Epoxies cyclic aliphatic

Several other epoxy resins have been made. Many contain glycidyl ether group while others are cyclic aliphatic epoxies and acrylic aliphatic epoxies. 

Brominated flame retardants (BFRs) are a structurally diverse group of compounds including aromatics, cyclic aliphatics, phenolic derivatives, ahphatics, and phthahc anhydride derivatives (Figure 31.3). The most common BFRs are tetrabromobisphenol A (TBBPA), polybrominated diphenyl ethers (PBDE), hexabromocyclododecane (HBCD), and polybrominated biphenyls (PBB). The primary use of TBBPA is as reactive additive in epoxy resin circuit boards, while decabromodiphenyloxide (DBDO) is primarily used in high impact polystyrene for electronic enclosures. PBDEs are typically used as the additive type of flame retardant in high impact polystyrene, acrylonitrile butadiene styrene, flexible polyurethane foam, textile coatings, wire and cable insulation and electrical connectors. 

Two types of nonglycidyl ether epoxy resins are commercially available cyclic aliphatic epoxies and acyclic aliphatic epoxies. 

Cyclic aliphatic epoxy resins were first introduced in the United States. Some typical examples of commercial materials are 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexane carboxylate (Unox epoxide 201, liquid) (IX), vinylcyclobexene dioxide (Unox epoxide 206, liquid) (X), and dicyclopentadiene dioxide (Unox epoxide 207, solid) (XI). 

Acyclic aliphatic resins differ from cyclic aliphatic resins in that the basic structure of the molecules in the former is a long chain, whereas the latter, as shown, contains ring structures. Two types of acyclic aliphatic epoxies are commercially available, namely, epoxidized diene polymers and epoxidized oils. 

Bopp RC. U.V. light stabilizer compositions comprising cyclic aliphatic epoxy, UV screener, and polyalkyldipiperidine (HALS) compounds. U.S. Patent 4843116. June 27,... 

With aromatic resins, such as those based on bisphenol-A, cured with aromatic or cyclic aliphatic hardeners, it is difficult to prevent gross phase separation without introducing an adequate level of alkoxysUane functionality in the epoxy resin. Many commercially available silane-coupling agents can be used for this purpose. 

Two types of non-glycidyl ether epoxy resins are commercially available, namely cyclic aliphatic and acyclic aliphatic resins. 

Although the enantioselective intermolecular addition of aliphatic alcohols to meso-epoxides with (salen)metal systems has not been reported, intramolecular asymmetric ring-opening of meso-epoxy alcohols has been demonstrated. By use of monomeric cobalt acetate catalyst 8, several complex cyclic and bicydic products can be accessed in highly enantioenriched form from the readily available meso-epoxy alcohols (Scheme 7.17) [32]. 

Cycloaliphatic Epoxy Resins. This family of aliphatic, low viscosity epoxy resins consists of iwo principal varieties, cyclouleliils epoxidi/.cd with peracetic acid anil diglvcidyl esters of cyclic diearboxvlic acids. 

The configuration of the produced diol is influenced by the relative stabilities of the benzyl- or alkylcarbonium ions formed during the reaction. Similar reactions were investigated earlier. The rate and stereochemistry of the diborane reaction is altered by a small quantity of LiCl. Wide-ranging research has been performed with regard to the mechanism and stereochemistry of the diborane reduction in connection with cyclic and aliphatic a, 3-unsaturated and allylic epoxides, on diterpene models, " and by study of the reduction of epoxy-methylenecyclohexane and 2,3-epoxy-3-methylcyclohexanone. ... 

Nonetheless, for the more than 50 years since the first publication in this field, NIPUs still do not have sufficiently broad application. This can be explained by certain features of these materials. Cyclic carbonate (CC) groups interact with aliphatic and cycloaliphatic polyamines at ambient temperatures more slowly than isocyanates with hydroxyl groups. The rate of this reaction is comparable to the rate of curing epoxy resins (ER) with amines. At the same time, the CCs react only with primary amino groups, in contrast to the ERs, which react with primary and with secondary amino groups. This results in a decrease in cross-linking density of the polymer network. 

A research team led by O. Figovsky synthesized aliphatic multifunctional cyclic carbonates from corresponding epoxies and carbon dioxide and NIPUs based on them [17,18], The authors tested some compositions polyfunctional carbonates synthesized in the laboratory, namely trimethylolpropane tricyclocarbonate (TMPTCC) and chlorine-contained aliphatic tricyclocarbonates (on the base of chlorine-contained aliphatic epoxy resins Oxilin ) and various diamines 2-methylpentam-ethylene diamine (MPMD), Dytek A, Invista Co. meta-xylenediamine (MXDA), Mitsubishi Gas Chem. Co. polyetheramineJeffamineEDR-148, Huntsman Co. and diethylenetriamine (DETA), D.E.H. 20, Dow Chemical Co. The properties of these materials are shown in Table 4.1. 

Polyfunctional aliphatic epoxy resins are generally cycloaliphatic in nature, derived from the corresponding cyclic polyolefins, for instance, (3,4-epoxycyclohexyl)methyl-3,4-epoxycyclohexanecarboxylate (3) from 3-cyclohexenylmethyl-3-cyclohexenecarJboxylate. Aliphatic epoxy resins are much more reactive toward electrophilic (acidic) curatives than are the aromatic resins, but much less reactive toward the more common nucleophilic (basic) curatives. In addition, aliphatic resins give cured products which are more brittle than those obtained from the aromatic resins. 

A wide variety of epoxy resins are commercially available monofunctional or polyfunctional, aliphatic, cyclic, or aromatic. Brominated epoxies may be useful where flammability is a concern. An oxirane functionality is all that is needed to make an epoxy resin, and structural adhesives are only one of over a dozen different uses for epoxy resins. Many epoxy resins on the market will not necessarily be suitable for adhesives, but their availability does expand the choices available for adhesive formulators. The specialty epoxy resins developed specifically for adhesive use sometimes will be more costly than the DGEBPA resins but may provide the basis for a specialty adhesive that can meet a unique need and therefore command a proportionally higher price. Examples of these are epoxy-fimctional dimer acids, urethanes, and various elastomers. 

Another type of epoxy oligomers are the cyclo-aliphatic ones, obtained by oxidation of cyclic diolefins with various peroxidic compounds (organic or inorganic hydroperoxides), hypochlorous acid, halogenhydrines and their derivatives, and oxygen or ozone. At present, the main industrial procedure for their production uses peracetic acid. In keeping with initial cycloolefin structure, diepoxides with different structures are produced, with the peculiarity that peroxidic oxygen is bound to the aliphatic cycle. 

Gabriel Rokicki is a chemistry professor at the Faculty of Chemistry, Warsaw University of Technology, Poland, where he received all his academic education (MSc in 1971, PhD in 1989, and tenure professor in 2002). His current scientific activities include synthesis, stmcture, and properties of polymer materials, such as aliphatic polycarbonates, polyurethanes, epoxy resins, and biodegradable polymers. He has devoted a special interest to the use of functional polymers in obtaining specialty ceramic materials as well as to polymer recycling. Earlier major interests included the utilization of carbon dioxide and cyclic carbonates in the synthesis of condensation polymers. Another topic of interest was polymeric ion-sensors based on modified calixarenes. He is the author and coauthor of 160 scientific papers and holds more than 50 patents in the above-mentioned areas. At the Faculty of Chemistry of Warsaw University of Technology, he conducts lectures on polymer chemistry and technology. 

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