. The idea of using Ionic liquid for enhancement of characteristics of polymer nanocomposites is an unique new field which involves processing the research getting significant attention. Two major problems of conventional polymer nanocomposites such as entanglement of reinforcements (fillers) and stability of the nanocomposites can be effectively solved by the action of ionic liquid. This review addresses the progress of works which employ ionic liquid in different rubber elastomer matrices. Agglomeration of fillers is the major challenge possessed by rubber composites resulting in poor performance in their applications. Proper dispersion of fillers will give composites with enhanced properties for recently reported applications such as biomedical materials, energy storage devices, and stimuli responsive sensors and actuators. Different types of fillers used in these materials are also addressed based on their interaction with ionic liquid and the future perspectives are also shown. Finally, we propose a hypothetical model which represents the coupling activity of Ionic liquid between reinforcement and Polymer matrix which is not yet reported.

Automated summary

Ionic liquids are solid electrolytes with low vapor pressure, being considered as 'green solvents' in chemistry and material science research. They have a ionic bulky head and non-polar alkyl chain, and their properties can be modified for specific applications. By using ionic liquids, the entanglement of fillers and stability of polymer nanocomposites can be effectively solved. This review discusses the application of ionic liquids in rubber elastomer matrices, addressing the challenges of agglomeration of fillers and future perspectives.