Primary aliphatic polyamines

Ketone-blocked poly amines. These curing agents are complexes of primary aliphatic polyamines with ketone solvents (Figure 2.11). They are also called ketimines . When mixed with the DGEBA they provide long pot lives (up to 8 h) at room temperature. 

Several articles [7,8] have reported that a persulfate-amine system, particularly persulfate-triethanol amine and persulfate-tetramethylethylenediamine (TMEDA) can be used as redox initiators in aqueous solution polymerization of vinyl monomers. Recently, we studied the effect of various amines on the AAM aqueous solution polymerization and found that not only tertiary amine but also secondary and even primary aliphatic amine and their polyamines can promote the vinyl polymerization as shown in Table 6 [40-42]. 

Primary and secondary aliphatic polyamines These are low viscosity and low cost materials. In general, linear and branched primary and secondary aliphatic... 

Diethylaminopropylamine. Diethylaminopropylamine (DEAPA) is an aliphatic polyamine that is used for curing epoxy adhesives where extended pot lives and low heat exotherms are required. This is a reactive primary amine with two active hydrogens as well as a tertiary amine with catalytic activity. 

Primary and secondary aliphatic polyamines, their derivatives, and modified aliphatic polyamines and aromatic amines react with and cure epoxy resins as indicated earlier. The aliphatic systems usually give adequate cures at room temperature (7 days above 60 F) however, under most conditions aromatic amines are less reactive and require curing temperatures of about 300 F to give optimum cured polymer properties. 

The most widely used epoxy systems are those which are based on pure epoxy resins, hardened with a curing agent. Curing of epoxy resins containing two epoxy groups per molecule can be readily accomplished by the addition of primary polyamines, such as ethylene diamine, diethylene triamine, triethylene tetramine, tetra-ethylene pentamine, etc. Aliphatic polyamines produce cured resins with the greatest chemical resistance. However, these systems have inadequate durability, weather resistance and film-forming properties. They are sensitive to humidity, errors in addition rates are quite possible, and the catalysts are relatively toxic. 

When the metal salts dissolve in the aliphatic polyamines containing several primary or secondary amine groups, there takes place the formation of the chelate rings of the types (e.g.. Schemes 33 and 34 [534-537]). 

The most common aliphatic polyamines belong to the homologous series of diethylene triamine (BETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA), which contain both primary and secondary amine groups. 

Multifunctional primary and secondary aliphatic polyamines are used as coreactants. They add readily to the epoxy group at low temperatures to produce highly cross-linked networks. The aromatic amines are somewhat slower than the aliphatic amines, but provide higher heat stability. Examples of amine curatives include diethylenetriamine, triethyl-enetetramine, N-aminoethylpiperazine, and m-phenylenediamine. 

Examples of catalysts are shown on the first line, whereas all the other compounds are coreactants including dicyandiamide, ureas, imidazoles, aliphatic polyamines, cycloaliphatic polyamides, and cycloaliphatic dicarboxylic acid anhydrides. As all the corresponding reaction mechanisms have been previously disclosed in detail," the following presentation is limited to the initial reaction steps leading to the active species involved in the polymerization or polycondensation processes. These primary attacks are enlightened in Fig. 12.6, which displays only one epoxy group reacting with catalysts or coreactants. 

This reaction is reported to proceed at a rapid rate, with over 25% conversion in less than 0.001 s [3]. It can also proceed at very low temperatures, as in the middle of winter. Most primary substituted urea linkages, referred to as urea bonds, are more thermally stable than urethane bonds, by 20-30°C, but not in all cases. Polyamines based on aromatic amines are normally somewhat slower, especially if there are additional electron withdrawing moieties on the aromatic ring, such as chlorine or ester linkages [4]. Use of aliphatic isocyanates, such as methylene bis-4,4 -(cyclohexylisocyanate) (HnMDI), in place of MDI, has been shown to slow the gelation rate to about 60 s, with an amine chain extender present. Sterically hindered secondary amine-terminated polyols, in conjunction with certain aliphatic isocyanates, are reported to have slower gelation times, in some cases as long as 24 h [4]. 

Of the primary monoamines, some, such as. aniline, o-toluidine, xylidine, are colourless liquids. Others, such as p-toluidine, pseudo-cumidine and the naphthylamines, are solids. They can be distilled without decomposition and are volatile with steam. In water they are rather sparingly soluble—a 3 per cent solution of aniline can be made. The di- and polyamines are usually solids, not volatile in steam and much more soluble in water than the monoamines. The amines are basic in character, but, as a result of the negative nature of the phenyl-group, the aromatic amines are considerably weaker bases than are the aliphatic amines. Consequently aqueous solutions of the (stoicheio-metrically) neutral aniline salts are acid to litmus because of the hydrolysis which they undergo. For the same reason a small amount of the free base can be extracted with ether from an aqueous solution of an aniline salt. (Test with a solution of hydrogen chloride in ether or, after evaporation of the ether, by the reaction with bleaching powder.)... 

Amines. Aliphatic mono-, di-, and polyamines derived from fatty and main acids make up this class of surfactants. Primary, secondary, and tertiary monoamines with Qg alkyl or alkenyl chains constitute the bulk of diis class. The products are sold as acetates, naphdienales, or oleates. Principal uses are as ore-flotation agents, corrosion inhibitors, dispersing agents, wetting agents for asphalt, and as intermediates for the production of more highly substituted derivatives... 

Primary and secondary di- and polyamines are used as chain extenders and cross-linkers. Aromatic amines are more reactive than aliphatic ones. 

NIPU networks are created by the reaction between polycyclic carbonate oligomers and aliphatic or cycloaliphatic polyamines with primary amino groups [4], This forms a cross-linked polymer with p-hydroxy urethane groups of a different structure—polyhydroxyurethane polymer. Since NIPU is obtained without using highly toxic isocyanates, the process of synthesis is relatively safe for both humans and the environment in comparison to the production of conventional polyurethanes. Moreover, NIPU is not sensitive to moisture in the surrounding environment. 

Nonetheless, for the more than 50 years since the first publication in this field, NIPUs still do not have sufficiently broad application. This can be explained by certain features of these materials. Cyclic carbonate (CC) groups interact with aliphatic and cycloaliphatic polyamines at ambient temperatures more slowly than isocyanates with hydroxyl groups. The rate of this reaction is comparable to the rate of curing epoxy resins (ER) with amines. At the same time, the CCs react only with primary amino groups, in contrast to the ERs, which react with primary and with secondary amino groups. This results in a decrease in cross-linking density of the polymer network. 

A second important group of starters used in the synthesis of polyether polyols for rigid PU foams is the group of polyamines, aliphatic or aromatic, having 2-3 amino groups/mol (primary or secondary amino groups) such as ethylenediamine (EDA), diethylenetriamine (DETA), ortho-toluene diamine (o-TDA) and diphenylmethanediamine (MDA) [1,2] (see Chapter 4.2). The main properties of these polyamines which are of interest in polyurethane chemistry are presented in Table 13.2. 

P, primary amine S, secondary amine T, tertiary amine A, ammonia N, nitrosamine AA, aromatic amine PA, polyamine Al, aliphatic amine A, air H, water S, soil W, waste. 

In addition to primary polyamines, secondary and tertiary amines are also utilized. The tertiary amines, such as methylated aliphatic aromatic amines,are most commonly utilized. They can best be described as catalysts, rather than hardeners, since they speed up a reaction and contribute to cross-linking, rather than entering into the reaction itself. 

Recently we succeeded in preparing rather large quantities of a primary amine-bearing aliphatic polyester derived from L- and DL-serine, namely poly(amino serinate) or PAS. This polyamine is a potential carrier for oligonucleotides and DNA fragments. It enabled us to make bioresorbable polyelectrolyte complexes where drugs could be easily entrapped for sometime . 

The initial step in the fabrication of a multiple emulsion (W/OAV) is to prepare a primary emulsion (W/0). It is generally agreed that the surfactant for the primary emulsion should have an HLB value of 3-6 (in the hydrophilic-lipophilic balance system of surfactant classification). Surfactants that have successfully been utilized include Span 80 (sorbitan oleate Nianxi et al, 1992 Zheng et al, 1993 Omotosho et al, 1990), E644 (polyamine Nianxieia/., 1992),N205 (polyamine Nianxi eta/., 1992), TX-4 (polyoxyethylene aUcylphenol ether Nianxi et al, 1992), MO A3 (polyoxyethylene aliphatic alcohol ether Nianxi et al, 1992), Brij 93 (Nianxi et al, 1992), polyoxamers [poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer Law et al, 19861, and egg lecithin. The surfactant or combination of surfactants is then dissolved in the oil... 

Aliphatic amines are classified in primary amines (RNH2), secondary amines (R2NH), and tertiary amines (R3N), with R representing in this very general scheme an alkyl chain of any length and further functionalization. Technically interesting classes of amines are shortalkyl amines (primary, secondary, and tertiary), fatty amines, di- and polyamines, as well as aromatic amines. Table 5.3.8 highlights... 

Primary aromatic, and the more difficult to oxidize aliphatic amines, can be converted to their respective nitro derivatives, although NaF has to be added to the more basic aliphatic substrates in order to absorb some of the HF present in the reagent solution. Polyamines such as 2-aminoaniline and other similar derivatives, and sensitive ones such as the bicyclic mirtanyl amine, were also converted to the corresponding nitro derivatives in high yields (eqs 27-29). 

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