Amine terminated nylons

The molecules able to be efficient H-atom donors to alkyl radicals are not restricted to hindered phenols. It has long been noted in the rubber industry that secondary aromatic amines are effective radical scavengers, and study of these materials has shown that they produce a range of coupling products that function in a way similar to the phenols. The problem of the intense colour of these by-products is limited when they are used in carbon-black-filled rubber but a major limitation in other polymers (Zweifel, 1998). The exceptions are the polyamides, in which aromatic amines have a greater stabilization efficiency than do hindered phenols. This may be related to the general observation in polyamides (e.g. nylon-6) that the amine-terminated polymer is more stable than the carboxylic acid-or methyl- terminated polymer. 

Combinations of carboxyl-, vinyl-, and amine-terminated liquid nitrile materials in conjunction with an epoxy resin have been described as an excellent adhesive for bonding various fabrics. A formulation for bonding nylon fabric is shown in Table 27. 

The diamine-terminated nylon 6/66 copolyamide oligomers (CPA, Scheme 6), having the values shown in Table 7 were synthesized by the melt polycondensation reaction of e-caprolactam (CA), adipic acid (AA), and hexamethylene diamine (HA) [37,39]. An excess of HA over AA was used to obtain CPA with terminal amine groups and the molecular weight was controlled by a stoichiometric imbalance of reactants, ie., by varying the AA/HA feed molar ratio at a fixed CA/AA feed molar ratio (Table 7). The diamine-terminated nylon 6... 

Cotton is pure cellulose. Nylon is a polyamide and made by polymerizing adipic acid and hexamethylenediamine. The nylon polymer chain can be prepared with one acid and one amine group at the termini, or with both acids or both amines. Except for these terminal groups, there are no polar centers in nylon and consequently it is difficult to dye. Similarly Dacron, a polyester made by polymerizing ethylene glycol and terephthalic... 

When nylon 6 is heated for 100 h at 305""C, half of the nitrogen escapes from the polymer and a small amount of carbon dioxide forms [457]. This was postulated by Kamerbeek et al. as being the result of reactions of two terminal amine groups [579] ... 

Amine end group n. The terminating (-NH2) group of a nylon polymer chain. Amine end groups provide dye sites for polyamides. 

The chemistry of the production of polyamide resin is very similar to the original process by which nylon was produced. In the Nylon 66 process a dicarboxylic acid, such as adipic acid is reacted with a six carbon amine, for example hexamethylene-diamine, to produce a synthetic fiber In the case of polyamide resin, a dicarboxylic add is reacted or condensed with an amine such as diethylenetriamine to form an amino polyamide. The secondary amine groups of this water soluble polymer are then reacted with epichlorohydrin to form the aminopolyamide epichlorohydrin intermediate. This is then crosslinked to build molecular weight whilst maintaining solubility. The polymerization reaction is terminated by dilution and acidification. 

The first step in making dyadic nylons is the formation of a salt of amine and acid (without condensation). The second step involves actual polycondensation [5]. In a batch process, salt solution is concentrated to about 75% solids before being charged along with a chain terminator such as acetic acid into an autoclave, whereas residence time of several hours and a temperature of up to 280°C yield a polymer with a molecular weight of 12 x 10 -15 x 10. A continuous process for nylon 6,6 was described in Section 5.2. 

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