Evaluation of bisphenol A-based epoxy resin containing multiwalled carbon nanotubes to improve resistance to degradation

Abstract

The influence of exposure to UV light and moisture on the durability of a multiwalled carbon nanotube(MWCNT)/epoxy nanocomposite was investigated. Samples of epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) cured with 2,2,4-trimethylene-1,6-hexadiamine (TMDA), and epoxy nanocomposite containing 0.5% MWCNT were exposed to different accelerated weathering times between one and six months. Changes in surface chemistry, mechanical properties (tensile tests), thermal properties (thermogravimetric analysis and differential scanning calorimetry), and morphology were evaluated before and after exposure to accelerated weathering for a period of up to six months. Epoxy nanocomposite (DGEBA–TMDA/0.5%MWCNT) samples had improved thermal stability and resistance to degradation, compared to epoxy resin (DGEBA–TMDA). The effect of MWCNT at reducing degradation was more pronounced than previously found for resins prepared with hydrogenated DGEBA.

Effects of UV radiation on natural and synthetic materials

“…When exposed under a UV radiation source (six spectral UVA-365 lamps with nominal wavelength 365 nm, Worldwide Specialty Lamp, Austell, GA), yielding 0.77–0.95 W m −2 nm −1 to comply with the ASTM specification of 0.89 W m −2 nm −1 , for 2160 h, in cycles of exposure (4 h light and 4 h darkness) the filled composites showed very good UV resistance as evidenced by the absence of microcracks typically observed in untreated composite samples. Epoxy nanocomposites that contain 0.5 wt% multiwalled carbon nanotubes (MWCNTs) (outer/inner diameter < 20 nm/4 nm, length 1–12 μm) dispersed in the resin that was based on diglycidyl ether of bisphenol A (DGEBA) and cured with 2,2,4-trimethylene-1,6-hexadiamine (TMDA) [ 140 ] have been studied. These were subjected to accelerated weathering under UV-A lamps (140 W m −2 over 295–400 nm range) in alternating humidity and temperature conditions for a total irradiation time of 1–6 months.…”

Synthesis, Characterization and Thermal Properties of Photoresponsive Epoxy Resin Containing Benzylidene Units in the Main Chain

“…The broad band at 3420 cm-1 is attributed for the vibrations of the hydroxyl group and a strong band at 2923 cm -1 is due to the C-H stretching vibrations. 1 H-NMR spectrum of the resulting epoxy resin is shown in Figure 2(a). In this spectrum, the characteristic proton resonances of the oxirane ring appeared as a singlet signal at 3.26 ppm which is assigned to CH (methine), and the signal at 2.67 ppm is assigned to CH2 (methylene).…”

“…Many properties such as, high photosensitivity, film forming ability, good solubility before irradiation changed to resistance toward solvents, plasmas, and etching agents after UV exposure and thermal stability are very important for a photopolymer to be used as a photoresist (Balaji, Grande, & Nanjundan, 2004;Reiser, 1989). Evaluation of Epoxy nanocomposites to improve resistance to degradation was reported by (Awad, Fellows, & Mahini, 2019), the epoxy nanocomposite containing 0.5% MWCNT had improved thermal stability and resistance to degradation compared to the bare epoxy resin. A novel and facile strategy was suggested by (Yao et al, 2015), to make a thermosetting epoxy resin/thermoplastic system with both shape memory and self-healing properties.…”

Cryogenic mechanical properties and failure mechanism of epoxy nanocomposites modified by multiwalled carbon nanotubes with tunable oxygen‐containing groups on surface

“…And TGA of the MWCNT (solid line in Figure 5) showed a slight mass loss at 380 C, corresponding to the decomposition of E51. [34] While the initial decomposition temperature of MWCNT was about 600 C in N 2 atmosphere. [35] In contrast, distinct weight loss at 380 C was observed in TGA of OMCNT-2.21, OMCNT-3.42, and OMCNT-4.20 (short dash, short dash dot, and dot lines in Figure 5).…”