Aliphatic glycidyl ether

Aliphatic Glycidyl Ethers. Aliphatic epoxy resins have been synthesized by glycidylation of difunctional or polyfunctional polyols such as a 1,4-butanediol, 2,2-dimethyl-l,3-propanediol (neopentyl glycol), polypropylene glycols, glycerol, trimethylolpropane, and pentaerythritol. 

The epoxidation is generally conducted in two steps (/) the polyol is added to epichlorohydrin in the presence of a Lewis acid catalyst (stannic chloride, boron triduoride) to produce the chlorohydrin intermediate, and (2) the intermediate is dehydrohalogenated with sodium hydroxide to yield the aliphatic glycidyl ether. A prominent side-reaction is the conversion of aliphatic hydroxyl groups (formed by the initial reaction) into chloromethyl groups by epichlorohydrin. The aliphatic glycidyl ether resins are used as flexibilizers for aromatic resins and as reactive diluents to reduce viscosities in resin systems. 

Monofunctional aliphatic glycidyl ethers, eg, based on / -butanol or mixed Cg—alcohols, are used exclusively as reactive diluents to reduce viscosities of epoxy resin systems. Some loss of desirable cured properties results from the lowered functionality of the systems. 

Aliphatic glycidyl ethers, 10 376-377 Aliphatic hydrocarbons. See also Aliphatics photochemical chlorination of, 19 113 separation of, 10 782-785 Aliphatic hydroxyl, replacement with chloride, 13 821... 

Monofunctional, aromatic cresyl-glycidyl ether p-tertiary butylphenyl glycidyl ether Monofunctional, aliphatic ethyl hexyl-glycidyl ether long-chain aliphatic glycidyl ethers... 

Bisphenol A epoxy resin diluted with 15 wt% C12-C14 aliphatic glycidyl ether 3... 

Chem. Descrip. Epichlorohydrin-bisphenol A epoxy with aliphatic glycidyl ether diluent... 

Aliphatic glycidyl ethers Allyl glycidyl ether (AGE) [106-92-3]... 

Monofunctional Glycidyl Ethers and Aliphatic Glycidyl Ethers... 

Because of their low viscosity the liquid cyclic aliphatic resins find use in injection moulding and extrusion techniques, as used for glass-reinforced laminates. They are also very useful diluents for the standard glycidyl ether resins. 

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

However, disappointingly low selectivity was observed with monosubstituted aliphatic epoxides such as 1-epoxyoctane (la, E<5) or benzyl glycidyl ether (le, <2) [51,55]. On the other hand, sterically more demanding 2,2-disubsti-tuted oxiranes (2) turned out to be much better substrates (Scheme 9, Table 2). 

In addition to the DGEB A resins, there are several other types of epoxy resins of commercial significance. The most common of these are epoxy novolacs, glycidyl ether of tetraphe-nolethane, bisphenol F-based resins, and aliphatic and cycloaliphatic resins. 

Glycidyl Ethers of Aliphatic Polyols. Glycidyl ether epoxy resins based on polyols provide greater flexibility and lower softening temperatures for the final cured epoxy system. The polyol is reacted with epichlorohydrin to produce these resins. These resins are generally not used alone because of water sensitivity and overall lack of toughness. However, they serve as modifiers for DGEBA-based epoxy resins. An idealized structure for a flexible resin based on this chemistry is shown in Fig. 2.9. 

Other products that may be epoxidized in this way include dihydric and trihydric phenols, aliphatic polyols such as glycerol, and simple alcohols such as butanol or alyl alcohol. These products, especially the monofunctional glycidyl ethers, are used at relatively low percentages to reduce the viscosity of formulations containing DGEBA resins. In this way, they act as reactive diluents. 

Glycidyl ethers of aliphatic polyols based on polyglycol, glycerin, and other polyols are flexible epoxy resins. They are used as reactive diluents and flexibihzers for solvent-free epoxy resin formulations. Epoxy-polyglycol resins that are produced from the reaction of epichlorohydrin and polyester polyols based on ethylene or propylene oxide are the most common of these types of flexible epoxy resins. Examples of typical commercial aliphatic epoxy resins are shown in App. C. 

In adhesive formulations, aliphatic amines are most commonly used to cure the DGEBA type of epoxy resin. Aliphatic amines are not widely used with the non-glycidyl ether resins, since the amine-epoxy reaction is slow at low temperatures. The reaction usually requires heat and accelerators for an acceptable rate of cure. Aliphatic amines are primarily used with lower-viscosity DGEBA resins because of the difficulty in mixing such low-viscosity curing agents with the more viscous epoxy resins. 

Various aliphatic and aromatic mono-glycidyl ethers are available that can be used as reactive diluents of many formulated epoxy structural adhesives. They are... 

Aliphatic and other specialty aromatic poly-funtional glycidyl ethers are also widely used either for viscosity reduction or improving one or more particular properties. Table 14.4 lists examples of some of these. 

Manufacture. Propylene oxide is copolymerized with allyl glycidyl ether in an aliphatic, aromatic, or chlorinated hydrocarbon solution using Vandenberg-type catalysts. A complete conversion and a uniform copolymer is obtained containing about 6% of AGE. 

Shechter and Wynstra ( ) proposed two possible types of reactions between phenol and a glycidyl ether. One involves direct reaction of the phenol with the epoxide the other involves direct reaction of the aliphatic hydroxyl, generated from the epoxide-phenol reaction, with another epoxide as shown in Reactions 22 and 23 ... 

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