Novel Waterborne Polyurethane Adhesives Based on Ag@SiO₂Nanocomposites

Abstract

In this work, the use of silver-based silica nanocomposites (Ag@SiO 2 ) was proposed to inhibit the microorganism growth of waterborne polyurethane adhesives. For that purpose, colloidal silver nanoparticles were prepared and embedded in a SiO 2 -based matrix in order to decrease the silver aggregation tendency. The protection of AgNPs with silica was also intended to improve the stability of the adhesive toward metallic particles. Last but not least, Ag@SiO 2 provides safer handling of the silver nanoparticles due to their immobilisation within the silica matrix. Colloidal silver was prepared by the Creigthon method using NaBH 4 as a reducing agent and polyvinylpyrrolidone (PVP) as a stabilising agent. The coating of the AgNPs by the silica matrix was achieved through a modified Sto¨ber process. The stability of the AgNPs in different amino-based catalysts for the silica matrix synthesis was evaluated in order to successfully obtain silversilica core-shell nanocomposites. After that, AgNPs and Ag@SiO 2 nanocomposites were incorporated in a waterborne polyurethane adhesive and the chemical, thermal adhesion and antimicrobial properties were evaluated.

Measurement and modeling of the effective thermal conductivity of sintered silver pastes

“…This is particularly important in electronic devices, whose performance, power, lifetime, and miniaturization rely on the effective dissipation of heat. [1][2][3][4][5][6][7][8][9] TIMs provide mechanical strength to the junction between a heat sink and a heat source, and their thermal conductivity represents the bottleneck for the heat flow through the mating surfaces, which are usually not smooth neither at the same temperature. Among the wide variety of TIMs (e.g.…”

Effect of the surface treatment in polyurethane and natural leather for the footwear industry

“…The selection of an optimum adhesive for the adhesive joint is not always an easy task because the materials differ and, in many cases, the materials selected for construction of a shoe model are subjected to surface treatments, which increases the complexity of the manufacturing process but provide a better union of the materials .…”