Epoxy Anhydride-Cured

Epoxy (Anhydride-Cured) Epoxy resins may be crosslinked with various anhydrides by using a tertiary amine accelerator and heat. These cured polymers generally have good chemical resistance especially to acids. 

A simplified mechanistic model for the epoxy-anhydride cure of Reaction scheme 3 is given in Reaction scheme 5. 

The amount of vitrified material is raised from 10% to 50% over less than 2°C in the case of the epoxy-amine cured at 0.2°C min a more than 4°C temperature rise is necessary for the epoxy-anhydride cured at... 

In order to further understand die relationship between the activation energy of the cure reaction and the stability of the ligand bond of the metal chelates, Cobalt (II) chelate with a different ligand was used as the catalyst for the epoxy/ anhydride cure reaction. Figure 3 shows the chemical structure of Co(II) AcAc andCo(II)HFAcAc. 

A Kinetic Study of an Anhydride-Cured Epoxy Polymerization... 

The resin system selected to initiate these studies is a step-growth anhydride cured epoxy. The approach to the kinetic analysis is that which is prevalent in the chemical engineering literature on reactor design and analysis. Numerical simulations of oligomeric population density distributions approximate experimental data during the early stages of the cure. Future research will... 

Tanaka and Kakiuchi (6) proposed catalyst activation via a hydrogen donor such as an alcohol as a refinement to the mechanism discussed by Fischer (7) for anhydride cured epoxies in the presence of a tertiary amine. The basic catalyst eliminates esterification reactions (8). Shechter and Wynstra ( ) further observed that at reaction conditions BDMA does not produce a homopolymerization of oxiranes. 

Polystyrene insulation on magnet wire 0.49 Encapsulated with phthalic anhydride cured bisphenol A-epichlorohydrin epoxide (epoxy hot melt cast). Impregnated. 

R Musto, M. Abbate, G. Ragosta and G. Scarinzi, A smdy by Raman, near-infrared and dynamic-mechanical spectroscopies on the curing behaviour, molecular structure and viscoelastic properties of epoxy/anhydride networks, Polymer, 48, 3703-3716 (2007). 

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. 

This paper rerports an investigation of the yield behavior of several amine and anhydride cured DGEBA resin systems. The Argon theory is used to assess the controlling molecular parameters from the experimental results. Such parameters are then compared with the known chemical structures of the resins. The mechanisms of plastic flow in thermoset polymers such as epoxies is demonstrated. 

The plastic deformation in several amine and anhydride cured epoxy resins has been studied. The experimental results have been reasonably interpreted by the Argon theory. The molecular parameters determined from the data based on the theory reflect the different molecular structures of the resins studied. However, these parameters are in similar enough range to also show the structural similarity in these DGEBA based systems. In general, the mechanisms of plastic deformation in epoxy resins below T are essentially identical to those in amorphouE thermoplastics. The yield stress level being related to the modulus that controls the intermolecular energy due to molecular deformation will, however, be affected by the crosslinks in the thermosets. 

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

The anhydride cured epoxies displayed a prominent carbonyl group of HHPA. The peak at 70 ppm was assigned to the products of the reacted epoxide groups. This peak was predominant in all four groups, piperidine-CTBN, MPDA, HHPA and NMA-DMBA. 

Tertiary amines are used to accelerate both amine and anhydride cures of epoxy resins (B-67MI11501). Certain heterocyclic amines have been used for this purpose, including pyridine and piperidine. In the case of anhydride cures, the use of an amine catalyst not only accelerates the cure, but also improves the thermal stability of the cured resin. 

The catalytic effect has been explained in terms of the activation of the anhydride by interaction with the amine to give a zwitterionic intermediate (47 Scheme 10) (B-68MI11501). Imidazoles have also been suggested as accelerators for anhydride cures (68USP3394105). A review of the patent literature (B-77MI11502) shows that several heterocyclic compounds are of interest as curatives for epoxy resins. 

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