Diaminodiphenylmethane curing

By contrast with tertiary amines used in catalytic quantities, primary and secondary amines or acid anhydrides may be used to bring about the cure of epoxy resins by reaction in stoichiometric proportions. A typical amine curing agent used at this level is diaminodiphenylmethane (DDM), which reacts with an individual epoxy-group in the way shown in Reaction 4.17. 

Diaminodiphenyl sulfone (DDS) cured tetraglycidyl-4,4 -diaminodiphenylmethane (TGDDM) epoxies are the mpst common composite matrices utilized in high performance fibrous composites prepared from prepregs. The structures of the unreacted TGDDM epoxide and DDS monomers are illustrated in Fig. 3. The TGDDM epoxide monomer is a liquid at 23 °C, whereas the DDS monomer is a crystalline... 

The cure of tetra-N-glycidyl-4,4 -diaminodiphenylmethane (TGDDM), as a commercial grade, with 4,4 -diaminodiphenylsulphone (DDS) has been studied by Barton 89), in the temperature range 170-220 °C. The data were fitted to Eq. (4-11) with m = 1 and n = 1 or 2. 

Some aromatic diamines used as curing agents, such as 4,4 diaminodi-phenyl derivatives or 3,3 Dichloro 4,4 diaminodiphenylmethane (MOCA), have been investigated and have been declared to have suspect carcinogenic properties. All local rules and regulations must be adhered to if these materials are used. 

Murayama8> studied a series of resins from diglycidyl ether of Bisphenol A (DGEBA) cured with varying quantities of diaminodiphenylmethane (DDM). These cured resins had the same main chain structure, but differed in the degree of crosslinking. Izumo 25) performed similar studies by using diethylenetriamine (DETA) as a... 

Figure 1. Curing of tetraglycidyl diaminodiphenylmethane with thermally latent catalysts and 4,4 -diaminodiphenyl sulfone.

Most of the commerically available high-performance moulding materials use epoxidized cresol-novolak/novolak (especially phenolic novolak) as a base. Systems with amine curing agents, for instance 4,4 -diaminodiphenyl-sulfone (2) or 4,4 -diaminodiphenylmethane, do provide high-quality moulding substances with a thermo-mechanical performance comparable to our system. They are, however even less stable under storage. 

Kinetics of curing of a haloid containing diepoxide based on hexachlorobenzene has been studied. This oligomer (EPS-1) was cured by 4,4 -diaminodiphenylmethane (DDM) in the stochiometric ratio DDM EPS-1. Haloid containing epoxy polymer with conditional designation EPS-l/DDM has the chemical structure shown in Figure 10.1. 

Curing with 4,4 -diaminodiphenylmethane // with 3,3 -dichloro-4,4 -diaminodiphenylmethane... 

Figure 12.5 shows an example of the cured structure of a thermoset resin using two different epoxide monomers with two different amine hardeners. The epoxies are triglycidyl p-aminophenol (TGAP) and tetraglycidyl 4,4-diaminodiphenylmethane (TGDDM), which are tri- and tetra-fiinctional, respectively (n = 3 and n = 4, respectively) and the two hardeners are 4,4-diamino-diphenylsulphone (DDS) and dicyandiamide (DICY). 

A BMI formulahon, a mixture of 4,4 -diaminodiphenylmethane-based BMI ( 50%), styrene, 2-hydroxyethylmethaciyIate and a curing agent (trigonox HM)... 

How long will be required for phase separation to oeeur for an epoxy eontaining CTBN and cured with diaminodiphenylmethane if the volume fraction of CTBN is 5.2% and the value of the constants k and n are respectively 426 sec and 0.674. How long will be required for gelation if the constants for the process are 1396 sec and 0.431 If the volume fraction of CTBN is increased to 10.6%, will the times to phase separation and gelation be increased or decreased ... 

A large group of curing agents comprises derivatives of ethylenediamine. Generally, aromatic amines such as 4,4 -diaminodiphenylmethane require higher curing temperatures than aliphatic amines such as the ethylenediamine derivatives, which cure the epoxy resin at room... 

A widely studied nanohybrid system is based on epoxy-siUca [148,149], which is generally prepared upon blending the epoxy monomer and siUca nanoparticles, followed by the addition of a hardener to perform the curing reaction (e.g., diaminodiphenylmethane [150], diaminodiphenylsulfone [151], diethylphosphite [150], PA-amine [152, 153], or hexahydro-4-methylphthalic anhydride [154]). The compatibility between the epoxide compounds and the colloidal silica was optimized upon mixing the diglycidylether of bisphenol-A together with colloidal suspensions of silica nanoparticles dispersed in methylisobutylketraie [150]. 

Besides the potential irritants, such as cleansing agents and inks, the classic allergens, such as rubber chemicals, paraphenylenediamine and its derivatives, and preservatives (Adams 1983), new allergens have added to the spectrum of allergens in silk-screen printers. They are the acrylate components of the UV-curing compounds, epoxy resin, diaminodiphenylmethane, and triglycidyl isocyanurate. 

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