Reactive polyamides

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. 

Els and McGill [48] reported the action of maleic anhydride on polypropylene-polyisoprene blends. A graft copolymer was found in situ through the modifier, which later enhanced the overall performance of the blend. Scott and Macosko [49] studied the reactive and nonreactive compatibilization of nylon-ethylene-propylene rubber blends. The nonreactive polyamide-ethylene propylene blends showed poor interfacial adhesion between the phases. The reactive polyamide-ethylene propylene-maleic anhydride modified blends showed excellent adhesion and much smaller dispersed phase domain size. 

Reactive Polyamide Resins. Reactive polyamide resins are used extensively lu react with epoxy or phenolic resins. The amount used in epoxy applications far exceeds the use with phenolic resins. 

J.H. Fabris, Novel poly(urethane-amide)s from polyurethane prepolymer and reactive polyamide. Preparation and Properties. Adv. Urethane Sci. Technol., 4, 89-111 (1976). 

Reactive polyamides resins are produced by reacting dimer acid with a slight excess of polyamines (diethyl triamine and triethyl tetramine) to produce low-molecular-weight polyamide resins having free amino groups in the chain (Kale et al., 1994). 

Kale, V. H.S. Vedanayagam R. Subbarao M.B. Rao. Kinetics of reaction of C36 dimet acids with diethylenetriamine and triethylenetetramine for reactive polyamides. /. Appl. Polym. Sci. 1994, 53, 807-814. 

Uses Surfactant for industrial applies., lubricants in prod, ot solid and liq. reactive polyamide resin compositions for crosslinking polyesters to enhance toughness and flexibility defoamer in food-contact coatings, paper/paperboard food pkg. adhesives, coatings, paper, cellophane, polymers... 

Chem. Descrip. Reactive polyamide (condensation prod, of polymerized fatty acids with polyalkyl polyamines)... 

The Cg, Cio and C12 dibasic acids, as their butyl, hexyl, 2-ethylhexyl and octyl esters, are used as plasticizers for PVC, as engine lubricants and as intermediates in the production of polyamides, polyesters and polyurethane adhesives, coatings, fibres, inks and resins. The C2i-diacid is used primarily as a surfactant. By condensation with diamines, dimer acids are used extensively to furnish polyamide resins. Their major applications are printing inks, hot-melt adhesives and coatings. Reactive polyamides are used as curing agents for epoxy resins. 

Dimer acids are used mainly as polyamides. Non-reactive polyamides, produced from dimer acids and diamines in stoichiometric amounts, are flexible and tough and have excellent adhesive properties. They are used as shoe adhesives, in printing inks, for surface coatings and in textile applications. Reactive polyamides, with free amine groups which can react further, are used as components of thermosetting epoxy systems in surface coatings. 

Figure 2.49 Representative structure of reactive polyamide resin...

Non-reactive polyamide (thermoplastic) resins are higher MW (up to 10,000 g/mol) condensation products of dimer fatty acids and diamines. Such resins are important binders for liquid inks. In the synthesis of these resins, both dibasic acid and diamine components are blended at medium temperatures and reacted until the water of reaction can be distilled off. They are solid umber colored products... 

---