Cure study of epoxy resin reinforced with multiwalled carbon nanotubes by Raman and luminescence spectroscopy

Abstract

Carbon nanotubes (CNTs) were annealed at high temperature under vacuum, followed by a chemical treatment using acids and ethylenediamine. The presence of acid and amine chemical groups on CNT surface was confirmed by infrared spectra. The amount of iron remaining in the CNTs after the treatments was evaluated by thermogravimetry and by energy dispersion spectroscopy. The crystalline property of CNTs was evaluated by Raman spectroscopy, showing that the acid treatment performed after the thermal treatment did not damage the nanotubes walls. Micrographs showed that the most dispersed CNTs were obtained after the amine functionalization step. The curing process of the neat resin and composites was studied by Raman and Luminescence spectroscopies and both techniques showed similar results. The presence of CNTs, functionalized or not, increased the cure degree of the epoxy resin when the same cure time was used in the comparison. Nanocomposites synthesized with annealed CNT and acid-treated CNT had cure rates considerably higher at the beginning of the reaction. The difference in the cure rate was explained by means of the sample's homogeneity and the presence of chemical groups.

Functionalization of Multi-Walled Carbon Nanotube and Mechanical Property of Epoxy-Based Nanocomposite

“…4a and 4b that the adding of CNT in the resin without surface modification produces a slight increase in the average hardness from 21.33 to 21.69 HV (significantly same values; p-value = 0.487). It is known that functionalized CNTs have more disorganized microstructure compared to pristine CNT, which leads to greater dispersion of CNTs, hence functionalized CNTs have better interfacial bonding with the polymer matrix (Cividanes et al 2012). In addition, Figs CNT-H CNT-Ac On the other hand, it appears that CNT additions significantly increase the composite sample variability in the hardness (p-value < 0.001).…”

“…In addition, Figs CNT-H CNT-Ac On the other hand, it appears that CNT additions significantly increase the composite sample variability in the hardness (p-value < 0.001). The high variability of the hardness results may be attributed to CNTs dispersion in the polymer matrix, which can affect the final nanocomposite properties (Song and Young 2005;Bal and Samal 2006;Cividanes et al 2012).…”

Surface Modification of Carbon Nanotubes for High-Performance Polymer Composites

“…Therefore, a key requirement for improved processing techniques for epoxy/CNT composites is the prevention of nanotube aggregation. Various investigations focusing on methods of mixing CNTs into the polymer matrix have been reported in the literature [112][113][114][115][116][117][118][119][120][121].…”

“…SEM micrographs showed that amine-functionalized CNTs had more disorganized microstructures, which led to greater dispersion of CNTs [121]. [90].…”

Carbon nanotube functionalized with dodecylamine for the effective dispersion in solvents

“…Chemical functionalization by adding functional groups to the CNT surface is one of the most recognized and effective way to overcome these drawbacks [19]. Functional groups can be carboxyl, amino or alkane groups, which are not only an effective way to prevent the agglomeration, but also to improve the miscibility of CNTs with matrices by enhancing interfacial interactions through chemical bondings [14,20,21]. Furthermore, chemical modification broadens considerably the potential to develop new functional materials, structures and devices, for interesting and promising applications in various fields, including nanocomposites [22], sensors [23] and biomedical materials [24], due to the high reactivity and interesting chemical properties of the functionalized CNTs [25].…”