Reaction with epoxy resin

Epoxy Resins. Polysulftdes may also be cured by reaction with epoxy resins (qv) according to the reaction in equation 2. Amines or other catalysts are used and often primary or secondary amine resins are cured together with the polysulfide. 

Lin, C. H., Synthesis of novel phosphorus-containing cyanate esters and their curing reaction with epoxy resin, Polymer, 2004, 45, 7911-7926. 

The mapping shown in Fig. 1 includes references to SBR and styrene block copolymers in the PB search. Removing these citations from the database reduced the number to 4297, which can be seen mapped in Fig. 3. the area of high activity is centered on hydroxy terminated PB (HTPB). Low-Mn HTPB can be prepared by a variety of polymerization processes such as radical, anionic, or even using acyclic diene metathesis (ADMET).f The HTPB has a variety of uses as a propellant. " Other uses include reaction with epoxy resins, nylon, urethane, or even in the formulation of adhesives.t" The use of HTPB as an oxygen scavenger in polyamide, polyvinyl alcohol, and multilayer... 

The liquid dimer polyamides were first described by Bradley (25). but their reactivity with epoxy resins was first recognized by Renfrew and Wittcoff (26). In reaction with epoxy resins the amine-containing dimer polyamides contribute to water resistance, increased flexibility and adhesion, and most importantly corrosion inhibition properties. 

HAZARD RISK Very dangerous fire and explosion hazard when exposed to heat or flame explosive reaction with epoxy resin, sodium hydroxide and oxygen decomposition emits acrid smoke and fiimes NFPA Code H 3 F 4 R 2. 

Anhydrides are also high temperature curing agents. The reaction with epoxy resins is slow in the absence of an accelerator, and requires quite large quantities. Typical substances used include methyl nadic anhydride and hexahydrophthalic anhydride. (Methyl nadic anhydride is a convenient liquid at room temperature, whereas nadic anhydride is a solid.)... 

Amines generally do not need a catalyst, as the reaction with epoxy resins occurs spontaneously at room temperature. Therefore, amine curing agents can be used... 

The most common way to convert LP polymers to solid elastomers is to couple the terminal -SH groups. This is done either by oxidation to disulfides using organic or inorganic oxidizing agents or by reaction with epoxy resins, aromatic amines, diisocyanates, aldehydes, etc [16,35] ... 

Other Coatings Resins. A wide variety of other resin types are used in coatings. PhenoHc resins, ie, resins based on reaction of phenols and formaldehyde, have been used in coatings for many years. Use has been declining but there are stUl significant appHcations, particularly with epoxy resins in interior can coatings. 

The addition—reaction product of bisphenol A [80-05-07] and glycidyl methacrylate [106-91-2] is a compromise between epoxy and methacrylate resins (245). This BSI—GMA resin polymerizes through a free-radical induced covalent bonding of methacrylate rather than the epoxide reaction of epoxy resins (246). Mineral fillers coated with a silane coupling agent, which bond the powdered inorganic fillers chemically to the resin matrix, are incorporated into BSI—GMA monomer diluted with other methacrylate monomers to make it less viscous (245). A second monomer commonly used to make composites is urethane dimethacrylate [69766-88-7]. 

The reactions of carboxyUc acids and anhydrides with epoxy resins have been extensively studied in a variety of investigations, particularly References 27—31. The general reaction of epoxide resins and anhydrides is... 

Polymer systems are now available which may be cured by reaction of epoxy resin compounds with the phenolic hydroxyl groups. Such reactions do not evolve volatile by-products. These materials are showing promise in the area of heat-resisting electrical insulation laminates. 

Unsaturated acrylic oligomers are made from unsaturated acrylic monomers. For example, an epoxy acrylate may be made by reaction of acrylic acid with epoxy resin. 

Curing reactions of epoxy resins with formaldehyde resins 0... 

This reaction is an example of a two-pack epoxy finish where the n value of the epoxy resin is 8 to 12. Although giving a high degree of chemical resistance the reaction is sluggish so the common two-pack finishes are usually based on polyamines with epoxy resins having n values of 0 to 2. 

An interesting approach to maleimide-terminated phenoxy resin has recently has described (42). para-Maleimidobenzoic acid was reacted with diglyci-dylbisphenol-A epoxy resin in the presence of catalyst to provide the bismale-imide of Fig. 13. Instead of diglycidyl bisphenol-A, linear epoxy resin pre-polymers can be used in this reaction to form a maleimide terminated phenoxy resin. Another suitable functionalized monomaleimide is m- or p- N-(hydroxyphenyl) maleimide which is synthesized from maleic anhydride and m-aminophenol in DMF as a solvent at 70 °C. The purified hydroxyphenyl maleimide was reacted with epoxy resin to form novel BMIs as outlined in Fig. 14. The new BMI and phenoxy oligomers polymerize at temperatures of 200-220 °C, but the cure temperatures can be significantly lowered when catalysts such as imidazoles or triphenylphosphine are added. The cured homopolymers show Tg of 140 and 230 °C for the n = 2 and the n = 1 polymer, respectively(43). 

Heat resistant resin compositions based on BMI/aminophenol-Epoxy blends are achieved by reacting a BMI/p-aminophenol 1 1 adduct with epoxy resin (62). Both the secondary amine and phenol functionality may react with the epoxy resin and subsequently cure through an imidazole catalyst. Imidazole catalysts promote both the epoxy/phenol reaction and the anionic maleimide crosslinking. The formation of a 1 2 BMI/aminophenol adduct, as in Fig. 20, is claimed in a patent (63). The hydroxy terminated BMI/aminophenol adduct is an advantageous curing agent for epoxy resins when high temperature performance is desired. 

This article summarizes and analyzes the results obtained for the anionic copolymerization of cyclic ethers with cyclic anhydrides. This reaction is of great practical importance, especially as curing reaction of epoxy resins and is also used for the preparation of linear polyesters with special functional pendant groups. 

For the copolymerization of epoxides with cyclic anhydrides and curing of epoxy resins, Lewis bases such as tertiary amines are most frequently used as initiators. In this case, terminal epoxides react with cyclic anhydrides at equimolar ratios. The time dependence of the consumption of epoxide and anhydride is almost the same for curing 35-36> and for model copolymerizations 39,40,45). The reaction is specific 39,40) to at least 99 %. In contrast, the copolymerization with non-terminal epoxides does not exhibit this high specificity, probably because of steric hindrances. The copolymerization of vinylcyclohexene oxide or cyclohexene oxide is specific only to 75-80 % and internal epoxides such as alkylepoxy stearates react with anhydrides only to 60-65 %. On the other hand, in the reaction of epoxy resins with maleic anhydride the consumption of anhydride is faster 65the products are discoloured and the gel is formed at a low anhydride conversion 39). Fischer 39) assumes that the other resonance form of maleic anhydride is involved in the reaction according to Eq. (33). 

Sensing mechanism of the modified sensor. The sensing mechanism in this modified sensor should be essentially the same as that of the unmodified one. It is noteworthy that a stationary short circuit current was obtained in spite of such sensor construction that the counter electrode was covered with Epoxy resin. Since the sensing electrode is placed in the same situation as the unmodified sensor, this fact indicates that the cathodic reaction is allowed to take place stationarily at the counter electrode. The proton conductor membrane is as thin as 0.2 mm, so that the reactant 02 and the produced H20 will permeate the membrane as shown in Figure 11. A part of H2 will naturally also permeate through the membrane, but the transfered H2 will be consumed by the reaction with 02 electro-chemically or catalytically at the counter electrode. 

Modeling with the Smoluchowski-like equation generalized to take into account FSSE is not limited to the simple RAf polymerization. A kinetics approach similar to that described in this section have been used to study crosslinking reactions of epoxy resins with components introduced into the system at different times [17]. Kinetic equations analogous to Eq. (101) have been derived [48] for an RA2 + R B2 system as well as for systems containing 3-functional monomers having functional groups of intrinsically different reactivities [49]. 

FIGURE 4.3 Reaction of epoxy resins with acrylic to produce epoxy acrylate resin.10... 

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