Different Approaches to Oxygen Functionalization of Multi-Walled Carbon Nanotubes and Their Effect on Mechanical and Thermal Properties of Polyamide 12 Based Composites

Abstract

In this work the preparation of polyamide 12 (PA12) based composites reinforced with pristine and surface-modified carbon nanotubes is reported. A qualitative and quantitative evaluation of multi-walled carbon nanotube functionalization with oxygen containing reactive groups achieved by different procedures of chemical treatment is presented. Simple strong oxidative acid treatment as well as chlorination with subsequent chloroacetic acid treatment were applied. Carbon nanotubes (CNTs) were also subjected to chlorine and ammonia in gaseous atmosphere with small differences in after-ammonia treatment. Commercial COOH-functionalized carbon nanotubes were compared with nanotubes that were laboratory modified. The effect of CNT functionalization was evaluated basing on the improvement of mechanical and thermal properties of polyamide 12 composites prepared by in situ polymerization. It was found that high concentration of oxygen-containing functional groups on nanotube surface is not sufficient to improve the composite performance if the structure of carbon nanotubes is defective. Indeed, the best effects were achieved for composites containing nanotubes modified under mild conditions, seemingly due to a compromise between morphology and surface chemical structure.

Recent advances and applications to cultural heritage using ATR-FTIR spectroscopy and ATR-FTIR spectroscopic imaging

“…In the two spectra, the important differences reside in the relative intensities of the band in the region 3000-2800 cm −1 (C-H stretching) and the position of the amide II band (N-H bending and C-N stretching). 128,129 The main constituents of natural textile fibres such as cotton, silk, wool, hemp and flax are proteins, leading to an apparently similar spectral pattern. However, FTIR spectroscopy is also useful for identification of natural textile fibres by comparing different types of proteins these fibres possess.…”

Influence of the addition of multi‐walled carbon nanotubes on the thermal and mechanical properties of polyamide‐11 before and after aging tests

“…As for the loss modulus E", the nanocomposite with 0.5% of silanized nanofiller (PANTS05) also obtained the highest value, with all other nanocomposites having values lower than PA11 56 . The obtained results indicate that the energy dissipation for PANTS05 is higher than in the other nanocomposites, as well as for unfilled PA11, and the increase in dissipation may be related to the high surface area of the MWCNT nanoparticles.…”

“…The significant improvement in the E' value of nanocomposite with 0.5% nanofiller (both oxidized and silanized MWCNTs), meaning the increase of the material's stiffness, is attributed to the combination of the nanoparticles' strong reinforcement and dispersion effect 56 . It is possible, then, to conclude that the use of 0.1 wt% of nanofillers was not enough to increase the storage modulus.…”

Emerging Research in Conductive Materials for Fused Filament Fabrication: A Critical Review

“…The same approach can also be extended to other thermoplastics like PP [ 187 ] and PA12. [ 188 ] The effect of functionalizing CNTs with acids is not removed when melt compounding and therefore this method is suitable for use in FFF filament production. Besides improving the affinity to thermoplastics, chemical side groups such as carboxyl groups (COOH) (shown in Figure ) aid in dispersion in polar solvents.…”