Mixed metal oxide inorganic/organic coatings

Mixed metal oxide ceramer coatings were developed using linseed oil as the organic phase with titanium i-propoxide, and zirconium n-propoxide as the inorganic sol-gel precursors. The overall goal of this study was to develop a primer that will provide corrosion protection and better adhesion to metal substrates with minimal environmental impact. Zinc acetate dihydrate was introduced to the system as an anticorrosive agent. Various coatings properties such as adhesion, hardness, impact resistance, flexibility, and tensile properties were investigated as a function of sol-gel precursor type and content. In addition, electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion properties of these mixed metal oxide inorganic/organic coatings. Department of Polymers and Coatings, Fargo, ND 58105.     

Synergistic effect of driers on soybean oil-based ceramer coatings

Inorganic-organic hybrid coatings were prepared using blown soybean oil with sol-gel precursors. Three sol-gel precursors, titanium tetra-i-propoxide (TIP), titanium (di-i-propoxide) bis (acetylacetonate) (TIA), and zirconium tetra-n-propoxide (ZrP) were used in conjunction with cobalt, manganese, and zirconium driers. The goal of this study was to investigate if a synergy exists between the drier and sol-gel precursors with respect to the autooxidation process. Various coating properties such as hardness, adhesion, reverse impact resistance, and flexibility were evaluated as a function of sol-gel precursor and drier content. Viscoelastic and tensile properties were also investigated. Department of Polymers and Coatings, Fargo, ND, 58105.     

Ternary evaluation of UV-curable seed oil inorganic/organic hybrid coatings using experimental design

Inorganic/organic hybrid coatings were prepared using epoxidized linseed oil with combinations of the two sol–gel precursors (titanium(IV) isopropoxide, tetraethyl orthosilicate), and a telechelic silicate based on a modified oligomeric caprolactone. The coatings were UV-cured with sulfonium initiators which concomitantly cured the epoxy functional organic phase and the sol–gel inorganic phase to form a co-continuous inorganic/organic system. A ternary experimental design was employed to elucidate the influence of inorganic modifier on the mechanical properties of the inorganic/organic hybrid coatings. Small angle X-ray scattering (SAXS) was used to evaluate radius of gyration of the metal-oxo-cluster. Various coating properties, such as hardness, impact resistance, adhesion, solvent resistance, and surface energy were investigated as a function of sol–gel precursors. Inorganic/organic hybrid coatings containing both tetraethyl orthosilicate and the modified caprolactone resulted in improved hardness and solvent resistance with no loss of impact strength. The inclusion of titanium(IV) isopropoxide in to the systems resulted in a systematic reduction in the coatings properties. This was attributed to inhibition of the organic crosslinking process as a consequence of absorption of ultraviolet light by the titanium-oxo-clusters.     

Synthesis and characterization of abrasion resistant coating materials prepared by the sol-gel approach: I. Coatings based on functionalized aliphatic diols and diethylenetriamine

The synthesis of inorganic organic hybrid materials has been undertaken and used as abrasion resistant coatings for polymeric substrates by the sol-gel method. The organic components are diethylenetriamine (DETA), glycerol, and a series of aliphatic diols which are functionalized by 3-isocyanatopropyltriethoxysilane. The inorganic components are tetramethoxysilane (TMOS), aluminum tri-see-butoxide, titaniumsec-butoxide and zirconiumn-propoxide. Solutions of these materials are spin coated onto bisphenol-A polycarbonate sheet and thermally cured to obtain a transparent coating of a few microns in thickness. Following the curing, the abrasion resistance is measured and compared with a control having no coating. It was found that the abrasion resistance of inorganic organic hybrid coatings in the neat form or containing additional silicon, titanium, zirconium, and aluminum alkoxides can be very effective to improve abrasion resistance. The adhesion tests show that the adhesion between coating and substrate can be greatly improved by treating the polymeric substrate surface with an oxygen plasma or a primer solution of isopropanol containing 3-aminopropyltriethoxysilane. Other experiments, such as the abrasion resistance tests following conditioning in a hot-wet condition (boiling water treatment), microhardness tests. UV absorption behavior, and the observation of abraded surfaces, were also undertaken in order to evaluate these coating materials.     

Viscoelastic properties of alkyd ceramers

The viscoelastic behavior of three alkyd ceramers was studied using dynamic mechanical thermal analysis (DMTA). A commercial product was compared to model alkyds. The model alkyds were prepared from phthalic anhydride, glycerol, and linseed or sunflower seed oil. Three sol–gel precursors, titanium tetra-i-propoxide, titanium di-i-propoxide diacetylacetonate, and zirconium tera-n-propoxide were investigated. The alkyd ceramers were evaluated as a function of both alkyd type and a sol–gel precursor content. The viscoelastic data showed that both E′ and T_g were affected by sol–gel precursor content. Both the crosslink density and T_g demonstrated a minimum at low sol–gel precursor contents. After this minimum, both the crosslink density and the T_g increased substantially. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2017–2028, 1999     

新型硅溶胶改性环氧复合涂料的制备及性能分析

通过溶胶-凝胶法制备氨基改性硅溶胶,并将其掺混改性E-44环氧树脂以得到硅溶胶改性环氧复合涂料。利用红外光谱(FT-IR)、接触角、热重(TGA)等对所得涂层进行分析测试。结果表明:当加入的改性S iO2硅溶胶占环氧树脂含量为2%~5%时,涂层的附着力、硬度、耐冲击性、柔韧性等较好,同时涂层的耐酸、耐碱、耐汽油、耐蒸馏水、耐盐水效果也达到实际使用标准。杂化涂层中S iO2与环氧树脂两相间存在化学键及氢键作用,有机-无机杂化交联的结果,可提高涂层的耐高温及防腐蚀性能。     

Organic–inorganic coatings based on epoxidized castor oil with APTES/TIP and TEOS/TIP

Two series of organic–inorganic hybrid films were prepared from epoxidized castor oil (ECO) and the inorganic precursor titanium(IV) isopropoxide (TIP), combined with silicon precursors, either 3-aminopropyltriethoxysilane (APTES) or tetraethoxysilane (TEOS) with different organic to inorganic proportions. Films were pre-cured at room temperature under an inert atmosphere and subsequently submitted to thermal curing. The macro- and microscopic properties of the films, including adhesion, hardness, microstructure (SEM) and thermal properties, were determined as a function of the proportion of ECO to inorganic precursors. Morphological studies showed that the hybrid films were microscopically homogeneous. The addition of TIP decreases substantially the curing time. The hardness and tensile strength of the films increased with increased concentration of inorganic precursor. The combination of the silicon-rich inorganic precursors with TIP improved substantially the mechanical strength of the films. All of the films exhibited good adhesion to the aluminum surface. Aluminum coated with the films and submitted to intensive corrosion test presented excellent protection.     

Organic–inorganic hybrid coatings prepared from glycidyl carbamate resin, 3-aminopropyl trimethoxy silane and tetraethoxyorthosilicate

Hybrid sol–gel coatings were formulated from glycidyl carbamate (GC) resins, 3-aminopropyltrimethoxy silane (APTMS) and tetraethoxyorthosilicate (TEOS) as the inorganic network former. GC and silane-modified GC resins were synthesized and then characterized using Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance Spectrometry (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). The resins were crosslinked with amine crosslinkers such as p-aminocyclohexyl methane (PACM), Ancamide 2050, Ancamide 2353 and Epikure 3164 at 1:1 equivalent ratio of the epoxy groups in the synthesized resin and amine crosslinker. The TEOS content in the coatings were varied to understand its effect on the coating properties. The hybrid coatings were cured at room temperature and humidity for more than 20 days as well as oven cured at 80 °C for 1 h. The thermal properties of the post-cured hybrid materials were evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical property evaluation such as König pendulum hardness measurement, impact resistance and crosshatch adhesion tests of the post-cured samples were carried out. MEK double rub resistance and water contact angle of the coatings were also evaluated. All of the coatings had good adhesion to aluminum 2024-T3 and had good MEK double rub resistance, indicating good crosslinking. Properties such as T_g, hardness and flexibility varied with the amine crosslinker used with Epikure 3164 yielding the lowest T_g, highest flexibility, and lower hardness coatings. Increasing the amount of TEOS modification in the formulations increased the hardness, the T_g, and the thermal stability. The flexibility – determined using reverse impact measurements – also increased with increasing TEOS content.     

Preparation of novel CNSL‐based urethane polyol via nonisocyanate route: Curing with melamine‐formaldehyde resin and structure–property relationship

In this study, we report preparation of a novel cashew nut shell liquid (CNSL)‐based polyol bearing urethane groups. The urethane group in the polyol was induced via isocyanate free route from the reaction of cyclic carbonate with primary amine. The polyol was characterized by determination of hydroxyl number, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and so forth. The polyol was then used as coating component and cured with hexamethoxy methylene melamine (HMMM). Another CNSL‐based polyol without urethane moiety from our earlier reported work was used for preparation of coating for comparative study to determine the effect of urethane group on the coating properties. The coating formulations based on these two polyols were cured with variable amounts of HMMM hardener to optimize coating properties. All the coatings were evaluated for mechanical properties such as adhesion, flexibility, pencil and scratch hardness, impact resistance, pull‐off, and adhesion. The optimized coatings were also evaluated for chemical and thermal properties. It was observed that the urethane containing polyol resulted in better adhesion to the metal substrate at higher quantity of HMMM hardener compared to the other polyol providing significant improvement in various coating properties. The final coating properties were also compared with the acrylic polyurethane coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41391.     

High bio-based content waterborne UV-curable coatings with excellent adhesion and flexibility

A series of bio-based unsaturated polyesters was synthesized by melt polycondensation of itaconic acid with 1,4-butanediol and glycerol. Their chemical structures were confirmed by FT-IR, ¹H NMR, acid and hydroxyl values. Waterborne UV curable dispersion coatings based on these polyesters and acrylated epoxidized soybean oil (AESO) were formulated. The average particle size and their stability before curing as well as the coating properties after curing, including adhesion, flexibility, pencil hardness and solvent resistance, were investigated. Results demonstrated that the glycerol segment in the polyesters together with AESO led to the excellent coating properties in terms of highest grade of adhesion (5B), 0T flexibility, pencil hardness of 5H and excellent solvent resistance (no appearance change after 250 double rubs with ethanol and acetone). This work provided us the coating systems combining the merits of being bio-based, UV-curable and water dispersible.     

Comparison of Titanium‐Oxo‐Clusters Derived from Sol‐Gel Precursors with TiO2 Nanoparticles in Drying Oil Based Ceramer Coatings

Hybrid coatings (inorganic‐organic) were prepared using a blown and epoxidized soybean oil as the organic matrix. Both TiO₂ particles and titanium sol‐gel precursors (Titanium tetra‐i‐propoxide, TIP; titanium (di‐i‐propoxide) bis(acetylactonate), TIA) were incorporated into the coating. Three sizes of TiO₂ particles ranging from 32 nm to 500 nm were used for comparison with the metal‐oxo‐clusters. General mechanical coating properties, tensile properties, and viscoelastic properties of the sol‐gel (ceramer) system were evaluated for the coatings, and the sol‐gel derived metal‐oxo‐clusters were found to have higher tensile modulus, storage modulus (E ′), and T_g compared with the TiO₂ particles.     

Preparation and characterization of photopolymerizable organic–inorganic hybrid materials by the sol-gel method

A series of UV-curable organic–inorganic hybrid materials were prepared by the sol-gel technique and coated onto Plexiglass^® substrate. The effects of the content of EGDMA and the content of the inorganic part on various properties of the coatings, such as tensile strength, hardness, gloss, and cross-cut adhesion, were investigated. It was found that the properties of the coating were improved by the addition of an inorganic part. The thermal properties of the hybrids were enhanced by incorporating silane sol into the organic part. Furthermore, it was found that the coating containing silica had a higher char content at 800 °C than the coating without silica. SEM studies indicated that nanosized (about 50 nm) silica particles were evenly dispersed throughout the organic matrix. A photo-DSC investigation showed that the organic coating polymerized more quickly than the hybrid coating.     

Synthesis and characterization of flame retardant hyperbranched polyurethanes for nano-composite and nano-coating applications

Flame retardant hyperbranched polyurethanes were prepared by reacting phosphorous containing triol, tris(bisphenol-A) mono phosphate, castor oil, and polyethylene glycol with different diisocyanates like TDI, IPDI and HMDI via A₂+B₃ method. In this method A₂ reactants were diisocyanates along with castor oil and polyethylene glycol whereas phosphorous containing triol was used as B₃ reactant and dibutyltin dilaurate (DBTDL) was used as catalyst. Synthesized polyurethans were characterized by gel-permeation chromatography (GPC), elemental analysis, Fourier transform infrared spectroscopy (FTIR) and ¹H NMR spectroscopic techniques. Neat polyurethanes were used for preparing films. Nano-clay composites were prepared with various concentration of organomodified montmorillionite nano-clay. Flame retardant, Thermal and mechanical properties of these hyperbranched polyurethanes and their nano-composites were found out. The polyurethanes and their formulations with nano-clay were also used for the coating of mild steel panels. Scratch, pencil, and impact hardness, flexibility and adhesion properties of coated panels were also determined. Observations show an increase in the scratch hardness and flexibility with the introduction of clay. All the coatings show excellent chemical resistance properties compare to their linear counterpart.     

Novel high‐solids pigmented coatings prepared from a new‐synthesized isophthalate‐based oligoester,a melamine resin,and various fillers

A new‐synthesized hydroxyl‐terminated isophthalate‐based liquid oligoester (L‐311), an hexakis(methoxymethylol)melamine resin, and various inert pigments (fillers) such as either kaolins (Al₂O₃ · 2SiO₂ · 2H₂O) of different particle sizes (1.50 and 4.80 μm) or calcium metalsilicate (CaSiO₃) were used to prepare high‐solids pigmented coatings (PA and PW series, respectively). The physical, chemical, and mechanical properties (pencil hardness, Knoop hardness, flexibility, impact resistance, adhesion, gloss, solvent, and mar resistance) of the new‐formulated pigmented coatings were correlated to the chemical species of the filler, the filler's load and particle size, the quantity of the crosslinker, and the introduction of large particle size colloidal silica into the coating. For measuring the mar resistance of the pigmented coatings, the Taber abrasion method was applied and the inverse wear index, F [=I^?1, cycles/cg (wear index l, weight loss (cg) per number of cycles)], was directly related to the mar resistance. Either when kaolins or calcium metalsilicates were used as fillers, the Knoop hardness, the impact, and mar resistance of the films were affected from the filler's load, whereas the quantity of melamine resin (crosslinker) affected the knoop hardness, the gloss, and the mar resistance. The fillers' particle size and the introduction of large particle colloidal silica affected mainly the mar resistance and the gloss, respectively. The pencil hardness of the PW‐pigmented coatings series (F‐2H) was higher than that of the PA‐series (B‐HB). The chemical composition of the inert pigment proved to be a very important parameter in the preparation of pigmented coatings with specific properties that aim to meet modern and particular demands for various end‐up uses. All the new‐formulated high‐solids (nonvolatiles by weight ～ 70%) pigmented coatings (PA and PW series) presented excellent adhesion (5B), flexibility (> 32%), methyl ethyl ketone (MEK) resistance (>200 rubs), high pencil hardness, good knoop hardness, and very good impact resistance (from 100 up to 160 in.‐lb), independently of the species of the filler (kaolins or calcium metalsilicate). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 576–590, 2002; DOI 10.1002/app.10309     

氟硅改性无溶剂环氧涂料的制备与性能

采用甲基丙烯酸十三氟辛酯（TFM）改性氨基硅油（AS）制备氟化氨基硅油（FAS）,并用其改性环氧树脂（EP）探究氨基硅油及氟化氨基硅油添加量对环氧涂层性能的影响。本文通过红外光谱对改性结果进行表征,通过柔韧性测试、画圈附着力测试、铅笔硬度测试、耐冲击测试、热失重测试、接触角测试、紫外加速老化实验和Tafel极化曲线测试,分别评价涂层的柔韧性、附着力、硬度、耐冲击性、耐热性、疏水性、耐候性和防腐性能,通过扫描电镜对涂层断面进行分析,并通过EDS对涂层进行表面元素分析。结果表明,氟添加量为15%制备氟化氨基硅油改性环氧树脂时,氟硅改性EP涂层相对于未改性EP涂层,硬度由2H提升至3H,附着力由2级提升至1级,柔韧性由1mm提升至0.5mm,耐冲击由45cm提升至50cm,热稳定性增强,接触角由70.5°提升至123°,耐紫外老化（432h）由3级提升至1级,E_corr由-0.6187V正移至-0.1720V,I_corr由1.9858×10^-8A/cm²减小至3.7125×10^-10A/cm²。适量氟化氨基硅油的引入,显著提升了环氧涂层的机械性能、耐候性能和防腐性能。     

Preparation and characterization of sol–gel derived UV-curable organo-silica–titania hybrid coatings

In this work, UV-curable organic–inorganic hybrid coatings based on cycloaliphatic epoxyacrylate were prepared by sol–gel technique. Acid catalyzed solutions of tetraethylorthosilane (TEOS) containing Ti:acac complex were used as an inorganic precursors. UV-curable, transparent hybrid coating materials were applied on plexiglass substrates and their coating performance was investigated by the analyses of various tests such as hardness, gloss, cross-cut adhesion tests, stress–strain test and optical transmission. The mechanical measurements showed that, the tensile properties of coatings underwent an abrupt change from a brittle to a tough material when the inorganic part was incorporated into the cycloaliphatic epoxy acrylate based organic network. UV–vis transmission spectroscopy results indicated that the hybrid materials with high titanium content have good transparences. The thermal behaviour of the coatings was also evaluated. It is observed that the thermal stability of the hybrids is enhanced with incorporation of sol–gel precursor.     

Preparation and characterization of nanostructured biohybrid

Recently, biohybrid materials have gained considerable interests worldwide. They consist of bioresource based derivative as organic matrix in combination with inorganic components with synergistic properties of both such as environment friendliness, biodegradability, flexibility of the former coupled with hardness, UV radiation stability, thermal stability and solvent resistance of the latter. In the present work, we have prepared DGEBA/Castor oil nanostructured biohybrid with a metal alkoxide as inorganic precursor for reinforcement of the matrix. The structure, morphology, thermal behavior and coating properties of the prepared biohybrid have been studied. Our studies revealed that the said biohybrid can be safely employed up to 180 °C as nanostructured protective coating.     

Ceramer coatings from castor oil or epoxidized castor oil and tetraethoxysilane

New inorganic-organic hybrids were synthesized through the reaction of castor oil (CO) or epoxidized castor oil (ECO) with tetraethoxysilane (TEOS). The mass proportions of ECO/TEOS varied from 90∶10 to 60∶40, and films of the material were thermally cured. An IR spectroscopy analysis was performed, and macro- and microscopic properties such as adhesion, hardness, swelling in toluene, microstructure (scanning electron microscopy), and T _g were investigated as a function of the proportion of their inorganic-organic precursor. Morphologic studies showed that the hybrid films were homogeneous when lower proportions of the inorganic precursors were used. Hardness and tensile strength increased with TEOS concentration, whereas swelling in toluene decreased with TEOS concentration. Good adhesion was observed throughout the hybrid series.     

Synthesis of bio-based unsaturated polyester resins and their application in waterborne UV-curable coatings

In this paper, three bio-based unsaturated polyesters were synthesized from itaconic acid and different diols which could be derived from renewable resources. Their chemical structures were confirmed by FT-IR, ¹H NMR and acid value as well as hydroxyl value. Waterborne UV curable networks based on these polyesters were manufactured and their mechanical properties, thermal stability and coating properties including pencil hardness, flexibility, adhesion, water resistance and solvent resistance were investigated. Results showed that the UV-cured polyester coatings exhibited high hardness, good water resistance and solvent resistance. The coatings reported in this paper combined the merits of bio-based materials, UV-curing process and water distribution.     

UV-Absorption and Silica/Titania Colloids Using a Core–Shell Approach

Metal-oxo-colloids have been prepared using tetraethoxysilane (TEOS) oligomers with titanium tetra-i-propoxide (TIP) or titanium (di-i-propoxide) bis(acetylacetonate) (TIA) precursors. Transmission electron microscopy (TEM), FTIR, UV-Vis, and photoluminescence spectroscopy were used to investigate the composition, the size, and optical properties of the Si/Ti core–shell colloids. The presence of hetero-bonded silicate structure (Si–O–Ti) was indicated by FTIR spectroscopy. The size of Si/TIP system ranged from 55 to 120 nm and Si/TIA system ranged from 220 to 250 nm. The TEM data indicated that the size of colloids can be controlled by the TIP or TIA content. The Si/Ti system exhibited strong absorption in the UV-range, yet had excellent optical transmittance in the visible range. The Si/Ti systems exhibited a photoluminescence emission at 329 nm.