Ionic Liquids as Alternative Curing Agents for Conductive Epoxy/CNT Nanocomposites with Improved Adhesive Properties

Good dispersion of carbon nanotubes (CNTs) together with effective curing were obtained in epoxy/CNT nanocomposites (NCs) using three different ionic liquids (ILs). Compared to conventional amine-cured epoxy systems, lower electrical percolation thresholds were obtained in some of the IL-based epoxy systems. For example, the percolation threshold of the trihexyltetradecylphosphonium dicyanamide (IL-P-DCA)-based system was 0.001 wt.%. The addition of CNTs was not found to have any significant effect on the thermal or low-strain mechanical properties of the nanocomposites, but it did improve their adhesive properties considerably compared to the unfilled systems. This study demonstrates that ILs can be used to successfully replace traditional amine-based curing agents for the production of electrically conductive epoxy/CNT NCs and adhesives, as a similar or better balance of properties was achieved. This represents a step towards greater sustainability given that the vapor pressure of ILs is low, and the amount needed to effectively cure epoxy resins is significantly lower than any of their counterparts.

[1]  G. Guerrica-Echevarría,et al.  Ionic Liquid-Cured Epoxy/PCL Blends with Improved Toughness and Adhesive Properties , 2022, Polymers.

[2]  M. Moniruzzaman,et al.  Ionic liquid assisted polyetheretherketone‐multiwalled carbon nanotubes nanocomposites: An environmentally friendly approach , 2021 .

[3]  Xianhai Hu,et al.  Improved mechanical and dielectric properties of PLA/EMA-GMA nanocomposites based on ionic liquids and MWCNTs , 2020 .

[4]  B. G. Soares,et al.  Phosphonium-based ionic liquid as crosslinker/dispersing agent for epoxy/carbon nanotube nanocomposites: electrical and dynamic mechanical properties , 2020, Journal of Materials Science.

[5]  A. Singh,et al.  Graphene and carbon nanotube reinforced epoxy nanocomposites: A review , 2019, Polymer.

[6]  Xingping Zhou,et al.  Noncovalent engineering of carbon nanotube surface by imidazolium ionic liquids: A promising strategy for enhancing thermal conductivity of epoxy composites , 2019, Composites Part A: Applied Science and Manufacturing.

[7]  M. Shukla,et al.  Effect of Carbon Nanofillers on the Mechanical and Interfacial Properties of Epoxy Based Nanocomposites: A Review , 2019, Polymer Science, Series A.

[8]  G. Barra,et al.  Conductive heterogeneous blend composites of PP/PA12 filled with ionic liquids treated-CNT , 2019, Polymer Testing.

[9]  B. G. Soares,et al.  Epoxy-MWCNT composites prepared from master batch and powder dilution: Effect of ionic liquid on dispersion and multifunctional properties , 2018 .

[10]  I. Hamerton,et al.  Examining the nature of network formation during epoxy polymerisation initiated with ionic liquids , 2018 .

[11]  B. G. Soares.  Ionic liquid: A smart approach for developing conducting polymer composites , 2018, Journal of Molecular Liquids.

[12]  R. Verdejo,et al.  Epoxy Nanocomposites Filled with Carbon Nanoparticles. , 2018, Chemical record.

[13]  G. Barra,et al.  Conducting melt blending of polystyrene and EVA copolymer with carbon nanotube assisted by phosphonium-based ionic liquid , 2018 .

[14]  P. K. Ghosh,et al.  MWCNTs toward superior strength of epoxy adhesive joint on mild steel adherent , 2018, Composites Part B: Engineering.

[15]  Y. Xing,et al.  DGEBA/imidazolium ionic liquid systems: the influence of anions on the reactivity and properties of epoxy systems , 2018 .

[16]  I. Hamerton,et al.  Investigating the mechanism through which ionic liquids initiate the polymerisation of epoxy resins , 2018 .

[17]  B. G. Soares,et al.  New all solid‐state polymer electrolyte based on epoxy resin and ionic liquid for high temperature applications , 2018 .

[18]  B. G. Soares,et al.  Bronsted acidic ionic liquids: New transesterification agents for the compatibilization of polylactide/ethylene-co-vinyl acetate blends , 2017 .

[19]  T. Espinosa,et al.  Synergy between graphene and ionic liquid lubricant additives , 2017 .

[20]  Bankim Chandra Ray,et al.  Mechanical, thermomechanical, and creep performance of CNT embedded epoxy at elevated temperatures: An emphasis on the role of carboxyl functionalization , 2017 .

[21]  B. G. Soares,et al.  Dual functions of ILs in the core-shell particle reinforced epoxy networks: Curing agent vs dispersion aids , 2017 .

[22]  G. Barra,et al.  Phosphonium–based ionic liquid as dispersing agent for MWCNT in melt-mixing polystyrene blends: Rheology, electrical properties and EMI shielding effectiveness , 2017 .

[23]  P. Pötschke,et al.  An Ionic Liquid as Interface Linker for Tuning Piezoresistive Sensitivity and Toughness in Poly(vinylidene fluoride)/Carbon Nanotube Composites. , 2017, ACS applied materials & interfaces.

[24]  M. Bermúdez,et al.  Synergy between single-walled carbon nanotubes and ionic liquid in epoxy resin nanocomposites , 2016 .

[25]  G. Barra,et al.  Dual-role of phosphonium – Based ionic liquid in epoxy/MWCNT systems: Electric, rheological behavior and electromagnetic interference shielding effectiveness , 2016 .

[26]  B. G. Soares,et al.  Conducting epoxy networks modified with non-covalently functionalized multi-walled carbon nanotube with imidazolium-based ionic liquid , 2016 .

[27]  C. Vagner,et al.  Functionalized-Carbon Nanotubes with Physisorbed Ionic Liquid as Filler for Epoxy Nanocomposites , 2016 .

[28]  Bo-ming Zhang,et al.  Co-continuous structural electrolytes based on ionic liquid, epoxy resin and organoclay: Effects of organoclay content , 2016 .

[29]  S. Livi,et al.  The properties of new epoxy networks swollen with ionic liquids , 2016 .

[30]  S. R. Bakshi,et al.  Effect of different carbon nano-fillers on rheological properties and lap shear strength of epoxy adhesive joints , 2016 .

[31]  M. Maghrebi,et al.  The effect of choline-based ionic liquid on CNTs' arrangement in epoxy resin matrix , 2016 .

[32]  C. Xiaoting,et al.  Thermal properties and non-isothermal curing kinetics of carbon nanotubes/ionic liquid/epoxy resin systems , 2015 .

[33]  I. Ahmad,et al.  Thermal and Mechanical Properties of Carbon Nanotube/Epoxy Nanocomposites Reinforced with Pristine and Functionalized Multiwalled Carbon Nanotubes , 2015 .

[34]  J. Gérard,et al.  Phosphonium ionic liquids as new compatibilizing agents of biopolymer blends composed of poly(butylene-adipate-co-terephtalate)/poly(lactic acid) (PBAT/PLA) , 2015 .

[35]  G. Palmese,et al.  Processing-structure–property relationships of SWNT–epoxy composites prepared using ionic liquids , 2015 .

[36]  N. Barkoula,et al.  Nano-enhanced composite materials under thermal shock and environmental degradation: A durability study , 2015 .

[37]  G. Palmese,et al.  Ultralow percolation threshold of single walled carbon nanotube-epoxy composites synthesized via an ionic liquid dispersant/initiator , 2014 .

[38]  T. Spychaj,et al.  Epoxy resin/phosphonium ionic liquid/carbon nanofiller systems: Chemorheology and properties , 2014 .

[39]  G. Palmese,et al.  Room temperature ionic liquids for epoxy nanocomposite synthesis: Direct dispersion and cure , 2013 .

[40]  B. Fox,et al.  Individual dispersion of carbon nanotubes in epoxy via a novel dispersion-curing approach using ionic liquids. , 2013, Physical chemistry chemical physics : PCCP.

[41]  J. Gérard,et al.  New epoxy systems based on ionic liquid , 2013 .

[42]  G. Lai,et al.  Fracture toughness and electrical conductivity of epoxy composites filled with carbon nanotubes and spherical particles , 2013 .

[43]  Yu-Ming Chang,et al.  Ductile polylactic acid prepared with ionic liquids , 2013 .

[44]  N. Barkoula,et al.  Effect of dispersion conditions on the thermo-mechanical and toughness properties of multi walled carbon nanotubes-reinforced epoxy , 2012 .

[45]  Liping Zhao,et al.  Impact of ionic liquid-modified multiwalled carbon nanotubes on the crystallization behavior of poly(vinylidene fluoride). , 2012, The journal of physical chemistry. B.

[46]  D. Lourdin,et al.  Compatibilization of starch-zein melt processed blends by an ionic liquid used as plasticizer. , 2012, Carbohydrate polymers.

[47]  Liping Zhao,et al.  Multifunctional role of an ionic liquid in melt-blended poly(methyl methacrylate)/ multi-walled carbon nanotube nanocomposites , 2012, Nanotechnology.

[48]  N. Markaide,et al.  Curing of epoxy/carbon nanotubes physical networks , 2012 .

[49]  V. Srivastava.  Effect of carbon nanotubes on the strength of adhesive lap joints of C/C and C/C–SiC ceramic fibre composites , 2011 .

[50]  Tom Welton,et al.  Room-temperature ionic liquids: solvents for synthesis and catalysis. 2. , 1999, Chemical reviews.

[51]  C. Espejo,et al.  Single-walled carbon nanotubes modified by ionic liquid as antiwear additives of thermoplastics , 2010 .

[52]  J. Wishart,et al.  Energy applications of ionic liquids , 2009 .

[53]  S. Amico,et al.  Effect of sonication on thermo-mechanical properties of epoxy nanocomposites with carboxylated-SWNT , 2009 .

[54]  Jinyong Wang,et al.  Why single-walled carbon nanotubes can be dispersed in imidazolium-based ionic liquids. , 2008, ACS nano.

[55]  D. Dean,et al.  Cure behavior of epoxy/MWCNT nanocomposites: The effect of nanotube surface modification , 2008 .

[56]  P. Ma,et al.  Correlations between Percolation Threshold, Dispersion State, and Aspect Ratio of Carbon Nanotubes , 2007 .

[57]  T. Chou,et al.  Carbon Nanotube Networks: Sensing of Distributed Strain and Damage for Life Prediction and Self Healing , 2006 .

[58]  H. Choi,et al.  Preparation and nanoscopic internal structure of single-walled carbon nanotube-ionic liquid gel , 2005 .

[59]  Chuck Zhang,et al.  Investigation of the dispersion process of SWNTs/SC-15 epoxy resin nanocomposites , 2004 .

[60]  F. Carmona,et al.  Role of interfacial effects in carbon nanotube/epoxy nanocomposite behavior. , 2004, Journal of nanoscience and nanotechnology.

[61]  Mustafizur Rahman,et al.  Application of ionic liquids as low-volatility plasticizers for PMMA , 2003 .

[62]  I. Kinloch,et al.  Ultra-low electrical percolation threshold in carbon-nanotube-epoxy composites , 2003 .

[63]  Takuzo Aida,et al.  Molecular Ordering of Organic Molten Salts Triggered by Single-Walled Carbon Nanotubes , 2003, Science.

[64]  Mahn-Joo Kim,et al.  Ionic liquid-coated enzyme for biocatalysis in organic solvent. , 2002, The Journal of organic chemistry.

[65]  Milo S. P. Shaffer,et al.  Development of a dispersion process for carbon nanotubes in an epoxy matrix and the resulting electrical properties , 1999 .

[66]  T. Welton.  Room-Temperature Ionic Liquids. Solvents for Synthesis and Catalysis. , 1999, Chemical reviews.