Effect of Curing Strategies on Porosity in Silanemodified Silica Colloidal Coatings

Abstract

Suspensions of silica (20 nim) in propoxyethanol were used to make porous silica coatings. A silane coupling agent, glycidoxypropyltrimethoxysilane (GPS), was added as a binder to increase coating durability and prevent cracking. GPS addition prevented crack formation but only when added in large amounts (GPS to silica weight ratio 0.5 to 1) such that porosity was filled by a GPS-based siloxane polymer. Attempts to enhance the fracture toughness of porous coatings through UV curing and glycol additions failed to lead to improvements in the critical cracking thickness (CCT). However, addition of triethylenetetramine resulted in a 3-fold increase in the CCT. Wear resistance increased for both the UV-cured and amine-cured coatings.

Novel hybrid epoxy silicone materials as efficient anticorrosive coatings for mild steel

“…[8][9][10] Sol-gel derived organic-inorganic hybrid coatings are mainly produced through the hydrolysis and condensation reaction of organofunctional alkoxysilane precursors. 11,12 They were prepared also by the blending of siloxanes with hydrocarbon-based polymers; more notably epoxy resins. 13,14 The corrosion resistance of these coatings has been attributed to their physical barrier properties, which restrict the penetration of the electrolyte towards the metallic substrate.…”

Recent Advancements in Corrosion Protection of Magnesium Alloys by Silane-Based Sol–Gel Coatings

“…However, investigations have discovered the prospects to change and to produce new structures and compositions of hybrid coatings and developed a new range of coating materials. For example, numerous current studies have established a variation in hybrid coatings, executing several ordered structures. , Sol–gel-based hybrid organic–inorganic coatings are chiefly created by means of the hydrolysis and condensation reaction of organo-functional alkoxysilane precursors. , They can also be formulated by the blending of siloxanes with hydrocarbon-based polymers, i.e., epoxy resins . In these systems, the organic part is basically responsible for a rise of the hardness of the coating, while the inorganic component decreases the surface energy and enhances the chemical, thermal, and UV resistance of the systems as well as reducing the overall cost of the materials .…”

Corrosion resistance properties of hybrid organic–inorganic epoxy–amino functionalised polysiloxane based coatings on mild steel in 3·5%NaCl solution

“…epoxy, amino, isocyanate, methacryloyl, or vinyl) and R is an alkyl group, are widely used monomers for the formation of hybrid organic-inorganic coatings. 3,4 The chemical structure and organic functionality of silanes can be varied and optimized to achieve the maximum effect in terms of hydrolytic stability of the interface or desired hydrophobicity or adhesion properties. Epoxy resins represent one of the more popular organic thermosetting polymers and amines are amongst the most common hardners used to catalyse the epoxy ring opening.…”