Epoxy from high molecular weight

Water-Borne Coatings Prepared from High Molecular Weight Epoxy Resins... 

Propenylphenoxy compounds have attracted much research. BMI—propenylphenoxy copolymer properties can be tailored through modification of the backbone chemistry of the propenylphenoxy comonomer. Epoxy resins may react with propenylphenol (47,48) to provide functionalized epoxies that may be low or high molecular weight, Hquid or soHd, depending on the epoxy resin employed. Bis[3-(2-propenylphenoxy)phthalimides] have been synthesized from bis(3-rutrophthalimides) and o-propenylphenol sodium involving a nucleophilic nitro displacement reaction (49). They copolymerize with bismaleimide via Diels-Alder and provide temperature-resistant networks. 

Assuming maximum corrosion resistance is required, then an anticorrosive primer will be needed, with best protection coming from a crosslinked epoxy stoving primer. Most other properties are dominated by the finish, which will be based on a high molecular weight-polymer, either linear or (more usually) crosslinked. The precise selection of the polymer depends on the balance of properties required, but will be constrained by the type and rate of curing necessary. 

Table 13.6 shows the characteristics and properties of supported and nonsupported high-molecular-weight epoxy resins cast from solvent solution. A crosslinked and uncrosslinked formulation using the same high-molecular-weight epoxy is shown for comparison. 

For instance an epoxy-functionalized polyester from the suberin monomer cis-9,10-epoxy-18-hydroxyoctadecanoic acid (see also Chapter 1) was synthesized by Olsson et al. [30]. The lipase-catalyzed polymerization was performed in toluene in the presence of 4A molecular sieves for 68 h and high molecular weight of epoxy-functionalized polyester was obtained (M , =20000 M JMn =2.2). 

High molecular weight liquid epoxy resins from modified vegetable oils such as epoxidised soybean, rapeseed, linseed and sunflower oils, as well as from hydroxylated soybean and rapeseed oils have also been prepared. Reactions of (i) epoxidised oils, with bisphenol-A and (ii) bisphenol-A-based epoxy resin with hydroxylated natural oils in the presence of different catalysts such as LiCl, 2-methylimidazole, triphenylphosphine and triethanolamine at 130-160 C (depending on the catalyst type) under nitrogen, produce the required epoxy resins as shown in Rg. 7.7. ... 

P. Czub, Synthesis of high-molecular-weight epoxy resins from modified natural oils and bisphenol A or bisphenol A-based epoxy resins , Polym Adv Technol, 2009,20,194-208. 

Natural and synthetic rubber and synthetic resins are soluble in organic solvents resulting in cements, resin solutions, or lacquers. In addition, there are many cellulose derivatives, such as nitrocellulose, ethyl cellulose, and cellulose acetate butyrate, used in preparing solvent-based adhesives. Solvent-hased adhesives are also prepared from cyclized rubber, polyamide, and polyisobutylene. Low-molecular-weight polyurethane and epoxy compounds can be used with or without solvent. On the other hand, high-molecular-weight types or prepolymers require solvent to make application possible. 

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