Aliphatic polyamine

Depending on the number of amine groups in the molecule, the amine can be a mono-, di-, tri-, or polyamine. Aliphatic amines can also be classified by their molecular structure as linear, branched, aliphatic, or containing aromatic groups. However, the most valuable method of classification is by functionality. 

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. 

Polyamines. Aliphatic polyamines cure epoxy resins via their epoxy groups at ambient temperature. Excess amine is generally prereacted with the epoxy resin to form a polyamine adduct. Amines react with monomeric or dimeric fatty acids to form polyamidoamines. Polyamine-adduct-cured epoxy resins have a high chemical resistance. Polyamidoamine-cured epoxy resins exhibit good adhesion and flexibility. 

Pot life definition (source) 2-part epoxy polyamide 2-part epoxy polyamine (aliphatic) 2-part epoxy polyamine (aromatic) 3-part flexibilised 2-part toughened epoxy polyamine epoxy ... 

The condensation leaves epoxy end groups that are then reacted in a separate step with nucleophilic compounds (alcohols, acids, or amines). Eor use as an adhesive, the epoxy resin and the curing resin (usually an aliphatic polyamine) are packaged separately and mixed together immediately before... 

The aliphatic diamine and polyamine family encompasses a wide range of multiftmctional, multireactive compounds. This family includes etiiylenediamine... 

Table 5. Typical Specifications of Some Aliphatic Polyamines...

Reactive Polyamide Resins. Another significant commercial appHcation of dimer acids is in reactive polyamide resins. These are formed by the reaction of dimer acids with polyamines such as diethylenetriamine to form polyamides containing reactive secondary amine groups (see DiAMlNES AND HIGHER AMINES, aliphatic). In contrast to nonreactive polyamides, these materials are generally Hquids at 25°C. 

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]. 

Aliphatic polyamine disulfides—imino-, carbamide-, thiocarbamide-, ethylenediamine------are low-effi-... 

Polythiosemicarbazide disulfide is the most efficient aliphatic polyamine disulfide for inhibiting the thermal oxidative breakdown of polypropylene, while polyimi-noaniline disulfide and polydiiminodiphenyloxide disulfide (Fig. 3) are the most efficient aromatic polyamine disulfides. In contrast to polyethylene, the thermal oxidative breakdown period increases as the concentration increases (Fig. 4), Depending on the concentration, the flow-melt index at 230°C increases at a lower rate than in the case of commercial stabilizer Santanox (Table 2)-... 

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]. 

Aliphatic polyamines, amine adducts and polyamides react with epoxide resins at normal temperatures to give complexes with outstanding chemical resistance. Paints based on this type of reaction must be supplied in two separate containers, one containing the epoxide resin and the other the curing agent , the two being mixed in prescribed proportions immediately before use. 

The simplest polyamines are the aliphatic types such as diaminoethane, but these readily carbonate when exposed to the atmosphere as a thin him, so adducts (pre-reacted epoxy polyamines) are preferred. An alternative system is the polyaminoamides which are made by reacting dimerised fatty acids with an excess of polyamine. These themselves act as corrosion inhibitors and are noted for excellent adhesion. 

When aliphatic amines come into contact with cellulose nitrate, this gives rise to charring without ignition. If these amines are replaced by polyamines or amino-alcohols, the mixture combusts spontaneously. 

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