Solid state 29Si and 11B NMR studies of sol-gel derived borosilicates

Boria Effects on the High Temperature Oxidation of Silicon Carbide

“…Water and -OH species were evolved. Further, the intensities for peaks assigned to borosilicate bonds had increased with TGA exposure, signifying that bonding between Si-O-Si and B-O-B units were enhanced by the evolution of water 72 and increases in temperature 66 . The sol-gel derived borosilicate glasses molecular structure was increasingly like the structure of a binary borosilicate glass with the combination of carbon oxidation and condensations reactions that occurred with the high temperatures exposures in dry O2.…”

“…The limited yield of reacting precursors and the concomitant precipitation of boric acid resulting in boron loss in converted glasses were described early on by Nogami and Moriya 69 . Irwin attributed borosiloxane bond instability in gels to hydrolysis by the presence of water, but spectrally observed the integration of hydrolyzed species into borosilicate bonds with the thermal removal of water 72 . The water and silane ratio were additional factors used to limit boric acid precipitation in the gels 73 .…”

Rational Synthesis Pathway for Ordered Mesoporous Carbon with Controllable 30‐ to 100‐Angstrom Pores

“…This result indicates that borosiloxane bonds (=B-O-Si=) are present and that some boron atoms show tetrahedral coordination to -O-Si groups. [17] These NMR peaks become more resolved in the silica/borosilicate/boron oxide composite material after the removal of carbon (sample G in Scheme 1), as shown in Figure S1. Figure 4 shows XRD patterns and N 2 sorption data for samples corresponding to stages F, G, and H in Scheme 1 (boron content: 8 mol%), which were collected in order to investigate presence as well as thickness of the borosilicate and boron oxide layers on the surface of the mesoporous silica template.…”

Synthesis and characterisation of functionalized borosilicate nanoparticles for boron neutron capture therapy applications

“…This treatment is based on the selective accumulation into the malignant cells of 10 B-containing compounds administrated by intravenous infusion. Subsequent thermal neutron irradiation promotes 10 B decay to one 4 He (a particle) and one 7 Li atom with a cytotoxic effect that can destroy the tumor cell [1]. To date, medical trials of BNCT had been carried out principally with boronophenylalanine (BPA) that showed a good selectivity to malignant cells.…”

“…Nogami and Moriya [8] prepared different compositions of SiO 2 -B 2 O 3 and their study showed that for the sample containing more than 20 mol% B 2 O 3 a quarter of B 2 O 3 was lost during the gel synthesis. The problem of the of Si-O-B bond formation was analyzed by Irwin et al [9,10] by means of 29 Si and 11 B MAS NMR spectroscopy. They showed that the majority of boron atoms in xerogels was in form of boric acid hydrogen-bonded to the silica network, whereas there was only a small amount of B-O-Si bonds.…”