(I/O) Hybrid Alkoxysilane/Zirconium-Oxocluster Copolymers as Coatings for Wood Protection

Abstract

Novel inorganic-organic hybrid copolymers based on vinyl- or (3-mercaptopropyl)-trimethoxysilane and an organically modified zirconium-oxocluster were investigated as a wood preservation treatment. The copolymers were prepared using a modified sol-gel strategy not involving alkoxysilane pre-hydrolysis and were applied on wood through a dip coating method. Even though the copolymers were mainly present on the surface of the wood, EDX analysis showed also a uniform distribution of silicon and zirconium in the cell wall but not in the lumina. The grafting of the copolymers on wood was confirmed through FTIR, (13)C and (29)Si MAS NMR analysis. The copolymer obtained from (3-mercaptopropyl)trimethoxysilane was post-functionalized with the methacrylic ester of thymol; introduced for testing as a biocide. Preliminary accelerated biological tests against the brown rot fungus Coniophora puteana, showed resistance to the fungus for the samples coated with the vinyltrimethoxysilane copolymer, while uneven results were obtained for the samples coated with the (3-mercaptopropyl)trimethoxysilane copolymer, even when functionalized with the ester of thymol.

Polymer grafts on zirconia particles and their application as supports of hybrid catalyst

“…In all cases, the substrates were consumed smoothly and could reach complete conversion. More importantly, the hybrid catalysts did not exhibit significant reaction velocity decrease in comparison to a homogeneous catalytic system using PW 12 as the catalyst, which is consistent with previous studies using other catalyst immobilization approaches. 52,53 After completion of each oxidation reaction, the hybrid catalyst was separated from the reaction mixture by centrifugation and the upper solution was subjected to work-up and purification (column chromatography) to afford the corresponding products.…”

“…PW 12 in bulk form presents suitable properties to be used as a catalyst in a series of oxidation reactions. The catalytic potential of the prepared hybrid system PW 12 -P4VP-ZrO 2 was tested by five different oxidation reactions: (1) oxidation of 2-hydroxyaniline to 2-hydroxynitrobenzene, (2) oxidation of benzylamine to benzaldoxime, (3) oxidation of diphenylsulfide to dibenzothiophene sulfone, (4) oxidation of cyclohexanol to cyclohexanone and (5) oxidation of cyclohexene to epoxycyclohexane.…”

“…strong acid, alkalis, organic and inorganic dissolving agents, make the bonding between ZrO 2 and other synthetic materials difficult to establish compared with that between ceramic materials such as silica‐based ceramics with counterparts . Traditional methods including physical treatment under harsh conditions or chemical reactions using surface modifying agents such as carboxylic acids and silanes have been established . However, some of these surface modifiers suffer from limitations, e.g.…”

“…TGA curves of pristine ZrO 2 (curve A), P4VP grafted ZrO 2 (curve C), PW12 immobilized P4VP grafts (curve D) and P4VP (curve B).…”

Hybrid Materials Based on the Embedding of Organically Modified Transition Metal Oxoclusters or Polyoxometalates into Polymers for Functional Applications: A Review

“…By using this general approach, not only bulk hybrid materials could be obtained, but also porous and mesoporous structures, as well as thin/thick hybrid coatings and films[16,101–114]. …”