Effect of in situ fibrillation on polyethylene/poly(ethylene terephthalate)/multiwalled carbon nanotube electromagnetic shielding foams

Abstract

In this study, polyethylene (PP)/polyethylene terephthalate (PET)/multiwalled carbon nanotube (MWCNT) nanocomposites with nanofibrillary structure were processed by hot drawing‐assisted extrusion technology, and nonfoaming and microfoaming samples were processed by injection molding machine. Scanning electron microscope micrographs showed that when PET content was 2.5 wt%, PET fibers had a larger aspect ratio, which brought an outstanding promotion on microfoaming of PP matrix, and further details were provided by DSC and rheology analysis. When foaming sample loaded with 2.5 wt% PET and 3 wt% MWCNT, the best shielding effectiveness achieved 29.91 dB·cm3·g−1 in the test frequency range about 8.2–12.4 GHz. The results proved that the introduction of PET fibers optimized the microfoaming effect, and the uniform cell structure promoted the MWCNT dispersion and internal reflection of electromagnetic wave. Therefore, the shielding property is absorption‐dominated type and meets the requirements of lightweight and ultraefficient shielding demand of industry.

Preparation of lightweight and high‐strength polypropylene‐based ternary conductive polymer foams by in situ microfiber reinforcement

“…The melt heat absorption peaks of the PP/MWCNTs binary composite and the PP/MWCNTs/PTFE multicomposite also moved to higher temperatures after the second melt heat absorption process, which may be related to some crystal structures becoming more perfect. 16,18 Table 4 summarizes the key parameters of nonisothermal thermal crystallinity of the component materials. It was found that for the PC1 and PC2 groups, the crystallinity decreased with the addition of MWCNTs over pure PP.…”

“…14,15 Most previous studies have focused on in situ fibrillation-based method for obtaining fibrils with high aspect ratios, which is increasingly recognized as an effective method to improve melt strength, rheology properties, and foaming behavior. [16][17][18][19] Furthermore, the presence of fibrillar networks is related to the role of heterogeneous nucleation agents in refining crystals. Jiang et al 20 introduced polytetrafluoroethylene (PTFE) fibrils into the prepared microporous polyethylene terephthalate (PET), which improved the crystallization temperature, crystallization rate, as well as the viscoelastic behavior of PET.…”

Facile preparation and properties of polybenzoxazine/graphene porous nanocomposites for electromagnetic wave absorption

“…[12] Carbon-based wave absorbers include carbon black, graphene, graphene oxide (GO), carbon fibers, carbon nanotubes (CNTs), and so forth. [13][14][15] There are many studies on polymer-based electromagnetic wave absorbing porous nanocomposites with carbon-based absorbers. Zhang et al [16] prepared polyurethane/GO composite foams by impregnation, and the results showed that the reflection loss of the foam with a density of 0.027 g/cm 3 can reach À46.2 dB as the addition amount of GO was 30%.…”

Superior EMI shielding effectiveness with enhanced electrical conductivity at low percolation threshold of flexible novel ethylene methyl acrylate/single‐walled carbon nanotube nanocomposites

“…Multi-walled CNTs (MWCNTs) have been extensively used as reinforcements due to their relatively low cost and easy availability. [31][32][33][34][35][36][37][38][39][40][41][42] However, a minimal study has been done on singlewalled CNTs (SWCNTs), [43][44][45][46][47][48][49] whereas there is almost no work to date on SWCNT reinforced flexible ethylene methyl acrylate (EMA) polymer matrix nanocomposites.…”