Twenty years of polymer-clay nanocomposites

More than twenty years have passed since we invented PCN. in which only a few wt.-% of silicate is randomly and homogeneously dispersed in the polymer matrix. When molded, these nanocomposites show superior properties compared to those of pristine polymers. The number of papers on PCN has increased rapidly in recent years, reaching over 500 in 2005 alone. Being pioneers of this new technology, we review its history relative to the following epochal events: In 1985 we invented nylon 6-clay hybrid (NCH), the first PCN. In 1989, cars equipped with a NCH part were launched. In 1997, Gilman found revolutionary fire retardancy in NCH. In 1997, a PP-clay nanocomposite was prepared using a compatibilizer. In 1998, a compounding method for producing PCN was completed. In 2002, Haraguchi invented a revolutionary nanocomposite hydrogel. So far, only nylon-clay nanocomposites have been used in practice, but other PCN will become increasingly useful in the future.