Bisphenol A-type epoxy

The DIBF OPPI combination has been shown to efficiently cure a wide variety of epoxies including cycloaliphatics. With this photoinitiator it is possible to cure bisphenol A epoxies such as Epon 828 quickly without the need for acrylation of the epoxy. Cycloaliphatic epoxies were of special interest because they were expected to react much faster than bisphenol A type epoxies. Those tested include 3,4-epoxycyclohexylmethyl-3 ,4 -epoxycyclohexyl-carboxylate (UVR 6110), bis(3,4 epoxy-cyclohexylmethyl) adipate (UVR 6128), and 1,2-epoxy-4-vinylcyclohexane (vinyl cyclohexene oxide). It was found that the vinyl cyclohexene oxide reacted rapidly, but work with it was discontinued because it has a fairly high vapor pressure (2 torr at 20 °C), an intense odor, and the photoinitiator does not dissolve in this resin. 

Bisphenol A type epoxies such as Epon 828, were also cured with the DIBF OPPI combination. When a modifier, Heloxy 505 (a low viscosity polyepoxide modifier) was added, viscosity was reduced and adhesion to the metal surface and impact resistance were improved as compared with the bisphenol A only. Surprisingly cure was faster than with the Union Carbide cycloaliphatic resins, but charring of the resin during cure was a problem. 

Evans et al. [43] carried out 4 MeV electron irradiations of 14 different epoxy resins at 77 K which were selected from a large number of resin systems after screening tests on thermal shock at cryogenic temperatures [44]. The results of flexural tests show that most of these irradiated resins possess only moderate resistance to radiation. Takamura and Kato [45] tried to irradiate the bisphenol-A type epoxy resins with various hardeners at 5 K in a fission reactor and reported that the compressive strength of these epoxy resins decreased sharply after a combined neutron and y-ray irradiation equivalent to a dose of about 107 Gy. 

If a rubber-like polymer is used as the vinyl polymer, this IPN will show good damping properties at elevated temperatures. So, butyl acrylate, ethylene glycol dimethacrylate, phenolic novolac, and bisphenol A type epoxies were used as IPN components. The dynamic mechanical properties of these IPNs were examined first, because the loss tangent is very important to damping properties. Then the damping properties of IPN and commercial chloroprene rubber were measured at various temperatures. 

We have investigated the recovered glassfiber-resin powder for its properties as a filler for epoxy resin compounds which are used as paints or adhesives, and compared it to conventional fillers, such as talc and calcium carbonate. The epoxy resin compound, composed of bisphenol A type epoxy resin (50.0wt%), aliphatic polyamine type hardener (18.0wt%) and filler (32.0%), was prepared. Strength and thermal expansion properties were measured for the molded epoxy resin compound cured 23°C for 7 days. Viscosity was measured for the epoxy resin compound before adding the hardener. Adhesive strength was measured by tearing two ferric boards bonded with the epoxy resin compound which was composed of bisphenol A type epoxy resin (49.2wt%), polyaminoamide type hardener (18.0wt %), and filler (32.8wt%), and was cured at 23°C for 7 days. 

We investigated the use of the molding resin powder (<150 m) as a filler for construction materials composed of bisphenol A type epoxy resin and amine type hardener, and compared the material properties with those produced with a silica powder filler (<150 fi m). Furthermore, the effect of surface treatment of the molding resin powder on these properties was examined by using epoxy or amino silane coupling agents, which were added at lwt% to the molding resin powder and heated at 100°C for 1 hr. 

An aqueous Friedel-Crafts reaction has also been used in polymer synthesis. The acid-catalyzed polymerization of benzylic alcohol and fluoride functionality in monomeric and polymeric fluorenes was investigated in both organic and aqueous reaction media. Polymeric products are consistent with the generation of benzylic cations that participate in electrophilic aromatic substitution reactions. Similar reactions occurred in a water-insoluble Kraft pine lignin by treatment with aqueous acid. A Bisphenol A-type epoxy resin is readily emulsified in aqueous medium with an ethylene oxide adduct to a Friedel-Crafts reaction product of styrene and 4-(4-cumyl)phenol as emulsifier.Electrophilic substitution reaction of indoles with various aldehydes and ketones proceeded smoothly in water using the hexamethylenetetramine-bromine complex to afford the corresponding Z A(indolyl)methanes in excellent yields.InFs-catalyzed electrophilic substitution reactions of indoles with aldehydes and ketones are carried out in water.Enzymatic Friedel-Crafts-type electrophilic substitution reactions have been reported. ... 

Bisphenol A type epoxy resin (Epikote 828 Shell) cured with modified amine (Epomate B002 Shell) was used as the matrix of the dismantlable adhesive (re-sin/matrix=2 1 w/w). Fig. 34.3 shows their chemical structures. The bulk adhesive was cured at room temperature for 24 h before the experiments. Cured bulk resin mixed with the microcapsules was used for the specimens to measure the volume change. 

A standard bisphenol A type epoxy resin, Epon 828 from Shell Chemical Co. U.S.A., and an amine type curing agent, Versamld 140 from General Mills Chemical, U.S.A., were used as received. The dleplsulflde resin was synthesized from Epon 828. 

Ara Araki, W., Adachi, T., Yamaji, A., Gamou, M. Fracture toughness of bisphenol A-type epoxy resin. J. Appl. Polym. Sci. 86 (2002) 2266-2271. 

Bisphenol-A type epoxy resin E-51 was produced by Wuxi Resin Factory. The epoxy value was 5.1 meq/g. 2-Ethyl-4-methyl-imidazole from Tienjin Second Chemicals Factory was a special reagent and used as received. 

The compound has functional groups that support dimerization type crosslinking and cationic polymerization upon UV exposure (A, = 300—360 nm).. Photodimerization of the chalcone-epoxy compound was confirmed by UV-visible and IR absorbance changes of the C=C double bond of the chalcone unit. Additions of small amounts of onium salts will also photoinitiate cationic polymerization of the epoxy groups present in the above chalcone-epoxy compound by exposine to UV. This ultra-violet light cured chalcone-epoxy compound was reported to possess excellent thermal stability and compares well with conventional UV-cured Bisphenol A type epoxy resins. (see Chapter 3)... 

Three types of vinyl ester resins are commercially available (1) conventional or resilient grades based on bisphenol A-type epoxies (2) fire-retardant grades based on tetrabromobisphenol-A epoxies and (3) high-heat grades based on novolac epoxies. 

Two types of epoxy resins were used in this study. They were bisphenol A type epoxy resins (EPON 828 fiom Shell Chemicals), and cycloaliphatic qwxy resins (ERL 4221 from Union Carbide). The epoxy equivalent weight (EEl of ERL 4221 was 134 g/mol, and the EEW of EPON 828 was 188 g/mol. The curing agent used in this study was hexahydro-4-meth)dphthalic anhydride (HMPA), purchased from Lindau Chonicals. The molecular weight of HMPA was 168.2 g/mol. The chemical structures of the epoxy resins and HMPA are shown in Figure 1. 

In this work, the tonghness effect of carbon black (Ketjenblack EC-300j, Ketjem Black International Co., Japan) and nanoclay (Cloisite 93A, Southern Clay Products, United States) on the modified bisphenol A-type epoxy resin (YD-114F, Kukdo Chanical, Korea) was investigated at room (25 C) and cryogenic (-150°C) temperatures. 

Epoxy (EP) resin contains epoxy groups in its molecular structure. There are many types of EP resin, but more than 90% of EP is bisphenol A-type epoxy resin, which is formed via the polymerization of bisphenol A and epichlorohydrin. The molecular structure is... 

The values are in the same range as those reported for bisphenol-A-type epoxies, ca. 85 kcal/mole (23), and equal to the value reported for creep in PS at its Tg (23b). However, Ferry (23b) points out that this activation energy is actually that for an elementary flow process. The values listed are for the onset of segmental motion, at Tg. 

Pressure Sensitive. Mixtures of nitrile rubber and epoxy resin have been described to be useful as pressure sensitive adhesives. One such system combines nitrile rubber, a bisphenol A type epoxy resin methacrylate ester, a product... 

Zhu et al. and Huang et al. employed a block copolymer/homopolymer system (poly(ethylene oxide)-h-polystyrene/polystyrene) in order to study the crystallization of PEO under hard and soft confinement [180, 244]. In a related work, Xu et al. prepared blends of poly(oxyethylene)-h-poly(oxybutylene) and polystyrene/poly(oxybutylene) and compared confined versus breakout crystallization [249, 308]. Guo et al. studied a block copolymer/thermoset blend constituted by poly(ethylene)-h-poly(ethylene oxide)/bisphenol A type epoxy resin. The authors reported the nanoconfinement effect on the crystallization kinetics of the PE block [309]. 

Commercial cement modifiers used were based on a bisphenol A-type epoxy resin, diglycidyl ether of bisphenol A (DGEBA), which was mixed with three types of hardeners, modified polyamide-amine (MPAA),modified aliphatic polyamine (MAPA).and modified amine (MA) at the hardener contents recommended by the respective manufacturers. The hardener content was expressed as follows ... 

Epoxy-modified mortars which are prepared by mixing most popular bisphenol A-type epoxy resin with commercial modified polyamide-amine hardener, polyalkyl aryl sulfonate-type water-reducing agent, polyoxyethylene nonylphenol ether-type nonionic surfactant and silicone emulsion-type antifoamer into cement mortar have excellent properties comparable to ordinary polymer-modified mortars using latex-type cement modifiers[5]. The optimum mix proportions of the epoxy-modified mortars are shown in Table 2. Their disadvantage is a need of much higher polymer-cement ratio than the ordinary polymer-modified mortars. Therefore, the development of low-cost, effective dispersants is expected in the near future. 

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