The effects of UV degradation on the physical, thermal, and morphological properties of industrial nylon 66 conveyor belt fabrics

Abstract

In this study, nylon 66 industrial fabrics (used in the conveyor belts) were exposed artificially to the accelerated ultraviolet rays and the degradation mechanism was evaluated using spectral, thermal, and morphological analyses. The fabric samples were exposed to six different exposure times in a UV chamber and tensile tests were carried out in the main and bias (45°) directions. The results showed that the shear modulus was reduced in the early stages covering 4 h of the UV radiation because of the linkages breakage and the increase in the amorphous regions. However, after this early stage, the shear modulus started to increase. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) analysis, and X-ray photoelectron spectroscopy (XPS) study were also performed to evaluate the surface morphology and the degradation mechanism of the nylon 66 fibers after UV illumination. The results also revealed that the formation of new links by free radicals caused the change in the bond wavelengths. Furthermore, it was found that there was an interesting mechanism for the UV degradation of nylon 66 fabrics at different exposure times, as confirmed by the results obtained regarding the mechanical properties of the samples. The results of this study can be, therefore, helpful for the industrial application of nylon 66 woven conveyor belts exposed to solar UV radiation.

A photochromic nylon webbing for ultra-violet light sensing

“…Different from tests in the UV cross-linker, the samples were exposed to UV irradiation continuously for a significantly longer time of 72 h, corresponding to an energy level that could affect the structural integrity of nylon. A similar level of UV irradiation has been observed to induce photooxidation of nylon [38,39], which could result into remarkable losses of mechanical strength [7].…”

“…During their life cycle, webbing structures are often subjected to long-term exposures to sunlight. The ultra-violet (UV) component of sunlight can damage the integrity of webbings made of polymeric fabrics, such as nylon, Kevlar, and polyester, causing degradation in toughness [5], along with tensile [6] and shear strengths [7]. Quantifying the amount of UV energy absorbed by the material is a pivotal aspect of the health monitoring of webbing structures.…”

Insights into the removal of microplastics and microfibres by Advanced Oxidation Processes

“…A recent photocatalytic study reported greater MF degradation efficiency when 254 nm was applied compared to 365 nm (Lee et al, 2020). The application of UV-C lamps (254 nm) resulted in higher carbonyl index values and FTIR results showed more intense peak bands ≈1630 cm −1 compared to the application of UV-A, which correspond to the carbonyl group of the amide groups (NH-C=O) on the fibres after oxidation (Moezzi et al, 2020) (Fig. 5).…”

Photocatalytic Degradation of Polyamide 66; Evaluating the Feasibility of Photocatalysis as a Microfibre-Targeting Technology

“…The band ≈1630 cm −1 may correspond to the carbonyl group from amide groups (NH-C=O) and the reference peak selected was the most intense band from the CH 2 stretching. The reference blank was selected assuming that CH groups may undergo less oxidation and may remain constant [76]. (Figure 12).…”