Efficient photopolymerization of thick pigmented systems using upconversion nanoparticles‐assisted photochemistry

Abstract

Photopolymerization of thick pigmented systems still remains challenging due to the light screening effect of the pigments. Here, we present a facile method based on upconversion nanoparticles (UCNPs)-assisted photochemistry to achieve efficient photopolymerization and improved curing depth of pigmented systems. Under a 980-nm laser irradiation, UCNPs are able to convert NIR light into UV and visible light to activate photoinitiators for the initiation of polymerization. Influencing factors on photopolymerization were systematically investigated. With optimal parameters, 25.5 mm of photopolymerization depth combined with 70% of maximal double bond conversion was obtained. The peak temperature of 120.4 8C during UCNPs-assisted photopolymerization is comparable with or lower than that of some reported frontal photopolymerization applied to prepare functional composite polymeric materials. Both indentation hardness and reduced modulus of the photocured materials using UCNPs as internal lamps were higher than those of the reference cured under traditional blue LED light.

Effect of pigment colour on the printing performance of synthetic leather using a ultraviolet‐curable water‐borne polyurethane acrylate binder

“…The UV light cannot effectively penetrate to the inner layers of the film because of light screening by the pigment particles. When free radicals produced by photoinitiators for the polymerisation did not form effectively, the degree of curing was lowered and the hardness of printed films decreased in the pigmented formulations .…”

Recent progress in the development of upconversion nanomaterials in bioimaging and disease treatment

“…The tricky problem of RNAi therapy is how to effectively protect the siRNA biomolecules from the complex physiological environment and how to increase the delivered expression effect. Yang's research team mounted siRNA on the surface of UCNPs in order to attach anti-Her2 antibodies [ 168 , 169 ]. The release of siRNA could be monitored synchronously through the signal of energy resonance transfer.…”

UV-Cured Poly(Ethylene Glycol) Diacrylate/Carbon Nanostructure Thin Films. Preparation, Characterization, and Electrical Properties

“…A o and A t are the absorbance values of 1634 cm −1 , while A rb and A ra are the values of 1717 cm −1 , before and after curing, respectively [10].…”

“…The advantages of photopolymers include fast curing, high corrosion resistance, and being solvent-free with eco-friendly processes [7][8][9]. Photopolymers are also used as matrices in composite materials with enhanced properties to develop multi-functional characteristics [10].…”