Epoxy resins cured with anhydrides

Resins used were two types of epoxy resins cured with anhydride and amine and iso-phthalic type polyester resin. 

Different behaviors and mechanisms were clearly recognized between these resins. Epoxy resin cured with amine showed no degradation during immersion because of its stable crosslinks. Epoxy resin cured with anhydride showed the uniform corrosion with the softening and dissolution of the surface and also behaved similar to the oxidation corrosion of the metal at high temperature obeying linear law. 

Ward MJ, Davies D Asthma due to grinding epoxy resin cured with phthalic anhydride. Clin Allerg 12 165-168, 1982... 

Fig. 6. DSC results for epoxy resin cure with a carboxylic acid anhydride a) Set of displaced thermo-grams b) Curve deduced from a) and used to obtain isothermal cure data at temperature T. (From Ref.65), Fig. 3)...

Dynamic Mechanical Properties of Epoxy Resins Cured with Carboxylic Anhydride... 

Table 6. Dynamic mechanical properties for epoxy resin cured with acid anhydrides...

The middle infrared region of the cured crosslinked polymers shows bands in the 3480 cm"i, the 1200-1300 cm" and the 1000-1100 cm l region, the latter two increase with phthalic anhydride concentration. A band at 1420 cm"l along with the 3480 cm i 0-H stretch band appears in the spectra of the epoxy resin cured with curezol only. This band is a weak band in the uncured epoxy resin and is interpreted to be associated with a secondary hydroxyl group arising from epoxy ring opening (1 ). Bands at 1080 cm"i and 1290 cm"i also are present and are probably the C-0 stretch... 

Casting. Castings of liquid epoxy resins cured with hexahydrophthalic anhydride (HHPA) were prepared by heating the liquid resin in a stirred 3-necked flask to which the calculated amount of premelted HHPA was added. A vacuum was drawn to partially degas the mixture then 2 phr benzyldimethylamine (BDMA) was added as accelerator. After further degassing, the mixture was poured into casting molds prepared as described above. The filled molds were put into an oven at the desired gelling temperature subsequently, either the oven was reset to the final cure temperature or the molds were transferred to a second oven, as convenient. 

Figure 3.6. Non-reversing heat flow and change in heat capacity (C ) during cure of an epoxy resin cured with an anhydride at 80 °C. The cure time needed to reach a halving of Cp is marked as t. Adapted from Van Assche et al. (1997).

Uses Antioxidant stabilizer catalyst intermediate R.T. epoxy curing agent activator for epoxy resins cured with wide variety of hardener types incl. polyamide, amidoamines, polymercaptans, and anhydrides for coatings, adhesives, castings, potting, encapsulation Manuf./Distrib. ChemService http //www.chemservice.com, Sigma Trade Name Synonyms Ancamine 1110 [Air Prods./Perf. Chems. http //WWW. airproducts. com]... 

It is well known that the epoxy-amine polymers have decreased thermal stability in comparison with the epoxy-anhydride polymers [3-5]. The investigation of the effects of the salts of manganese, nickel, chromium, and cerium on the thermal (in nitrogen) and thermo-oxidative (in air) degradation of the bisphenol A-based epoxy resins cured with triethylene tetramine indicated that the compounds of manganese, chromium, and cerium do not affect the thermal degradation of the polymers, but diminish their thermo-oxidative stability and lessen the breakdown temperature by 80-100 C. The nickel salts affect neither the thermal nor thermo-oxidative degradation of these epoxy polymers [252]. 

Brominated epoxy resins cured with halogenated anhydrides to give flame-retardant polymers [147]. 

The bisphenol A-derived epoxy resins are most frequendy cured with anhydrides, aUphatic amines, or polyamides, depending on desired end properties. Some of the outstanding properties are superior electrical properties, chemical resistance, heat resistance, and adhesion. Conventional epoxy resins range from low viscosity Hquids to soHd resins. 

In order to obtain cured products with higher heat distortion temperatures from bis-phenol epoxy resins, hardeners with higher functionality have been used, thus giving a higher degree of cross-linking. These include pyromellitic dianhydride IV, and trimellitic anhydride V. 

Heat distortion temperatures of resins cured with pyromellitic dianhydride are often quoted at above 200°C. The high heat distortion is no doubt also associated with the rigid linkages formed between epoxy molecules because of the nature of the anhydride. The use of these two anhydrides has, however, been restricted because of difficulties in incorporating them into the resin. 

Resins used were two types of epoxy resins (EP) and an unsaturated polyester resin (UP) as shown in Figure 1. EP is the bis-phenol-A type resin cured with methyl-tetrahydrophthalic anhydride (MTHPA) or 1,8-p-menthandiamine (MDA). UP is the iso-phthalic type resin which has ester bonds in the main chain and is crosslinked by styrene (10). 

It is evident that relaxation studies in the solid state can look at the motions which are responsible for the mechanical properties of the cured epoxy systems 43). Therefore, Garroway, Moniz and Resing continued to do relaxation studies 61). Garroway, et al. looked at four epoxy polymers based on the DGEBA resin. Two of the epoxy resins were cured with amines and the other two were cured with anhydrides. Proton enhanced spectra of the epoxy systems were generated. The solid state spectra were compared to the solution spectra of the unreacted epoxy. The< epoxy resin of interest was again DGEBA which was reacted with ... 

In Chapter 2 the DSC technique is discussed in terms of instruments, experimental methods, and ways of analysing the kinetic data. Chapter 3 provides a brief summary of epoxy resin curing reactions. Results of studies on the application of DSC to the cure of epoxy resins are reviewed and discussed in Chapter 4. These results are concerned with the use of carboxylic acid anhydrides, primary and secondary amines, dicyanodiamide, and imidazoles as curing agents. 

The hisphenol A-derived epoxy resins are most frequently cured with anhydrides-, aliphatic amines, or polyamides. 

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