Synthesis of new ionic liquid-grafted metal-oxo nanoclusters – Design of nanostructured hybrid organic-inorganic polymer networks

Abstract

Designing innovative multi-functional thermoset polymers represents a major challenge in materials science. In this work, two novel polyhedral imidazolium ionic liquid supported on oligomeric silsesquioxane nanocages having chloride (Cl − ) and bistrifluoromethanesulfonimidate (NTf 2 -) counter anions have been synthesized. These ionic nano-objects were used to nanostructure a model epoxy network. Hence, networks displaying a homogeneous nanoscale morphology were obtained by introducing 5 wt % of such organic-inorganic (O/I) silicon-oxo clusters functionalized with ionic liquids. The obtained ionic hybrid O/I epoxy-amine networks display an excellent thermal stability (>400 • C) compared to their neat counterparts, as well as a pronounced hydrophobic character (23 mJ m − 2 ) and good mechanical performances. Moreover, these O/I nanostructured networks demonstrate an improved fire resistance according to pyrolysis-combustion flow calorimetry (PCFC) and cone calorimetry analyses. In fact, the use of low amounts of imidazolium ionic liquid-modified polyhedral oligomeric silsesquioxanes induce a significant decrease of heat release rate (about 55%), as well as a retardation of the ignition time (close to 29%) compared to the neat epoxy-amine network.

New Epoxy Thermosets Organic-Inorganic Hybrid Nanomaterials Derived from Imidazolium Ionic Liquid Monomers and POSS®Ph

“…The interconnected nanophase-separated morphology with uniform domain size is characteristic of self-assembled structures generated as result of a balance of different intermolecular and intercluster interactions [ 52 , 53 ]. It should be pointed out that the dispersion of POSS ®Ph -triol clusters in the ILM1 or ILM2-based matrix is better than the one obtained with DGEBA/IPD network, where the diameter distribution is ranging from 0.1 to 1.5 µm [ 45 ]. For epoxy ILM/IPD networks containing IL-g-POSS ®Ph with chloride (Cl − ) or bistrifluoromethanesulfonimidate (NTf 2 − ) counter anions, the TEM micrographs show that the phase separation occurred at nanoscale.…”

“…In addition, the reaction kinetics, i.e., the quantification of the epoxide groups conversion, for all the reactive systems were investigated by FT-IR spectroscopy following the curing conditions: 3 h at 80 °C, 6 h at 120 °C, and 1 h at 200 °C for ILM1/IPD and 1 h at 140 °C followed by 8 h at 190 °C for ILM2/IPD. All the reactive systems were analyzed in the wavelength region of 800–1300 cm −1 in order to follow the changes of the adsorption bands at 914 and 1132 cm −1 corresponding to the epoxy groups with reference as the absorption band at 1132 cm −1 (trifluoromethyl (-CF 3 ) of bis(trifluoromethanesulfonyl)imidate counterions (NTf 2 − ) [ 46 ], respectively, by using the following equation [ 28 , 45 , 46 ]: where A 0 and A t are the ratios between the area of two absorption bands at 914 and 1132 cm −1 ( A 914 / A 1132 ) of the reactive system at the beginning of the reaction ( t = 0) and at a given reaction time t. Thus, the epoxy conversion versus the polymerization time is presented in Figure S2a and S2b .…”

“…The grafting of ionic liquids onto POSS ® [ 41 , 42 ] has shown a strong improvement of ionic conductivity, excellent electrochemical stability, and high thermal stability compared to systems which only contain POSS ® [ 38 , 39 , 40 ] or POSS ® with free ionic liquid [ 43 ]. Our previous studies reported also that the connection of ion pairs to POSS ®Ph with different organic ligands (isobutyl or phenyl) can significantly help to improve the O/I interphase and promote the formation of well-dispersed POSS ® nanodomains [ 44 ] leading to nanomaterials with outstanding thermal and mechanical properties [ 45 ]. From these previous results and the ones reported in the literature, it is plausible that a new generation of electrolyte could be designed.…”

Microencapsulated Diepoxy-Functionalized Ionic Liquids to the Design of Self-Healable Epoxy Networks

“…Due to their advantageous mechanical performances, i.e., stiffness, high specific strength, combined with the increasing demand from industries for advanced lightweight materials, filler-reinforced polymer composites are widely used for applications including vehicles, wind turbine blades, and aircraft structures. − Most often, low-cost materials, including thermoset matrices based on epoxy networks with a highly cross-linked nature, corrosion and chemical resistances, high thermal stability, and good mechanical performances, are of great interest . However, these polymer composites are more prone to microcracking when subjected to cyclic thermal or mechanical loads and impacts .…”

A Mesoporous Magnetic Fe3O4/BioMOF-13 with a Core/Shell Nanostructure for Targeted Delivery of Doxorubicin to Breast Cancer Cells

“…Various strategies of composition can lead to distinct architectures in hybrid materials, causing them to exhibit different properties. For instance, organic–inorganic hybridization has been reported, where a polymeric network has been combined with an inorganic component, such as metal oxide nanoparticles, resulting in a unique architecture. , …”