In Situ Interfacial Polymerization: A Technique for Rapid Formation of Highly Loaded Carbon Nanotube‐Polymer Composites

Abstract

Composites of polymers and organized carbon nanotube (CNT) networks have been proposed as next-generation lightweight structural materials, yet polymer infiltration of CNT networks often results in stress-concentrating heterogeneities, due to local CNT aggregation or incomplete infiltration. Herein, it is demonstrated that dense CNT-polymer composites with tailored polymer distribution can be obtained by interfacial polymerization (IP), performed in situ within CNT networks. Three regimes of the in situ interfacial polymerization (ISIP) process are identified: a reaction-limited regime where the polymer forms beads on the CNTs; a uniformly-filled regime with polymer throughout the CNT network; and a transport-limited regime with polymer only near the outer surface of the network. Uniform polyamide-CNT composite sheets obtained by this method have a Young's modulus of 31 GPa and a tensile strength of 776 MPa, which is a twofold increase compared to the pristine CNT sheets. Premature failure of the composites is attributed to large voids in the pristine CNT sheets, suggesting that further improved mechanical properties can be achieved with a more homogeneous CNT network. Nevertheless, the rapid rate and overall controllability of ISIP suggest its viability for formation of polymers within CNT networks via roll-to-roll methods.

Molecular Alignment of a Meta-Aramid on Carbon Nanotubes by In-Situ Interfacial Polymerization.

“…20 In recent work, we showed that PMPI forms in droplets or conformal sheaths around the CNTs, depending on the relative rates of transport and reaction kinetics. 20 The polymer formed is amorphous in nature, demonstrating that commonly observed crystallization of meta-aramids through interchain hydrogen interaction 21 does not contribute to ordering of PMPI in the vicinity of CNTs. Instead, we expect from literature that the prominent π-interaction 22 involving PMPI meta-phenyl rings and the outer wall of CNTs induces short-range molecular ordering of polymer chains onto the CNT.…”

“…Here we show that conformal polymer coatings on CNTs can be obtained by in-situ interfacial polymerization (ISIP) of meta-aramids, 19,20 through short-range molecular ordering of the polymer chains and long-range nucleation and growth of polymer particles. ISIP of metaaramid poly(m-phenylene isophthalamide) (PMPI) relies on the reaction of m-phenylene diamine (MPD) dissolved in water with isophthaloyl chloride (IPC) dissolved in an organic solvent (in this case, cyclohexanone) (Figure 1).…”

Construction of carbon-based flame retardant composite with reinforced and toughened property and its application in polylactic acid

“…In recent decades, with the vigorous development of carbon nanomaterials, carbon nanotubes (CNTs) have been widely used as reinforcement and toughening materials for polymers. 17 For instance, Liu et al 18 added block copolymer-modified multi-walled carbon nanotubes (bc@fMWNTs) to epoxy resin (EP) to prepare nanocomposites and showed that only 0.05 wt% bc@fMWNTs could achieve 15% increase in tensile strength of EP. Moreover, numerous studies have shown that CNTs can be used as flame retardant additives for polymers, and adding a very small amount of CNTs can effectively reduce the heat release rate of the polymers.…”

Molecular Alignment of a Meta-Aramid on Carbon Nanotubes by In Situ Interfacial Polymerization

“…Here, we show that conformal polymer coatings on CNTs can be obtained by in situ interfacial polymerization (ISIP) of meta-aramids, , through short-range molecular ordering of the polymer chains and long-range nucleation and growth of polymer particles. ISIP of meta-aramid poly­(m-phenylene isophthalamide) (PMPI) relies on the reaction of m-phenylenediamine (MPD) dissolved in water with isophthaloyl chloride (IPC) dissolved in an organic solvent (in this case, cyclohexanone) (Figure ).…”

“…Last, rinsing and solvent evaporation result in a CNT–PMPI composite free of impurities and unreacted monomers (Figure d). By adjusting monomer concentration, the mass of the polymer produced as well as the morphology of the polymer coating onto the CNTs can be adjusted …”