scholarly journals Wood Protective Coatings Prepared with Silanes Based on Fatty Acids

2020 ◽  
Vol 2 (1) ◽  
pp. 24
Author(s):  
Karol Szubert

Wood is one of the most important materials in the construction industry. Because of its organic constitution, it is slowly destroyed by the long-term impacts of water, oxygen and light under atmospheric conditions and, hence, needs to be sufficiently protected. Appropriate protection of wood leads to it having longer life and, hence, a huge reduction in maintenance costs. There are several methods to protect wood, either by its chemical modification or by its surface treatment. Unfortunately, many of the wood preservatives that have been used so far are highly toxic to humans and, hence, much attention has been paid to the development of nontoxic materials/methods for the protection of wood. Recently, several reports have been published on the use of inorganic–organic hybrid coatings for the protection of wood substrates. The sol–gel process to generate hybrid coatings is quite versatile and even allows room temperature deposition of hybrid inorganic–organic films on a wide range of substrates, including wood. Wood surface modification with multifunctional alkoxysilanes by the sol–gel process is one promising method to improve and provide new properties for wood materials. The advantage of the sol–gel process is that it allows deposition of a thin inorganic–organic layer on various substrates as a result of controlled hydrolysis and polycondensation of alkoxysilanes. The sol–gel coatings created on the wood surface provide barrier properties, moisture control and repellency properties. In this communication we present new trialkoxysilanes synthesised from fatty acid derivatives and their application in wood protective coatings.

2010 ◽  
Vol 1278 ◽  
Author(s):  
L.L. Díaz-Flores ◽  
A. S. López Rodríguez ◽  
P. SifuentesGallardo ◽  
M.A. Hernàndez Rivera ◽  
M.a Garnica Romo ◽  
...  

AbstractThis work is about the production of hybrid coatings of the system SiO2-PMMA (PMMA, polymethylmethacrylate). These materials have interesting mechanical and chemical properties useful for anticorrosive and wear resistance applications. SiO2-PMMA hybrids were obtained by the sol-gel traditional process, using tetraethylorthosilicate (TEOS) and methylmethacrylate (MMA) by Aldrich Co, as starting reagents. The SiO2:PMMA ratio was varied from 0:1 to about 1:1 at air atmosphere deposition. The coatings were obtained on acrylic sheets and silicon wafers. A diversity of coatings with chemical composition ranging from SiO2 and PMMA to obtain the SiO2-PMMA hybrids were obtained. Infrared (IR) and atomic force microscopy (AFM), were performed to determinate structural and morphological behavior.


2018 ◽  
Vol 47 (9) ◽  
pp. 2925-2932 ◽  
Author(s):  
J. Brendlé

The sol–gel process involving hydrolysis and condensation reactions is an attractive way to form siloxane based hybrid materials since it is a one-step method performed under mild conditions.


2003 ◽  
Vol 780 ◽  
Author(s):  
Xinshi Luo ◽  
Congji Zha ◽  
Barry Luther-Davies

AbstractPhotosensitive organic-inorganic hybrid polymers were synthesised for integrated optical and optoelectronic devices by a non-hydrous sol-gel process of hydrolysis/condensation of 3-methacryloxypropyltrimethoxysilane (MPS), diphenyldimethoxysilane (DPhDMS), and zirconium isopropoxide (TPZ) with boric acid under anhydrous conditions. The methacryl groups of MPS are UVpolymerizable, which are suitable for low cost fabrication of waveguides with a “UV write/develop” process. The incorporation of DPhDMS and TPZ was found useful in reducing the optical loss and in enhancing the thermostability of the polymer. The refractive index of the hybrid polymer is tuneable from 1.4950 to 1.5360 by variation of the ratio among MPS, DPhDMS and TPZ. Optical characterisation showed that the material has low optical losses at the telecommunications windows (0.16 dB/cm at 1310 nm and 0.4 dB/cm at 1550nm). The hybrid polymer also showed a low birefringence (1.2×10-4), a large thermo-optic (TO) coefficient (-2.77 ×10-4), and an outstanding linearity of dn/dT in a wide range of temperature (from 25 °C to 200 °C). Waveguides forming ability for the hybrid polymer with UV imprinting was also demonstrated.


2012 ◽  
Vol 16 ◽  
pp. 1-7
Author(s):  
Nazanin Farhadyar ◽  
Mirabdullah Seyed Sadjadi

In this paper, we report preparation of hydrophilic hybrid nanocomposite coatings on glass substrates using Zinc acetate solutions based on 3-glycidoxypropyltrimethoxysilane (GPTMS), epoxy resin, aromatic amine (HY850), polyethylene glycol (PEG) and surfactant (polyoxyethylene(4)laurylether) by the sol-gel process. Furthermore, the effects of PEG addition to the precursor solutions on the hydrophilic property and microstructure of the resultant coating film were studied. The hydrophilic behavior study of the synthesized hybrid was performed by adding different amounts of polyethylene glycol precursor to the hybrid solution. Experimental results show that, among different amounts of PEGs, the best results are obtained by addition of PEGs (400) to the hybrid solution which can decrease the water contact angles down to 16 and using surfactant down to 0, and increase the free surface energy. Coated glass exhibits a higher strength than uncoated glass. Attenuated total reflectance infrared spectroscopic (ATR-IR) technique was used to characterize the structure of the hybrid films. The chemical structure of obtained network affects morphology of the coating. The morphology of the hybrid coatings was examined by transmission electron microscopy (TEM). The hybrid systems have a unit form structure and the inorganic phases were in the nanosize scale,


Author(s):  
Stefan Holberg

This chapter focuses on resins based on non-hydrolyzed, monomeric and polymeric alkoxysilanes. As alternative to classical sol-gel processing, the resins are applied to a surface without a preceding hydrolysis step. Only after application, hydrolysis and condensation of the alkoxysilyl groups occur by means of atmospheric moisture to result cross-linked organic-inorganic hybrid coatings. While the use of non-hydrolyzed silanes is well established, for example by applying polyethyl silicate as binder for zinc-rich anti-corrosive primers, this chapter describes the chemical structures of various novel organic-inorganic hybrid precursors that have significantly extended the area of application to adhesives and scratch-resistant, repellent, or anti-fouling coatings. At present, individual resins are produced and applied at industrial scale in the fields of protective coatings and automotive topcoats.


2006 ◽  
Vol 951 ◽  
Author(s):  
Katsunori Nishiura ◽  
Toshihiko Takaki ◽  
Makoto Nakaura

ABSTRACTIt is important to develop flexible transparent polymer films having high gas barrier properties and abrasion resistance because new applications involving transparent polymer films for flat panel displays require these properties. We report on organic-inorganic hybrid coatings of polyvinylalcohol (PVA)/polyacrylicacid (PAA)-silica, which have high gas barrier properties almost equivalent to those achieved by the dry coating process. The hybrid coatings were prepared by the sol-gel reaction of alkoxysilane in a PVA/PAA aqueous solution. In order to obtain transparent coating films, 3-aminopropyltrimethoxysilane (APTMOS) was used as a compatibilizer in the sol-gel reaction of tetramethoxysilane (TMOS). No structure could be seen in the TEM of the cross-sectional coating layer, indicating that polymers and silica were mixed homogeneously. PVA/PAA-silica hybrid coatings were shown to have excellent abrasion resistance based on the ΔHaze index. O2 permeability of PVA/PAA-silica hybrid coatings evaluated by MOCON under the conditions of 23°C, 90% RH was lower than that of PVA/PAA polymer coating, which suggests that silica affects the barrier property of the hybrid coating in humid conditions. Furthermore, O2 permeability decreased as silica content increased in the coatings. Unexpectedly, high gas barrier properties appeared when the silica content exceeded 50 wt%. From the result of element distribution analysis measured by EF-TEM, it was confirmed that phase separation occurred between PVA/PAA and silica on a nanometer scale and silica forms continuous structures, which are considered to suppress O2 permeability.


2011 ◽  
Vol 258 (2) ◽  
pp. 806-810 ◽  
Author(s):  
Shuliang Wang ◽  
Changyu Liu ◽  
Guochao Liu ◽  
Ming Zhang ◽  
Jian Li ◽  
...  
Keyword(s):  
Sol Gel ◽  

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 2021 ◽  
Author(s):  
M. Clara Gonçalves

Silica is one of the most abundant minerals in the Earth’s crust, and over time it has been introduced first into human life and later into engineering. Silica is present in the food chain and in the human body. As a biomaterial, silica is widely used in dentistry, orthopedics, and dermatology. Recently amorphous sol-gel SiO2 nanoparticles (NPs) have appeared as nanocarriers in a wide range of medical applications, namely in drug/gene target delivery and imaging diagnosis, where they stand out for their high biocompatibility, hydrophilicity, enormous flexibility for surface modification with a high payload capacity, and prolonged blood circulation time. The sol-gel process is an extremely versatile bottom-up methodology used in the synthesis of silica NPs, offering a great variety of chemical possibilities, such as high homogeneity and purity, along with full scale pH processing. By introducing organic functional groups or surfactants during the sol-gel process, ORMOSIL NPs or mesoporous NPs are produced. Colloidal route, biomimetic synthesis, solution route and template synthesis (the main sol-gel methods to produce monosized silica nanoparticles) are compared and discussed. This short review goes over some of the emerging approaches in the field of non-porous sol-gel silica NPs aiming at medical applications, centered on the syntheses processes used.


2014 ◽  
Vol 77 (11) ◽  
pp. 1635-1641 ◽  
Author(s):  
Rosa Taurino ◽  
Elena Fabbri ◽  
Doris Pospiech ◽  
Alla Synytska ◽  
Massimo Messori

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