Synthesis of nylon 6-clay hybrid
- PDF / 559,668 Bytes
- 6 Pages / 612 x 828 pts Page_size
- 81 Downloads / 199 Views
It was found that montmorillonite cation exchanged for 12-aminolauric acid (12-montmorillonite) was swollen by e-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 e-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 ( - N H 3 + ) 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.
I. INTRODUCTION It is well known that montmorillonite, one of the layered clay minerals, is composed of silicate layers with a thickness of 1 nm. Organic ammonium ions and neutral organic molecules are intercalated in the interlayer space between the silicate layers. Many experiments have been reported on the syntheses of polymers such as polystyrene,1-2 polyacrylic acid,3 and polyacrylonitrile4 in the interlayer space of clay. Although the structure and morphology of the polymers become planar in the interspace of the clay, the mechanical and thermal properties of these materials have hardly been improved. In the preceding paper,5 we reported the swelling behavior of the ion-exchanged montmorillonite with ecaprolactam, which suggested that the interlayer space had the possibility to be a catalyst for ring-opening polymerization of e-caprolactam. If the molecular dispersion is achieved, the mechanical properties of these polymers would be greatly improved, and some new unexpected features may appear. The materials will be called nylon 6-clay hybrid (termed as NCH). This study is aimed at the synthesis of nylon 6 in the montmorillonite layers, which could provide a new molecular composite, a nylon reinforced by clay mineral. The characteristics of the NCH were also studied from the viewpoint of the end-group analysis of nylon 6.
II. EXPERIMENTAL SECTION A. Materials Natural montmorillonite fractionated from bentonite produced in Yamagata, Japan, with a cation-exchange J. Mater. Res., Vol. 8, No. 5, May 1993
http://journals.cambridge.org
Downloaded: 28 May 2014
capacity of 119 meq/100 g was used. Caprolactam and 12-aminolauric acid were commercially available. B. Cation exchange of montmorillonite In a 1000 ml beaker were placed 24 mmol of 12aminolauric acid, 2.4 ml of concentrated hydrochloric acid, and 200 ml of water. In a blender, 10 g of montmorillonite powder was dispersed in 1000 ml of hot water. The hot solution of the 12-aminolauric acid was added in the dispersion, and this mixture was stirred vigorously for 10 min. The product was filtrated,
Data Loading...
