Journal of Materials Research


Synthesis of nylon 6-clay hybrid

Arimitsu Usukia1, Yoshitsugu Kojimaa1, Masaya Kawasumia1, Akane Okadaa1, Yoshiaki Fukushimaa1, Toshio Kurauchia1 and Osami Kamigaitoa1

a1 Toyota Central Research & Development Labs. Inc., Nagakute-cho, Aichi-gun, Aichi 480-11, Japan


It was found that montmorillonite cation exchanged for 12-aminolauric acid (12-montmorillonite) was swollen by xs220A-caprolactam to form a new intercalated compound. Caprolactam was polymerized in the interlayer of montmorillonite, a layer silicate, yielding a nylon 6-clay hybrid (NCH). The silicate layers of montmorillonite were uniformly dispersed in nylon 6. The carboxyl end groups of 12-aminolauric acid in 12-montmorillonite initiated polymerization of xs220A-caprolactam, and as 12-montmorillonite content became larger, the molecular weight of nylon was reduced. From the result of end-group analysis, carboxyl end groups were more than amino end groups. The difference between the carboxyl and the amino end groups was attributed to ammonium cations (-NH3+) of nylon molecules, because the difference agreed with the anion site concentration of the montmorillonite in NCH. It is suggested that the ammonium cations in nylon 6 interact with the anions in montmorillonite.

(Received January 22 1992)

(Accepted December 31 1992)