The use of UV LEDs as an alternative to mercury or fluorescent lamps is gaining rapid momentum for curing applications in the middle UVA range.uv curing cob This technology is environmentally friendly, with no mercury, and also offers significant advantages in terms of cost, system miniaturization and increased efficiency.uv curing cob However, proper measurement and characterization of UV curing is crucial to the successful adoption of this new technology.
This article addresses the issues involved in measuring UV curing, specifically in the middle UVA range, and discusses the challenges posed by the different measurement techniques available.uv curing cob It highlights some of the advantages of UV LEDs, and explains how to achieve optimal performance using these devices.uv curing cob
In this paper, the authors have investigated the effect of various carbonaceous fillers (MWCNTs and biochar) on the physico-mechanical properties of UV-LED curable acrylate networks.uv curing cob The effect of the fillers on the flexural strength and hardness of the cured polymer was assessed by means of mechanical tests, and the optical properties were evaluated through UV-Vis spectroscopy and transmittance measurements over a wide wavelength range.
The results showed that the addition of carbonaceous fillers significantly increases the flexural strength of the UV-LED cured networks, but has little impact on their hardness.uv curing cob The mechanical sensitivity of the networks to shear was not affected by the presence of the carbonaceous fillers, and they maintained high transparency over a wide wavelength range, even at 1.0 wt% of biochar, despite the fact that the polymer chains are frozen in a non-equilibrium thermodynamic state after the UV-LED irradiation.
Besides the physico-mechanical and optical characteristics, the researchers also studied the influence of the carbonaceous fillers on the UV-LED curing kinetics, by examining the FTIR-ATR spectra of the samples before and after exposure to UV-LED radiation.uv curing cob The authors observed that, in the case of systems containing MWCNTs and biochar at various loadings, the disappearance of the band at 1630 cm-1 (attributed to the acrylic double bonds) was a good indicator of the completeness of the conversion to oligomers, as confirmed by the fast curing rate measured under UV-LED radiation. The oligomers formed by the MWCNTs and biochar were found to have high barrier properties against oxygen diffusion, as indicated by the low oxygen permeability values obtained for the cured networks. This indicates that the UV-LED irradiation promotes the formation of oligomers with well-defined molecular architectures, which enhances the elasticity and resilience of the networks. This, in turn, increases their mechanical permeability and resistance to stress, making them an interesting material for application as an adhesive in industrial applications. The synthesis of these compounds can be easily carried out using microwave-assisted chemical vapor deposition, and the authors suggest that their application could have broad applications in the field of electronics and plastics.
