Epoxy novolac Synthesis

Epoxy novolacs are s> nthesized by reaction of chloromethyloxirane with novolacs to place a secondary hydroxyl, alkyl ether group on the aromatic ring. The reactions occurring during epoxy novolac synthesis are shown in equations 45-46. These reactions are similar to the synthesis of conventional epoxy resins. 

Use of an chloromethyloxirane excess for epoxy novolac synthesis increases the conversion of t enolic hydros groups to epo groups and minimizes the reaction of phenolic hydroxy groups with epoxy groups that are attached to the novolac molecules. The chloromethyloxirane excess limits bianehing reactions. Thus, equation 46 is usually driven as close to completion as possible since hydrolyzable and nonhydrolyzaHe, oiganically bounded ehlorine reduces the... 

Trisphenol epoxy novolacs, 10 371-372 Tristimulus colorimeters, 7 325 Trisubstituted alkene synthesis, 13 653 Trisubstituted silyl group, in silylation, 22 691... 

Crotonic acid 2-Ethylhexyl chloride 2-Methylpropanal Pyrocatechol Triisobutylene resin synthesis, coatings m-Divinyl benzene resin, automotive components Polyarylether ketone resin resin, blow moldings Ethylene/methyl acrylate copolymer Polyarylether ketone resin resin, coatings Epoxy-novolac resin, coatings UV-curable... 

The epoxy novolac resin was prepared by two step reactions. The first step was involved in the formation of novolac resin through chemical reaction between phenol and formaldehyde in acid environment. In the second step, the epoxidation of previously prepared novolac resin was carried out by reacting epichlorohydrin with a novolac resin in a specific molar ratio. The detail of the synthesis of novolac resin and its epoxidation was described in our previous report [19,20]. The typical properties of the synthesized ENR are given in Table 16.2. 

Rutnakompituk, M. Modification of epoxy-novolac resins with polysiloxane containing nitrile functional groups synthesis and characterization. Eur. Polym. J.. 2005, 41, 1043. 

Fig. 1 The schematics of synthesis of a novolac resin b epoxy novolac resin...

The literature on basic- and acid-catalyzed alkylation of phenol and of its derivatives is wide [1,2], since this class of reactions finds industrial application for the synthesis of several intermediates 2-methylphenol as a monomer for the synthesis of epoxy cresol novolac resin 2,5-dimethylphenol as an intermediate for the synthesis of antiseptics, dyes and antioxidants 2,6-dimethylphenol used for the manufacture of polyphenylenoxide resins, and 2,3,6-trimethylphenol as a starting material for the synthesis of vitamin E. The nature of the products obtained in phenol methylation is affected by the surface characteristics of the catalyst, since catalysts having acid features address the electrophilic substitution in the ortho and para positions with respect to the hydroxy group (steric effects in confined environments may however affect the ortho/para-C-alkylation ratio), while with basic catalysts the ortho positions become the... 

Calculations for a branched advancement synthesis are defined to permit development of well-characterized functionality in the product molecules. In this study, the difunctional epoxy resin monomer used is the diglycidyl ether of bisphenol A, Epon 828, and the multifunctional epoxy phenol novolac resin used is DEN 438. Let ... 

Synthesis Epoxy resins consisting ofglycidyl ether, ester and amines are generally prepared by the condensation reaction between diol, dibasic acid or amine and epichlorohydrin in the presence of sodium hydroxide with the elimination of hydrochloric acid. The commercially available epoxy resins are, however, made by the reaction of epichlorohydrin and bisphenol-A. Cashew nut shell liquid (CNSL)-based novolac epoxy resins have also been reported [342]. 

An outline of the general method of synthesis of epoxy resin and novolac epoxy resin are shown in Schemes 4.9 and 4.10 respectively. 

In most cases, epoxy acrylates do not have any free epoxy groups left from their synthesis but react through their unsaturation. Within this group of oligomers, there are several major subclassifications aromatic difunctional epoxy acrylates, acrylated oil epoxy acrylates, novolac epoxy acrylate, aliphatic epoxy acrylate, and miscellaneous epoxy acrylates. These are described in Chap. 4. 

Pure meto-cresol has been used for manufacture of synthetic musk— musk ambrette, used as a fixative to perfumes, for manufacture of synthetic Thymol and Menthol amd also leather preservative p-chloro-meto-cresol, synthetic pyre-throids, and lastly for manufacture of 2,3,6-trimethylphe-nol—an intermediate for vitamin E. o-Cresol has been used for manufacture of Coumarin and some derivatives which are employed in perfumery as fixative. o-Cresol has also been used for making Novolac and epoxy resins and also for the herbicides based on di-nitro-oAt/io-cresol, etc. In sum, individual cresols have been very successfully converted to important intermediates in the organic chemical synthesis. It is expected that further development work will lead to synthesis of many more organic chemicals of vital importance. While new chemicals using individual cresols are in the pipeline... 

Thermal synthesis of methylene bridged, substituted phenols in the absence of a catalyst occurs in a melt with paraformaldehyde at temperatures between 150-200°C [33]. A representative reaction is 4,4 -(l-methyl ethylidene)bisphenol reacting with paraformaldehyde at 200°C to form novolacs with the structure drawn in equation 12 [33]. The acidity of the phenolic group is probably sufficient to catalyze the formation of these special novolacs, all of which have a yellow color. These products are prepolymers for the synthesis of epoxy resins [63]. 

In this chapter, we will discus the synthesis and investigation of some properties of copolymers produced in result of copolymerization of epoxy-silicon oligomers and novolac phenol-formaldehyde oligomers have been carried out. 

Pol)merization reaction of phenol-formaldehyde oligomer (novolac resin - SF-0112) with tetraepoxypolyphenylsilsesquioxanes was carried out in melt condition at 125 5°C temperature at various ratios of initial compounds, without catalyst. The samples were tested on contain of epoxy groups during the reaction. It was shown that during synthesis of block-copolymers the reaction rate decreases, which may be explained by presence of free phenols in used phenol-formaldehyde oligomer. In accor-... 

Chen HT, Gao J, Wang G, Shi SQ, Zhang SB, Cai LP (2004) Effect on temperature on calcium carbonate deposition in situ on bamboo fiber and polymer interfaces. Wood Fiber Sci 46 1-12 Datta C, Basu D, Baneijee AN (2002) Mechanical and dynamical mechanical properties of jute fibers-Novolac-Epoxy composite laminates. J App Polym Sci 85 2800-2807 Garea SA, Nicolescu A, Deleanu C, lovu H (2010) New nanocomposites based on epoxy resins reinforced with modified montmorillonite. Int J Polym Anal Charact 15 497-508 Ghosh P, Mitra PS, Baneijee AN (2003) Photopolymerization of methyl methacrylate with the use of bromine as photoinitiator. J Polym Sci Polym Chem Ed ll(8) 2021-2030 Jia N, Li SM, Ma MG, Sun RC, Zhu L (2011) Green microwave-assisted synthesis of cellulose/ calcium silicate nanocomposites in ionic liquids and recycled ionic liquids. Caibohydr Res 34 2970-2974... 

The effects of solvent exposure on the viscoelastic properties of several vinyl ester resins (phenohc-novolac epoxy, propoxylated bisphenol-A fu-marate, urethane and bisphenol-A epoxy based) and various unsaturated polyester resins (terephthalic or isophthaUc acid with a standard glycol based) containing 10wt% glass fiber were studied [130]. The results of dynamic mechanical analysis showed that the influence of exposure time to the solvent as well as the influence of temperature depended on the styrene content and chemical composition of the studied resins, while the amount of cobalt octoate used for the synthesis as the accelerator had no influence on the viscoelastic properties of the prepared materials after solvent exposure. It was also found that not fully cured urethane vinyl ester and the terephthahc acid-based unsaturated polyester resins showed excellent resistance to sulfuric acid exposure. However, interactions between the tested resins and petroleum could possibly occur through intermolecular bonding between the non-polar chains of the cured resins and the solvent. 

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