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Effect of Structure of Diphenol on Polymerization of Bis(isoimide)
Published in Didier Rouxel, Sabu Thomas, Nandakumar Kalarikkal, Sajith T. Abdulrahman, Advanced Polymeric Materials, 2022
V. Sarannya, R. Surender, S. Shamim Rishwana, R. Mahalakshmy, C. T. Vijayakumar
Alkyd resins are polyesters used primarily in organic paints, with some molding applications. The alkyd resin is based on acids (phthalic anhydride, maleic anhydride, isophthalic acid, and terephthalic acid) and polyhydric alcohols (glycols, glycerol, pentaerythritol, and sorbitol). These resins are modified by the addition of fatty acids derived from mineral and vegetable oils. Alkyds of the glycerol-phthalic acid type or glycerol-sebacic acid are used in lacquers along with natural resins such as shellac to impart flexibility. Drying alkyds contain, in addition to the glycerol phthalate components, some oils or acids of drying oils. They are used in varnish type coatings. Phenol-aldehyde or urea- or melamine-aldehyde resins may be added to improve hardness, and hard resins are made from maleic anhydride combined with glycerol and rosin. Their function is to improve film hardness and gloss in both lacquer and varnish coatings [1].
Renewable Resource-Based Environmental Friendly Waterborne Polymeric Anticorrosive Nanocomposite Coatings
Published in Neha Kanwar Rawat, Iuliana Stoica, A. K. Haghi, Green Polymer Chemistry and Composites, 2021
Mohd Irfan, Halima Khatoon, Rabia Kouser, Abu Darda, Shahidul Islam Bhat, Sajid Iqbal
WB alkyds (Fig. 7.7) have received a lot of importance in the past few years due to their synthesis via eco-friendly routes. Alkyd resins are defined as polyesters of moderate molecular weight, which are obtained by polymerization of (1) polyalcohols, (2) anhydrides or dicarboxylic acids, and (3) unsaturated long fatty acids chain of triglycerides.33 In general, monoglycerides of fatty acids serve as the precursor molecules for the synthesis of various alkyd resins. In the previous case, alcoholysis of VO with glycerol resulted in the formation of monoglyceride. Then, the hydroxyls of the monoglyceride are transesterified by a polyacid. Alkyd resins obtained by this way have high viscosity, good drying, and hardening properties.
Other Applications of Glycerine
Published in Eric Jungermann, Norman O.V. Sonntag, Glycerine, 2018
In the paint and coatings industry glycerine’s usage has been a major factor. In the manufacture of basic alkyd resins three basic components are used: polyhydric alcohols, dibasic acids, and fatty acids. The dibasic acid is usually phthalic acid, the polyol is glycerine, and the fatty acid is polyunsaturated. Glycerine is the predominant polyhydric alcohol used because the alkyd reactions can be controlled using glycerine. The viscosity of the resins formed are low and find application in latex paints. The application of an alkyd utilizing glycerine is largely determined by its “alkyd ratio” or the proportion of glycerol phthalate in the resin. A high alkyd ratio ordinarily found in commercial products is 65. These resins would be high in viscosity and may require addition of aromatic solvents. The primary use for these alkyds are as hardeners for other alkyds of high oil content. When the alkyd ratio is 50, viscosity is still high and solvents may be required. These resins are used for baked coatings.
Enhancement of anti-corrosion and mechanical properties of alkyd-based protective paints for steel petroleum structures incorporating natural limonite pigment
Published in Cogent Engineering, 2018
M.I. Abdou, Hany El-Sayed Ahmed, M.A. Wahab Gaber, A.M. Fadl
Although many techniques have been developed to reduce or minimize the action of corrosion, the use of paints or anti-corrosion coatings is the most efficient, economical and most widely used system at present for this purpose. Iron oxides occupy a special place as pigments or agents “barrier” in the formulation of anti-corrossive paints (Al-Sabagh, Abdou, Migahed, Abd-Elwanees et al., 2017a; Abdou, Ayad, Diab, Hassan, & Fadl, 2017). The widespread use of iron oxides in the field of anticorrosion paints is because they have a number of attributes that make them ideal candidates for use as protective pigments (Al-Sabagh, Abdou, Migahed, Fadl et al., 2017). Alkyd resins are the most common resins to be used in solvent-based paints. They are basically polyesters and are used for both air-drying and heat-cured paints. Alkyd coating offers benefits of good adhesion, rapid drying, good flexibility, strength and durability at nominal cost; however alkyds cannot endure alkaline conditions (Forsgren, 2006; Fabregat et al., 2012; Soucek & Johansson, 2012). In literature, various researchers have investigated the corrosion resistance of alkyd based coating systems (Ahmed, Abdel-Fatah, & Youssef, 2012; Araujo, Margarit, Mattos, Fragata, & de Lima-Neto, 2010; Bhanvase & Sonawane, 2010; Gonçalves, Baldissera, Rodrigues, Martini, & Ferreira, 2011; Yeganeh & Saremi, 2015). The protective action in alkyd-based coatings was generally achieved with the use of inhibitors such as metallic pigments, metal oxides and salts at different concentrations. Attempts have been carried out to improve the anticorrosion behavior of the organic paints containing some inorganic pigments such as lamellar micaceous iron oxide (MIO) which is essentially a type of hematite, lamellar aluminum and Zn-dust (Arman, Ramezanzadeh, Farghadani, Mehdipour, & Rajabi, 2013; Kakaei et al., 2013a, 2013b; Nikravesh, Ramezanzadeh, Sarabi, & Kasiriha, 2011; Sørensen, Kiil, Dam-Johansen, & Weinell, 2009). The incorporation of nanoferrite (Fe2O3) particles in soya alkyd coating enhanced corrosion resistance and physico-mechanical properties (Rahman & Ahmad, 2014). Modification of alkyd coatings with aluminum oxide (Al2O3) nano-sized pigment improved anticorrosion behavior, UV resistance and mechanical properties (Dhoke & Khanna, 2012; Dhoke, Mangal Sinha, & Khanna, 2009). It has been illustrated that application of ZnO nanoparticles improves the anticorrosion behavior of alkyd based coatings (Dhoke & Khanna, 2009). Egyptian ilmenite ore was utilized after grinding to micro-sized scale as anticorrosive pigment and mechanical property promoter for internal epoxy coating of gas transmission pipelines (Fadl, Al-Sabagh, Abdou, & Migahed, 2016).