Methyl anhydride

The resin is more than 90% DGEBA with the remaining material predominately at n=1. The curing agent, nadic methyl anhydride (NMA), is manufactured by Allied Chemical. The catalyst was benzyl dimethylamine (BDMA). All materials were stored in a desiccator to minimize moisture pickup. 

Step-growth polymerization. Epoxy resins were prepared from nadlc methyl anhydride and Epon 828. This blfunctlonal oxirane also supplies reactive hydrogen sites. The major component is at 1=0, minor components include oligomers with 1=1,2,3. Their concentrations rapidly diminish as degree of polymerization Increases. 

Figure 2. Solid-state spectra of four different epoxies (hosed on the resin diglycidyl ether of bisphenol-A) are compared with the liquid-state spectra of their respective unreacted components, The chemical compositions are in Table I. Here the epoxies are identified by their main curing agent (a) PIP—piperidine (b) MPDA—metaphenylene diamine (c) HHPA—hexahydro-phthalic anhydride (d) NMA—nadic methyl anhydride.

Table lb. Infrared and Raman Band Assignments for Nadic Methyl Anhydride... 

Table lc. Infrared Special Changes During the Crosslinking of a Stoichiometric Nadic Methyl Anhydride/EPON 828 Mixture Catalyzed by 2.0% Weight Benzyldimethylamine... 

Resing and Moniz 60) cured DGEBA with three different curing agents, piperidine, hexahydrophthalic anhydride (HHPA) and nadic methyl anhydride (NMA). Spectra were collected with C-13 NMR using cross polarization and high power decoupling. 

Garroway, Ritchie, and Moniz 70 continued the characterization of epoxy polymers with respect to molecular motion using variable temperature, solid state C-13 NMR. DGEBA was the epoxy of interest. The DGEBA was cured with piperidine, m-phenylene diamine, hexahydrophthalic anhydride and nadic methyl anhydride. The piperidine cured DGEBA had the best resolved polymer spectra. This system... 

BA BuE-PA BE-HET BE-HHPA BE-MA BE-PA BE-SA CA CHX DMA DMBA DY 062 GA HEB HHPA HMTA MA MTHPA NMA benzoic acid monobutylester of phthalic acid monobenzylester of hexachloroendomethylenetetrahydrophthalic acid monobenzylester of hexahydrophthalic acid monobenzylester of maleic acid monobenzylester of phthalic acid monobenzylester of succinic acid citraconic anhydride cyclohexanol N,N-dimethylaniline dimethylbenzylamine high boiling tertiary amine (Ciba Geigy AG) gjptaric anhydride 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone hexahydrophthalic anhydride hexamethylenetetramine maleic anhydride methyltetrahydrophthalic anhydride nadic methyl anhydride (methylbicyclo[2.2.1]heptene-2,3-dicarboxylic anhydride isomers)... 

Feltzin et al.73) have reported the first-order kinetics and express the rate constant by the Arrhenius equation. Thus, for the curing of diglycidyl ether of Bisphenol A with nadic methyl anhydride, initiated by benzyldimethylamine, we have3 ... 

Antoon and Koenig 67) found a first-order dependence with respect to the tertiary amine, but they were not able to distinguish between zero-, first-, and second-order kinetics with respect to monomers. Approximately the same fit was obtained for all mentioned orders below the gel point. Peyser and Bascom reported first-order kinetics for the curing of the diglycidyl ether of bisphenol A with hexahydrophthalic anhydride 94) and second-order kinetics with respect to the same epoxide cured with nadic methyl anhydride 93). They also pointed out the uncertainty in determining the reaction order. 

TABLE 4.3 Thermal Weight Loss, Weight Percent, of Nadic Methyl Anhydride Cured Epoxy Novolac Resin (Cured 2 h at 90°C, 4 h at 165°C, and 16 h at 200°C)4... 

After the primary amines, acid anhydrides are the next most important class of epoxy curing agents, although these are not used as often in adhesive systems as they are in casting compounds, encapsulants, molding compounds, etc. The most common types of anhydrides are hexahydrophthalic anhydride (HHPA), phthalic anhydride (PA), nadic methyl anhydride (NMA), and pyromellitic dianhydride (PMDA), although there are several others. Chemical structures of several anhydrides are illustrated in Fig. 5.6. 

Nadic methyl anhydride (NMA) is the most versatile of all the anhydrides. NMA is a liquid of viscosity about 200 cP at room temperature, and it is readily soluble in epoxy resins. The mix ratio is 60 to 90 pph when used with a liquid DGEBA epoxy resin. At 60 pph and with no catalyst, the working life is about 2 months and with the incorporation of 0.5 pph DMP-30 as an accelerator, the working life reduces to 4 to 5 days. 

It has also been shown in several studies that the combination of stress, temperature, and moisture can accelerate the hydrolytic instability of certain epoxy adhesives. In an FTIR study of the effect of moisture on DGEBA epoxy cured with nadic methyl anhydride, spectra changes were observed in stressed specimens aged for 155 days at 80°C and 100 percent RH.47 This was attributed to the slow, stress-induced hydrolysis of ester groups. In another study,... 

NMA Nadic methyl anhydride 60-90 Liquid anhydride having long pot life at room temperature ... 

Methyl- -anhydrid VIII, 478 (Anhydrid-Bild.) E5, 638 (Anhydrid-Bild.)... 

Phosphinsaure Ethyl-(methoxy-methyl)- -anhydrid E2, 176 (R2PO —Cl + Amin) Pyrophosphonsaure Ethan- -di-ethylester XII/1, 610 Pyrophosphorigsaure -tetra-ethylester XII/2, 123 (P-O-Kuppl.) XV/2, 235, 424 (Kond.). 

Epon 812 substitute and Epon A 62 mL Epon 812 substitute and 100 mL dodecenyl succinic anhydride (DDSA) Epon B 100 mL Epon 812 substitute and 89 mL nadic methyl anhydride (NMA) mix together 10 mL Epon A and 15 mL Epon B add 0.5 mL 2,4,6-tri (dimethylamino-methyl) phenol (DMP-30), and mix well (see Note 4). 

Beilstein Handbook Reference) 5-Norbornene-2,3-dicarboxylic anhydride, methyl- BRN 0162395 EINECS 246-644-8 Epicure NMA Hardener HY906 HSDB 6093 Kayahard MOO MEA 610 4,7-Methanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-methyl-, Methendic anhydride Methyl-5-norbornene-2,3-dicarboxylic anhydride Methyl nadic anhydride Methylbicyclo(2.2.1)heptene-2,3-dicarboxylic anhydride isomers Methylendic anhydride Methylnorbornene-2,3-dicarboxylic anhydride Nadic methyl anhydride NMA TK10 524 XMNA. 

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