Simultaneous Improvement on Strength, Modulus, and Elongation of Carbon Nanotube Films Functionalized by Hyperbranched Polymers

Abstract

Carbon nanotube (CNT) buckypapers, or films, have the potential for wide applications because of their unique properties. Neat buckypapers or pristine CNT (PCNT) films have relatively large elongation but low strength and low modulus due to the weak interaction between CNTs. Chemical modifications of PCNT films can significantly strengthen the interaction between CNTs, resulting in high strength and high modulus but usually accompanied by low elongation. Here, we report the functionalization of pristine CNT films by thiol-ended hyperbranched polymers (THBP-n) via a thiol-ene click reaction that can introduce simultaneous improvements on the strength, modulus, and elongation to the PCNT film by 689, 812, and 32.4%, respectively. The high thiol content of THBP-n enables the formation of a network with a high degree of cross-linking between carbon nanotubes, which provides high-efficiency load transfer that increases the tensile strength and modulus of the resulting films and at the same time a compressible hyperbranched structure that allows for deformation and slip between CNTs and consequently improved elongation. The main factors affecting the mechanical performance of the functionalized CNT film are also investigated.

Tuning the piezoresistive strain‐sensing behavior of poly(vinylidene fluoride)–CNT composites: The role of polymer–CNT interface and composite processing technique

“…Simultaneous strengthening and toughening in CNT composites has been found for a few polymer nanocomposites. 68 The flexibility of a typical composite film is demonstrated in Figure S6.…”

Highly advanced phthalonitrile composites from epoxy‐ended hyperbranched poly(trimellitic anhydride ethylene glycol) ester grafted basalt fibers

“…Furthermore, such polymers show outstanding penetrability and solubility, and display a lower viscosity and melting point compared with linear polymers of the same molecular weight. [23][24][25][26][27] To our best knowledge, the impact of surface modification with the hyperbranched polymers on the mechanical, morphological, and impact properties of chopped BFs (CBFs) reinforced PN composites has never been studied before. In addition, the proposed treatment method is also cost-effective and enables the grafting of a consequent number of reactive terminal groups on the outer surfaces of the BFs for an effective compatibility with the PN matrix.…”

Interfacial characteristics of a carbon nanotube-polyimide nanocomposite by molecular dynamics simulation

“…Carbon nanotubes (CNTs), due to their high aspect ratios, have been regarded as one of the most promising reinforcement material in polymer-based nanocomposites [1][2][3][4][5][6]. Using pullout experiments with atomic force microscopy, the interfacial shear strength of CNTs within polymer matrices have been measured in the range of 35 to 380 MPa [7,8].…”