Simultaneous enhancement of electrical conductivity and interlaminar shear strength of CF/EP composites through MWCNTs doped thermoplastic polyurethane film interleaves

Abstract

Carbon fiber‐reinforced epoxy (CF/EP) composites have been widely used in aerospace industry, while poor electrical conductivity and interlaminar shear fracture toughness could reduce their safety as structural components in use. In this work, we achieved simultaneous improvement in electrical conductivity and interlaminar shear strength through interleaved multi‐walled carbon nanotubes (MWCNTs) doped thermoplastic polyurethane (TPU) conductive thin films (CTFs), which were prepared by a solution casting method. The experimental results showed that the electrical conductivity of the laminates increased by about 13 and 16 times in the transverse and thickness directions with only about 1 wt % MWCNTs content in the laminates. The end‐notch flexure (ENF) tests showed that the mode II interlaminar fracture toughness (GIIC) of composites with 10 wt % MWCNTs CTF interleaf shows a significant increase of about 106%. The enhancement mechanism was further explored through microscopic morphological observation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47988.

Improved Interlaminar Fracture Toughness and Electrical Conductivity of CFRPs with Non-Woven Carbon Tissue Interleaves Composed of Fibers with Different Lengths

“…Compared with the baseline CFRPs laminates, after the incorporation of NWCTs with density of 7.8 mg/cm 2 , the in-plane electrical conductivity was increased by over 96% (Figure 7a), while the through-the-thickness electrical conductivity was increased by over 82% (Figure 7b). which are higher than that of CRRP interleaved by other carbon interleave materials such as black@PPNWF [18] and CNTs-doped polyamide [9] in the literature, as shown in Table 3, indicating excellent electrical conductivity of the NWCT with commercial short carbon fiber as for the conductive interleave in CFRPs laminate. Obviously, the increase in electrical conductivity is due to the connected conductive network of SCFs with high density (7.8 mg/cm 2 ) in the matrix between fabrics plies, evidenced by Figure 4a.…”

“…Among these methods, the interleaving technique is one of the latest developed technologies, which keeps the simplicity in the manufacturing process. Current representative interleave methods can be classified into several strategies: (1) chemical synthetic interleaf film on fabric surface [8], (2) nanoparticles/thermoplastic or thermosetting film [9], (3) electrospinning nanofiber film [10], (4) nanoparticles film [11], (5) commercial non-woven tissue (NWT) [7], which all give the greatest contribution to interlaminar toughness improvement of the composite laminate. However, the first four methods still have some problems such as high dependence on some specialized equipment, low preparation efficiency and high cost, which are not applicable and realistic to practical application, instead, the commercial polymer interleaf materials have the advantages of mature production process, high production efficiency and low cost.…”

Methods of modifying through-thickness electrical conductivity of CFRP for use in structural health monitoring, and its effect on mechanical properties – A review

“…Though an increase in malleability may also mean that the veil does not hold its structure and is therefore compacted reducing the space for infusion. Li et al [9,75] used polyamide 12 (PA12) and multiwalled carbon nanotubes (MWCNT) to produce an interleave with strong interfacial bonding as well as good conductivity. The baseline composite consisted of high temperature UD CF/Epoxy prepreg (BONATECH Advanced Materials company).…”

Multifunctional nickel‐coated carbon fiber veil for improving both fracture toughness and electrical performance of carbon fiber/epoxy composite laminates

“…[28] Therefore, functionalized interlayer technology [29] has been explored, and the development of structurally electrically conductive CFRPs has become an attractive research area. Some researchers have successfully coated or deposited carbon nanofillers, such as CNTs, [30,31] carbon black, [28] and graphene, [32] or metal nanoparticles [33,34] on interleaving materials to improve their electrical conductivity. However, the poor dispersibility, high cost, and complex manufacturing process may limit their wide application in practical engineering.…”