Synthesis and characterization of phenol–formaldehyde microcapsules containing linseed oil and its use in epoxy for self‐healing and anticorrosive coating

Phenol–formaldehyde microcapsules with linseed oil as an active agent were produced by applying in situ polymerization method. The anticorrosion and self‐healing efficiency of the synthesized materials were studied. Characteristics of these synthesized capsules were studied by Fourier transform infrared spectroscopy, and surface morphology was analyzed by using scanning electron microscope. Controllable particle size was estimated at different rpm of stirrer and particle size was checked under microscope and also by using particle size analyzer. The anticorrosion performance of encapsulated microcapsules coated with epoxy resin was carried out in 5% NaCl aqueous solution. The effectiveness of linseed oil filled microcapsules was investigated for healing the cracks generated in paint films or coatings. It was found that the cracks were successfully healed when linseed oil was released from ruptured microcapsules. Further, linseed oil‐healed area was found to prevent effectively the corrosion of the substrate in immersion studies. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Smart coating for corrosion protection by adopting nano particles

Nano containers with a shell possessing controlled release properties can be used to fabricate a new family of active coatings that can respond quickly to change the environment/integrity of the coatings. The release of corrosion inhibitors encapsulated within nano containers can prevent further corrosion. The structural evolutions and morphological characteristics of nano particles are investigated using XRD, SEM, FT-IR and AFM. The author reports an in situ encapsulation method demonstrating over an order of magnitude size reduction for the preparation of urea-formaldehyde capsules filled with a healing agent, linseed oil and corrosion inhibitors. Capsules with diameters as small as 30–40 μm are achieved using stirring techniques. Cracks in paint film were successfully healed when linseed oil and nanoparticles was released from microcapsules ruptured under stimulated mechanical action. Further linseed oil healed area was found to prevent corrosion of the substrate.     

Self-lubricating epoxy composite coating with linseed oil microcapsule self-healing functionality

Cured epoxy resins have poor abrasion resistance, which shortens the service life of the material. This work aims to improve the tribological properties of epoxy resins by coupling self-lubrication and auto-healing. In this study, linseed oil microcapsules with an average particle size of 38.57 μm and good thermal stability were successfully prepared by in situ polymerization. The effects of microcapsule content on the tribological, mechanical, and self-healing properties of the composite coatings were studied. It was demonstrated that the composite coating has outstanding self-lubricating properties. The coefficient of friction reduced from 0.634 (pure epoxy resin) to 0.0459 (epoxy resin with 10 wt.% linseed oil microcapsules). Wear rate reduced from 7.16 × 10⁻⁴ mm³/(N m) to 1.74 × 10⁻⁵ mm³/(N m). The self-lubricating mechanism of the coating was investigated by SEM and EDS, which indicated that the formation of uniform and continuous lubricating film on the surface of the friction pairs was the key to improving the wear resistance of the material. In addition, the linseed oil released after the microcapsules rupture can repair the abrasion marks by reacting with oxygen during the friction process. The dual-functional effect of linseed oil microcapsules prolongs the life of epoxy resin coating and expands its application range.     

Preparation and Characterization of Microcapsules Containing Soybean Oil and Their Application in Self-Healing Anticorrosive Coatings

Synthetic self-healing materials are a new prototype in polymeric coatings. In the present investigation, soybean oil along with drier was encapsulated in urea–formaldehyde (UF) microcapsules, which were successfully prepared by in situ polymerization and their self-healing ability, the corrosion resistance, gloss, and adhesion strength of microcapsules were studied. The synthesized microcapsules were characterized by Fourier transform infrared spectrometer for identification of separated core and shell materials and their surface morphology was studied by scanning electron microscope. The particle size was checked under optical microscope and confirmed with particle size analyzer. Effectiveness of soybean oil-filled microcapsules was investigated for healing of cracks generated in anticorrosive coatings. Cracks in paint coatings were found to be healed when soybean oil was released from microcapsules under simulated mechanical action and the corrosion resistance of healed area was evaluated by immersion study.     

Tung oil: An autonomous repairing agent for self-healing epoxy coatings

The capability of the encapsulated Tung oil was investigated as a scratch healing agent for self-healing coatings. Encapsulation of Tung oil with urea–formaldehyde shell was carried out by in situ polymerization. Before the mechanical agitation of microcapsules into epoxy resin, their characteristics were evaluated by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Released Tung oil from ruptured microcapsules healed the artificial scratch in the coating matrix successfully. Corrosion resistance of healed area was evaluated by electrochemical impedance spectroscopy (EIS) and immersion test; and the results were compared with neat epoxy coating.     

二环戊二烯双酚型环氧树脂及环氧酯漆的合成研究

本文用二环戊二烯和苯酚合成二环戊二烯双酚,再用它与环氧氯丙烷合成二环戊二烯双酚型环氧树脂,并用这种环氧树脂与亚麻油酸合成气干型环氧酯漆,测试了漆膜的性能。实验证明,适当的酚超量和较低的滴加二环戊二烯的反应温度可控制二环戊二烯的自聚反应。     

二环戊二烯—苯酚树脂的合成及其在油性漆中的应用

在三氟化硼催化剂存在下，采用二环戊二烯和苯酚合成了二环戊二烯－苯酚树脂，并用此树脂和亚麻油配制成油性漆。列举了漆膜的各项性能指标。讨论了不同摩尔比二环戊二烯和苯酚，以及反应温度对树脂的软化点和游离酚含量的影响。试验表明，热塑性二环戊二烯－苯酚树脂可作为涂料用树脂，在一定程度上可改善漆膜的气干性。     

高固体分自干型苯乙烯改性醇酸树脂

选用蓖麻油、豆油或亚麻油、多元醇、多元酸、苯乙烯及助剂合成了一种高固体分（７０％）、低苯乙烯游离单体量（≤０７质量％）的改性醇酸树脂。该树脂及其涂料性能相当于或优于同类进口树脂     

Application of EIS and EN techniques to investigate the self-healing ability of coatings based on microcapsules filled with linseed oil and CeO2 nanoparticles

Microcapsules with urea–formaldehyde as the shell and linseed oil as the healing agent were synthesized by a previously reported procedure. Two kinds of synthesized microcapsules, without and with CeO₂ nanoparticles, were separately added to the epoxy resin coatings. The epoxy coatings containing microcapsules were applied on carbon steel, and their self-healing effect was investigated in 0.5 M HCl solution. The amount of the released healing agent that filled up the scratch was estimated by scratch filling efficiency (SFE). The SFE values are only the theoretical estimates of the self-healing performance. The scratch sealing efficiency (SSE), which is a measure of corrosion protection performance of the damaged coating, can be measured by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. For sake of an optimum self-healing system, two series of coatings, with and without nanoparticles, were prepared by using different microcapsule concentrations: 5, 10, 15 and 20 wt%. For comparison, a coating without microcapsules was also prepared. The coated samples with 5% microcapsule concentration, due to the low amount of released linseed oil, could not properly repair the artificial scratch. In contrast, when the microcapsule concentration was equal to or higher than 10% the volume of the released linseed oil was enough to seal the scratch. However, the coating sample containing 15% nanoparticle-loaded microcapsules was the optimum self-healing coating because it showed comparable SSE values to those of samples containing 20% microcapsule concentration in spite of its lower microcapsule concentration. The EN method was employed as a complementary quantitative technique to study the self-healing behavior of coatings. The calculation of the amount of noise charges using the standard deviation of partial signal (SDPS) plots arising from wavelet analysis made it possible to obtain the SSE values of the coatings. The good agreement between EIS and EN results indicates that the EN technique, as well as the EIS method, can be used successfully for the self-healing evaluation.     

Potential for fungal dyes as colorants in oil and acrylic paints

Potential applications for colorants derived from the spalting fungi Chlorociboria aeruginascens, Chlorociboria aeruginosa, Scytalidium cuboideum, and Scytalidium ganodermophthorum are of growing interest across a variety of fields, from wood and textile dyes, to solar cells. Previous research found that these dyes could be carried in natural oils, specifically raw linseed oil, instead of organic solvents, thereby eliminating the toxicity issues surrounding such carriers. In this work, dyes from the aforementioned fungi were extracted, carried in raw linseed oil, and mixed with a range of oil and acrylic paints to determine if the oil carrier was appropriate for delivering the dyes into a paint matrix. The oil-based dyes did not mix evenly with the acrylic paints; however, the acrylic paints maintained the color of the dyes. In contrast, the oil-based paints mixed well with the dyes, but the dyes decolorized (completely lost color) due to the presence of refined linseed oil in the paint base. Artists’ paints do not appear to be compatible with fungal dyes when carried in oil; however, there are still many potential applications for the oil-based dyes, such as wood and textile dyeing.     

Stoving paint from Mesua ferrea L. seed oil based short oil polyester and MF resins blend

A short oil polyester resin based on Mesua ferrea L. (Nahar) seed oil was prepared by the conventional alcoholysis process with glycerol followed by polycondensation with phthalic anhydride using the azeotropic distillation technique. The extent of reaction (P) and average degree of polymerization (DP) with respect to the acid value were determined for this resinification reaction. This resin and a castor oil based similar type of resin were utilized for the preparation of stoving paints separately along with partially butylated melamine-formaldehyde (MF) resin (70:30 weight ratio) using an industrial Ball Mill system. The morphology and thermal stability of paints were studied by scanning electron microscope (SEM) and thermogravimetric (TG) analysis. The performance characteristics of both paints were investigated by measurement of gloss, flexibility, impact resistance, pencil hardness, adhesion, humidity and salt spray tests, etc. The results indicate that the paint based on Nahar oil polyester resin could be used in different applications as low cost stoving paint.     

Emulsifiers derived from linseed oil and their potential use in coatings

In the development of a stable linseed oil emulsion paint, a series of emulsifiers were prepared from linseed, oil and its fatty acids and alcohols: (a) linseed monoglycerides, (b) mono-and dilinseed fatty sorbitan esters and a mixed ester obtained by the transesterification of linseed oil with sorbitol, (c) polyoxyethylene ether adducts formed by reacting, ethylene oxide with these sorbitan esters, and (d) linseed polyoxyethylene ether made by ethoxylation of linseed alcohols. Another series of surfactants was prepared by esterifying a polyoxyethylene ether of sorbitol with various amounts of linseed fatty acids. Conditions of preparation and pertinent physical, and chemical properties of the emulsifiers are given. Some of these emulsifiers demonstrated filmforming properties. Combinations were formulated into linseed oil emulsion paints with and without zinc oxide. Paints containing zinc oxide have been relatively stable in viscosity for about 2 yr.     

Synthesis of oil based hyperbranched resins and their modification with melamine-formaldehyde resin

In this research hyperbranched resins containing fatty acid residues were synthesized. Dipentaerythritol which has six hydroxyl groups was used as the core molecule, and it was transesterified with (i) castor oil, and (ii) a mixture of castor oil and linseed oil at 240 °C. The resulting molecule had hydroxyl containing ricinoleic acid residue coming from castor oil. It was then esterified with dimethylol propionic acid at 140 °C in the presence of para-toluene sulfonic acid used as catalyst. The hyperbranched resin thus produced was then mixed with melamine-formaldehyde resin to improve its properties. The resins were characterized by FTIR spectroscopy, and the thermal properties were determined by DSC. The resins were thermally stable up to 316 °C. The viscosity of the resin that was synthesized by using only castor oil was 3.0 Pa s, while the one synthesized by using 50% linseed oil had a viscosity of 1.0 Pa s. When reacted with dimethylol propionic acid the viscosity of the former resin increased to 7.0 Pa s, and that of the second to 3.7 Pa s. The hyperbranched resins showed excellent adhesion, gloss, flexibility, and formability. The mixed resin (i.e. hyperbranched and melamine-formaldehyde) had higher hardness values but lower gloss, adhesion, and bending resistance. Both types of resins also had good impact and abrasion resistances.     

Cd and Zn-incorporated polyesteramide coating materials from seed oil—A renewable resource

Cd and Zn metal (with completely filled ‘d’ orbital) incorporated linseed oil polyesteramides [Zn-LPEA and Cd-LPEA] were synthesized by in situ condensation polymerization reaction between linseed fattyamide diol (HELA), phthalic anhydride and divalent cadmium/zinc acetate (different mole ratios) obviating the use of any solvent. The structures of these resins were confirmed by FT-IR, ¹H NMR and ¹³C NMR spectral studies. The solubility of the resin was checked in different polar and non-polar solvents. The physico-chemical and physico-mechanical properties were studied by standard methods. Curing and thermal behavior were investigated by DSC and TGA techniques. The corrosion protective performance of coatings on mild steel strips was investigated by standard methods. Agar diffusion method was used to determine the antibacterial activities of these polymers. The studies revealed that the minor incorporation of divalent cadmium and zinc in virgin linseed oil based polyesteramide [LPEA] enhances the physico-mechanical and anticorrosive properties as well as reduces the curing temperature. Besides these properties they also show effective antibacterial behaviour against the Escherichia coli and Staphylococcus aureus. The Zn-LPEA and Cd-LPEA resins are, therefore, inexpensive coatings material, developed from renewable resource, for anti-corrosive and antibacterial applications.     

Corrosion aspects of alkyd paints modified with linseed and soy oils

The anticorrosive performance of medium-long (54-59%) alkyd paints modified with linseed and soy oils was compared by accelerated tests (Prohesion Cycle) and natural exposition in marine and industrial atmospheres. Differences on the protection mechanism of anticorrosive pigments due to substitution of linseed oil by soy oil were investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Complementary tests such as water vapor and ions permeability in freestanding films were also performed. Results suggested that the type of oil influenced the barrier properties of the paint pigmented with zinc phosphate. The same tendency was verified by resistance values obtained from impedance diagrams. Polarization curves suggest that the action of the pigments in the alkyd paintings is practically the same for both oils. The substitution of linseed oil by soy oil did not impair the anticorrosive performance of alkyd paints and from the economic point of view this substitution could be very interesting.     

Studies on zinc-containing linseed oil based polyesteramide

For the first time the synthesis of zinc containing linseed oil based polyesteramide resins (Zn-LPEA-1 to Zn-LPERA-5) with different loadings of zinc acetate were carried out by in situ condensation polymerization reaction between linseed oil derived linseed fattyamide diol (HELA), phthalic anhydride and zinc acetate (divalent metal salt, different mole ratios) in the absence of any solvent. By-products such as water and acetic acid were removed by the application of vacuum technique. This approach was employed to overcome the use of volatile organic solvents [VOCs] during processing and application of the resin, that are ecologically harmful. The structure of the resin was confirmed by FT IR, ¹H NMR and ¹³C NMR spectral studies. Physico-chemical properties were studied by standard methods. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) was used to measure the thermal behaviour of the resin. The antibacterial studies of Zn-LPEA resins were carried out by agar diffusion method. Antibacterial activities of Zn-LPEA were compared with reported virgin linseed polyesteramide (LPEA) and zinc incorporated petroleum based polymers.     

Synthesis and characterization of hyperbranched and air drying fatty acid based resins

In this research four hyperbranched resins having fatty acid residues were synthesized. Dipentaerythritol, which was used as the core molecule of the resins, was twice esterified with dimethylol propionic acid. This resin was then esterified with the castor oil fatty acids. The hydroxyl group present in the ricinoleic acid which constitutes almost 87% of the castor oil fatty acids was then reacted with linseed oil fatty acids and benzoic acid. The linseed fatty acids were incorporated into the structure to esterify 0, 15, and 70% of the ricinoleic acid on mole basis. These resins were named as HBR-1, 2, and 3. A fourth resin (e.g. HBR-4) was synthesized by the incorporation of ‘15% linseed fatty acids + 55% benzoic acid’. The chemical characterization of the resins was achieved by FTIR spectroscopy and the thermal properties were determined by DSC. The physical and the mechanical properties of the resins were determined. The hardness value of the resins was measured as 24, 27, 25, and 68 Persoz for HBR-1, 2, 3, and 4, respectively. The viscosity of the resins was measured as 17.3, 9.7, 5.8, and 17.5 Pa·s at a shear rate of 200 s⁻¹. The increase in the amount of the linseed fatty acids increased the hardness, and decreased the viscosity of the resins. All resins showed excellent adhesion, gloss, and flexibility.     

Artificial aging and deterioration of oil‐painted Fabriano paper and cardboard paper supports

Fabriano paper and cardboard are commonly used for oil paintings as paper supports. There are different practices for oil painting. Sometimes, painters paint directly on paper supports. They may also impregnate paper supports with linseed oil before painting to prevent the absorption of the binder from the oil‐based paint by the paper, or they may apply a background (e.g., animal glue and calcium carbonate) on the paper supports and then paint their drawings. The effects of aging by heat or ultraviolet light on the mechanical properties (tensile strength, tensile elongation, and tearing resistance), optical properties (changes in color indices), and pH of Fabriano paper and cardboard painted with the aforementioned practices were studied. In addition, the thermal stability of paper painted with these practices was studied with thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyurethane Dispersions Based on Interesterification Product of Fish and Linseed Oil

Alkyd and styrenated alkyd resins based on fish oil and their interesterifications with linseed oil were synthesized. The various properties of fish oil, such as its iodine value, acid value, saponification value and moisture content were determined. The interesterification product of fish oil and linseed oil can be used to partially replace the commercially available linseed oil alkyd resin. Alkyd resin and styrenated alkyd resin were modified with 2,2 dimethylolpropionic acid to introduce acid functionality and then sequentially reacted with isophorone diisocyanate, neutralized with amine, chain extended with ethylenediamine and dispersed in water to form a polyurethane dispersion. The newly synthesized resins and polyurethane dispersions were studied for coating properties such as scratch hardness, adhesion, flexibility, impact, solvent and chemical resistance. The polyurethane dispersions exhibited superior coating properties to those of their respective alkyds and styrenated alkyds.     

改性蜜胺树脂香精微胶囊的制备研究

为解决日化香精易挥发变质的问题,拓宽其应用领域,采用原位聚合法制备了一系列蜜胺树脂（MF）香精微胶囊。以低甲醚化蜜胺（L-MMF）树脂为例,傅立叶变换红外光谱（FT-IR）的结果证实了微胶囊对香精的良好包覆性,热失重〈TGDTG）分析说明微胶囊大幅提高了香精的耐热性能。进一步采用脲、间苯二酚、聚乙烯醇（PVA）、聚乙二醇（PEG）、氯化钠对蜜胺树脂进行改性并与未改性的树脂及不同甲醚化程度的蜜胺树脂进行对比,研究了改性对微胶囊包覆效果的影响。结果表明,低甲醚化蜜胺树脂和聚乙烯醇改性蜜胺树脂对香精的包覆效果较好,所得香精微胶囊粒径小,分布窄,包覆率高。