Optimum preparation of silanes for steel pre-treatment

Optimisation of wet chemical silane deposition to improve the interfacial strength of stainless steel/epoxy

“…3 shows that increasing the methanol content has a negative influence on APS hydrolysis kinetics, with the time needed for (complete) hydrolysis decreasing from about 10 min to 20 min, 33 min and 72 min for, respectively, a 100/0, 90/10, 70/30 and 50/50 water/methanol solvent. Replacing methanol by ethanol shortens the hydrolysis times to 12 min and 22 min for the 90/10 and 70/30 sample, respectively, as observed before, higher hydrolysis rates at higher water contents [22,35,36]. The same phenomenon was observed in glycidoxypropyltrimethoxy-silane (GPS) solutions, where the reduced polarity of ethanol compared to water explained the slower kinetics of alcohol rich solvents [36].…”

“…Replacing methanol by ethanol shortens the hydrolysis times to 12 min and 22 min for the 90/10 and 70/30 sample, respectively, as observed before, higher hydrolysis rates at higher water contents [22,35,36]. The same phenomenon was observed in glycidoxypropyltrimethoxy-silane (GPS) solutions, where the reduced polarity of ethanol compared to water explained the slower kinetics of alcohol rich solvents [36]. Note that amino functionalised species, such as APS, hydrolyse rather fast compared to silanes with other functional groups due to the autocatalytic effect of the amino-functionality [37,38].…”

“…Dimers are present from the very start for 2 v% APS in methanol based solvents. This may be due to the higher polarity of methanol compared to ethanol [36]. A 2 v% APS solution in a 90/10 water/ethanol solvent thus seems to combine a reasonably fast hydrolysis with limited self-condensation over a long time.…”

Ultra-high performance fibre-reinforced cementitious composite with steel microfibres functionalized with silane

“…Silane concentrations of 1.0% by volume are typically used for industrial functionalization of metallic plates with amino, ureido and epoxysilanes [35][36][37]. For the functionalization of synthetic fibres, [29] and [30] used concentrations of 0.5%, 0.75% and 1.0% by volume of vinylsilane.…”

Monitoramento da hidrólise/condensação do tetraetoxisilano em solução com baixo teor alcoólico por análises de espectroscopia de infravermelho

“…Além disso, a taxa de hidrólise tende a ser cada vez menor, pelo fato dos grupos Si-OH assim que formados, tenderem a condensar com os silanóis disponíveis. Apesar da desaceleração, verificou-se pela banda 1167 cm -1 que a condensação dos silanóis continua, porém em velocidades lentas, também verificado por Cunliffe et al [25].…”