Nadic acid

HO-Ar-OH = bisphenol-A HOOC-R-COOH = isophthalic, terephthalic, adipic, azelaic or nadic acid... 

The introduction of functional groups is suitable to control the chemical and physical properties of the polymer. However, the introduction of functional groups may cause a reaction of the unshared electron pairs of the functional groups with the active catalytic sites. Thus, the active sites of the catalyst are destroyed. In order to overcome this problem, a procedure has been developed, where the functionalized monomers, such as maleic acid, nadic acid or their anhydrides are grafted after the polymerization reaction (4,37). Grafting takes place as a radical reaction, using e.g., dicumyl peroxide. Other attempts use excessive amounts of catalysts. 

These drawbacks explain the development of a new concept introduced by a NASA team. According to this concept polymerization of monomeric reactants (PMR), a bisortho ester acid replaces the dianhydride and the monomethyl ester of the nadic acid is used instead of the nadic anhydride as shown in Fig. 5. These esters and the diamine are dissolved in methanol (or in a metha-nol/isopropanol mixture) in a molar ratio calculated to get the desired theoretical molecular weight [14]. These mixtures of reactants are currently used for the preparation of composites and adhesives [15a,b]. 

The cyclopentane-type dianhydride CpDA was synthesized by thermal dehydration of c/s,c/s,cw,ds-l,2,3,4-cyclopentanetetracarboxylic acid at 170-190 °C. The norbomane-type dianhydride BHDA was prepared from endo-nadic acid via three steps.[5] The H-NMR spectrum revealed that BHDA consisted of the two isomers, bicyclo[2.2.1]heptane-2-emfo,3-era/o,5-exo,6-ejco-tetracarboxylic dianhydride and the all-exo derivative. The ratio was estimated to be 1 1 from the spectrum. The structures and abbreviations of alicyclic monomers are illustrated in Figure 1. 

A 1 g (6.92 mmol) of nadic acid was added into 10 ml of dimethyl formamide. A 0.85g (4.46 moml) of N-(3-dimethylaminopropyl)-N -ethylcarbodiimide hydrochloride (EDC) and 1-hydroxybenzotriazole... 

FIGURE 7 FT-IR spectra of (a) nadic acid (b) BOC-NADIC (c) nadic hydrazine. 

A number of special purpose resins are available which employ somewhat unusual acids and diluents. A resin of improved heat resistance is obtained by using Nadic anhydride, the Diels-Alder reaction product of cyclopentadiene and maleic anhydride Figure 25.5). 

The methylated maleic acid adduct of phthalic anhydride, known as methyl nadic anhydride VI, is somewhat more useful. Heat distortion temperatures as high as 202°C have been quoted whilst cured systems, with bis-phenol epoxides, have very good heat stability as measured by weight loss over a period of time at elevated temperatures. The other advantage of this hardener is that it is a liquid easily incorporated into the resin. About 80 phr are used but curing cycles are rather long. A typical schedule is 16 hours at 120°C and 1 hour at 180°C. 

Nadic anhydride was also used to terminate an amic acid oligomer prepared from the reaction of 3,3 , 4,4 -benzophenonetetra-carboxylic dianhydride and 3,3 -methylenedianiline where the... 

Crosslinking of epoxy plastics through the hydroxyl groups of the repeat unit is used for prepolymers with low epoxide group contents. The most common curing agent is phthalic anhydride although other acid anhydrides such as tetrahydrophthalic, nadic methyl, and chloroendic anhydrides are used in specialty applications ... 

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)... 

The first nadimide end-capped oligomers were prepared using the unbalanced classical reaction of a dianhydride (BTDA) with an excess of diamine (MDA) and a quantity of nadic anhydride (NA) corresponding to the diamine excess (Fig. 4). The reaction was performed in NMP with a molecular ratio calculated in order to get a Mn of 1300 g mol-1 [12]. However the amic acid intermediate is not stable enough to allow a long term storage of the NMP solution... 

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. 

Fig. 10.23 The chemistry of PMR-15. The first stage is imidisation of the reactants, nadic anhydride monomethyl ester (NE), methylene dianiline (MDA) and 3,3 ,4,4 -benzophenonetetracarboxylic acid dimethyl ester (BTDE). The second stage is cross-linking of the norbomene end-caps.

NA=nadic anhydride BAPS=bisaminophenoxy phenylsulphone BDTE=benzene tetradicarboxylic diester TPA=terephthalic acid IPA=isophthalic acid BAPP=bisaminophenoxy phenyl 2-2 propane a An LC phase... 

Dimethylamino)benzoic acid 3- 246-644-8 Methyl nadic anhydride 2489... 

Later, McPherson (39) demonstrated that the Inclusion of a CTBN/liquid epoxy adduct enhanced both the flexibility and adhesion of a dimer acid flexibllized epoxy/brominated epoxy mixture when cured with a combination of chlorendic and nadic-methyl anhydrides. With an epoxy-glass laminate as substrate, such mixtures were coated at 0.5-2.0 mils thickness, cured, sensitized and copper plated (1.5 mils) by an electroless process. 90 peel testing (2 inches/mln. rate, 25 C) gave 14.0 pli peel force where 5.0 pli is considered normal. 

A 4 methyl yclohexene-l,2-dicarboxylic acid anhydride B methyl endomethylene-tetrahydrophthahc anhydride (Methyl Nadic Anhydride)... 

The saturated dicarboxylic acids act as modifiers. While aliphatic dicarboxylic acids can be used, the most common one is orthophthalic acid (added to the reaction mixture as an anhydride). The acid improves compatibility with styrene that is polymerized in the presence of the polyester to form hard, rigid, crosslinked materials. Other modifiers are used to obtain special properties. When a flexible product is needed, adipic or sebacic acids may be used instead. For better heat resistance endomethylene tetrahydrophthalic anhydride (nadic anhydride) may be utilized. Hame retardancy is achieved by using chlorinated dicarboxylic acids, like tetrachlorophthalic. 

The synthetic route for preparing the addition polyimide adhesive LARC-13 is displayed in Fig. 1. Appropriate quantities of 3,3 -methylenedianiline (m,m -MDA)f nadic anhydride (NA), and 3,3, 4,4 -benzophenone-tetracarboxylic acid dianhydr ide (BTDA) are combined in an amide solvent at a concentration of 50% solids by weight to form a 1300 molecular weight amic acid. This amic acid prepolymer is used as the adhesive resin and is later cured to the cross-linked polyimide by the removal of solvent,... 

PMR-I (PMR 15, PMR30, PMR 50) Monomethyl ester of 5-norbornene-2,3 dicarboxylic acid (Nadic ester), dimethyl ester of 3,3, 4,4 -benzophenone tetracarbo xylic acid dianhydride (BTDA) and 4,4 -methylene dianiline Mole ratio 2 2.087 3.087 Nadic 340(395)1316 [144-146]... 

Acid anhydride curing agents, especially the liquid anhydrides, are particularly important for epoxy resins. They cure at elevated temperatures but offer long pot life, good electrical properties, and heat resistance. Typical of these agents are phthalic anhydride and nadic methyl anhydride. The high-temperature properties of resin systans cured with these materials are better than those of resin systems cured with... 

Acid The development of liquid acid anhydrides Nadic methyl... 

The studies of the crosslinking reaction of a nadic end-capped imide, N, N -(ox-ydi-3,4 -phenylene)bis(5-norbornene-2,3-dicarboximide) in thermal and micro-wave processes were performed by Scola at al. (Fig. 14) [80]. The investigated starting resin (RP-46) consisted of polyimide precursors, 3,3, 4,4 -benzophenonetet-racarboxylic acid methyl ester (BTDE), 3,4 -oxydianiline (3,4 -ODA), and end capping reagent, 5-norbornene-2,3-dicarboxylic acid monomethyl ester (NE). The cure process proceeds in two steps imidization (1) and a thermally induced (retro-diene Diels-Alder) decomposition-recombination crosslinking step (2) (Fig. 14). 

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