Polycaprolactam plastic

Nylons based on oj-aminocarboxylie acids, although briefly investigated by Carothers, were commercialized first in Germany around 1939 (Figure 1). Of particular interest to the plastic industry is nylon 6 (based on caprolactam), which became available in 19A6 in Europe. It was initially Introduced to the United States in 195A by Allied Chemical Company for fiber purposes. Polycaprolactam is crystalline, has a lower melting point than nylon... 

Although synthetic fibers and synthetic elastomers have the same chemical structure as plastics, they are not included among the latter group. Their identification will therefore be treated in this book only if they also occur as plastics. For example, polycaprolactam (Nylon 6) is used both for fiber production and as a molding material (see Sections 6.2.10 and 6.2.20). 

In the course of formation of polymers, some monomer remains in the cured adhesive. This monomer can diffuse to the boundary, plasticizing faulty surface layers of the polymer and adsorbing on the substrate surface [13]. Monomer at the boundary between the adhesive and the substrate inevitably decreases the adhesion strength. For example, by electron microscopy one can observe single crystals of caprolactam on the surface of PC-4 polycaprolactam [14], Removal of the polymer surface layer usually results in noticeable increase of the adhesion strength in the course of bonding [15],... 

Carbon nanotubes are being increasingly used for the reinforcement of plastics, including epoxy resins [57-59], polyamides [55, 60-62], polyimides [63], poly-silsesquioxane [64], polycaprolactam [65], polyethylene oxide [66], polyethylene [67, 55,62], polyurethane [67], ethylene-vinyl acetate [69-73], polyhydroxybutylene-co-hydroxyvalerate [75], ethylene-propylene diene terpolymer [73], and sulfonated polyarylene sulfone [53]. 

Prediction of the adsorption behaviour of the plastics encountered in pharmacy is often difficult because of the complex nature of commercial plastics. Several authors have consequently chosen to examine polymers of known composition such as nylon 66 and polyethylene. Nylon 66 (polycaprolactam) is a polyamide with the general formula —(NH—[CH2],— NH—CO—... 

The best known synthetic polyamides are the nylons. The term nylon originally was a trademark for the polyamide based on hexamethylene diamine and adipic acid (Table 17.3). Later on it became a generic term. The numerals following the name designate the number of carbon atoms in the chain between successive amide groups. The dyadic nylons have two numbers the first for the diamine and the second for the diacid. Monadic nylons such as polycaprolactam require only one number. Although they have been studied as protein models, the synthetic nylon 2 polymers have not been commercialized as fibers or plastics. While some new polymers have been introduced over the years (nylon 4, nylon 1,1, nylon 1,2), nylon 6,6 and nylon 6 have been produced for a longer time and dominate the markets for synthetic polyamides, especially as fibers. 

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