Nanoparticles-Based Phenol-Formaldehyde Hybrid Resins

Abstract

The synthesis, characterization and corrosion properties of a novel material, produced by the reaction of silica nanoparticles with a functionalized Phenol-Formaldehyde Resin (PFR), are presented. Carboxylic groups were attached in situ to the PFR skeleton to produce a functionalized resin (PFR-SA), which is then reacted with sol-gel-prepared silica nanoparticles, yielding a novel hybrid (organic/inorganic) material (PFR-SA-nanoSiO2). This hybrid material was characterized by FT-IR, FT-Raman, TGA, DSC, SEM and corrosion tests, whose results showed significant improvement of the thermal properties in comparison with the PFR coating. In addition, the new material was efficient and durable against corrosion of metals, with the anticorrosive performance of PFR-SA and PFR-SA/nanoSiO2 coating films being superior to those of the original PFR coating.

Synthesis and characterization of Au nanocatalyst on modifed bentonite and silica and their applications for solvent free oxidation of cyclohexene with molecular oxygen

“…The FTIR spectra of modified bentonites as monolayer and bilayer ( Fig. 1b and 1c) display new peaks at 1473-1488, 1577, 2854-2927, and a peak at 2567 cm −1 was attributed to the thiol stretching vibration [18][19][20] which confirms the presence of the thiol groups (Supplementary data).…”

pH-Driven synthesis of collagen-silica nanohybrids

“…It seems that in this solid phase the concentration of SiO 2 is large enough as to induce the segregation of spherical silica from the collagen-silica matrix. The noticeable collagene-SiO 2 crystallization in this sample may be induced by: (i) an excess of OH groups on the surface of SiO 2 particles [13], or (ii) the action of the HCl catalyst, since some of the samples showing SiO 2 crystals were prepared under the presence of HCl.…”

“…Usually, SiO 2 particle-size distributions inside the hybrid media are not too wide and they consist of quasi-spherical micron-size silica particles. The choice of HCl or HN 4 OH catalysts [13] determines their optical (transparency or opacity) properties.…”

“…In every case, a sol could be distinguished at the end of the reaction time, and this colloidal dispersion was stored in a glass flask for nearly 2 months until gelation. Incidentally, the kinetics of this process could be accelerated by the addition of tiny amounts of an inorganic acid, such as HF, HCl or a base such as NH 4 OH [13]. The gels were kept at room temperature and, depending on whether or not an inorganic catalyst was added, either an opaque or a transparent hybrid material was obtained.…”

“…The experimental conditions, such as the low-temperature, the precursor concentration and others, represent an advantage for the synthesis of materials for bioengineering purposes [11,12]. Accordingly, through this technique, a new family of materials has been synthesized, by combining the features of the inorganic sol-gel alkoxide moieties with those of a variety of biological, organic or inorganic species [8,13].…”