Effect of surface modification on the compressive properties of silica fume/polyurethane composites

Abstract

<jats:title>Abstract</jats:title> <jats:p>Silica fume was modified by a silane coupling agent (KH-550). The modified silica fume was further investigated to reinforce polyurethane (PU) composites. Unmodified and modified silica fume reinforced PU composites were prepared. Through the comparisons of Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) of unmodified and modified silica fume, the agglomerations of silica fume particles were effectively prevented as KH-550 was grafted. The compressive strength of the modified silica fume/PU composites was largely improved, because KH-550 could react with both silica fume and PU. Meanwhile, modified silica fume turned from hydrophilic to hydrophobic; a better dispersion was realized in the PU elastomers compared to the unmodified silica fume. The reinforcement effects were evaluated based on the results of a universal test machine in comparison with unmodified silica fume/PU composites.</jats:p>

Efeito da ultrasonicação da sílica ativa e da nanossílica coloidal em pastas de cimento

“…Apesar do crescente número de pesquisas que utilizaram esses métodos para dispersar a SA [18][19][22][23][24][25] e a NS [26][27][28][29][30][31][32], não foram encontrados estudos que avaliaram o efeito da ultrasonicação da NS coloidal na microestrutura de materiais cimentícios. Isso representa uma lacuna importante para a comunidade científica atualmente, tendo em vista que o sistema coloidal pode não garantir a total dispersão das partículas de NS e o tamanho das partículas de NS influencia diretamente nas propriedades dos materiais cimentícios [5,17].…”

Modified Silica Incorporating into PDMS Polymeric Membranes for Bioethanol Selection

“…However, because of the existence of a broad range of hydroxy groups on its surface, the fumed silica nanoparticles in the PDMS matrix would form agglomerations resulting in the uneven distribution. It is therefore of great necessity to treat the surface of silica with chemical methods [21,22]. Typically, silane coupling agents have been employed to enhance the hydrophobic property of silica in light of their bifunctional groups [15,23,24].…”