Nonreactive polyamides

The most important coating appHcation for the nonreactive polyamide resins is in producing thixotropy. Typical coating resins such as alkyds, modified alkyds, natural and synthetic ester oils, varnishes, and natural vegetable oils can be made thixotropic by the addition of dimer acid-based polyamide resins (see Alkyd resins). Specialty high performance coating appHcations often requite the properties imparted by dimer acid components. 

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. 

The condensation reaction of dimer acid with diamines (like ethylenediamine, hexamethylenediamine, dimer diamine, or others) depending on the molar ratio of the reactants results in acid-terminated, amine-terminated or balanced polyamide resins (Figure 3B.20). They are called nonreactive polyamides because the... 

Another method of achieving the desired molecular weight is by addition of a small amount of a monofunctional monomer. The monofunctional monomer limits the polymerization of bifunctional monomers because its reaction with a growing polymer chain produces chain end devoid of a functional group and hence incapable of further reaction. For example, the use of benzoic acid in reaction (5.5) yields a polyamide (VIII) with nonreactive phenyl end groups thereby limiting the polymerization ... 

In most engineering thermoplastics, from polyamide (PA) to polypropylene (P P) and thermoplastic olefins, the incorporation of coupling agents preapplied onto wollastonite has become prevalent. The development and selection of these coupling agents for both thermoplastic and thermoset composites can include reactive or nonreactive silanes. There are examples of the use oftitanates as surface... 

The primary chemical classes from which adhesives are made include epoxies, acrylics, phenolics, urethanes, natural and synthetic elastomers, amino resins, silicones, polyesters, polyamides, aromatic polyheterocyclics, and the various natural products such as carbohydrates and their derivatives as well as plant- and animal-based proteins. Chemical class was once a relatively clean differentiator of adhesives, but so many adhesives now are hybrids, designed to take advantage of specific attributes of more than one chemical class or type of material. Hybridization can be accomplished by incorporating into an adhesive a nonreactive resin of a different chemical class adding another type of reactive monomer, oligomer,... 

---