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<p>A method for synthesizing copper nanoparticles (CuNPs) immobilized on astralenes (Astr) or silicon dioxide (SiO<sub>2</sub>), using ascorbic acid or formalin as reducing agents, is presented. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses demonstrate that the CuNPs/Astr system reduced with ascorbic acid yields homogeneous, nearly spherical nanoparticles with an average size of ~ 59&#xa0;nm, a narrow size distribution, and minimal agglomeration. Opposite, the use of formalin results in irregular, elongated particles (up to 800&#xa0;nm) and partial oxidation to Cu<sub>2</sub>O/CuO. CuNPs on SiO<sub>2</sub> exhibit larger particle sizes (103–112&#xa0;nm) and show reduced sensitivity to the reducing agent, likely due to spatial confinement within the porous matrix. Scherrer analysis confirms the smallest crystallites (34&#xa0;nm) for the ascorbic acid – reduced CuNPs/Astr system. Incorporation of CuNPs/Astr into an acrylate matrix at a concentration of 0.05 wt% moderately decreases the photopolymerization rate (maximum rate ~ 6%/s compared to ~ 13%/s for the neat system) without affecting the monomer conversion, thereby potentially reducing internal stresses. The composite exhibits a decrease in ultraviolet (300–450&#xa0;nm) transmittance while maintaining high transparency (&gt; 89%) in the visible and near-infrared regions. This behavior is attributed to the combined effect of surface-oxidized copper particles and the π-conjugated Astr framework. Optical microscopy confirms uniform nanoparticles distribution without visible agglomeration. Thermal analysis reveals delayed thermal degradation with no significant change in the glass transition temperature. Overall, the CuNPs/Astr system synthesized using ascorbic acid represents an efficient transparent nanofiller for UV-filtering optical coatings and optoelectronic components.</p>

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Copper nanoparticles on astralenes: Influence on the kinetics of acrylates photopolymerization and properties of polymer composites

  • 期刊论文

  • 发表日期：

    2026年3月11日

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  • Vladislav N. Kuzmin,
  • Valentine E. Tarasov,
  • Julia A. Burunkova,
  • Attila Csík,
  • Dmitry M. Dolgintsev

摘要

A method for synthesizing copper nanoparticles (CuNPs) immobilized on astralenes (Astr) or silicon dioxide (SiO2), using ascorbic acid or formalin as reducing agents, is presented. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses demonstrate that the CuNPs/Astr system reduced with ascorbic acid yields homogeneous, nearly spherical nanoparticles with an average size of ~ 59 nm, a narrow size distribution, and minimal agglomeration. Opposite, the use of formalin results in irregular, elongated particles (up to 800 nm) and partial oxidation to Cu2O/CuO. CuNPs on SiO2 exhibit larger particle sizes (103–112 nm) and show reduced sensitivity to the reducing agent, likely due to spatial confinement within the porous matrix. Scherrer analysis confirms the smallest crystallites (34 nm) for the ascorbic acid – reduced CuNPs/Astr system. Incorporation of CuNPs/Astr into an acrylate matrix at a concentration of 0.05 wt% moderately decreases the photopolymerization rate (maximum rate ~ 6%/s compared to ~ 13%/s for the neat system) without affecting the monomer conversion, thereby potentially reducing internal stresses. The composite exhibits a decrease in ultraviolet (300–450 nm) transmittance while maintaining high transparency (> 89%) in the visible and near-infrared regions. This behavior is attributed to the combined effect of surface-oxidized copper particles and the π-conjugated Astr framework. Optical microscopy confirms uniform nanoparticles distribution without visible agglomeration. Thermal analysis reveals delayed thermal degradation with no significant change in the glass transition temperature. Overall, the CuNPs/Astr system synthesized using ascorbic acid represents an efficient transparent nanofiller for UV-filtering optical coatings and optoelectronic components.