What Are Polymer Clay Nanocomposites?

Polymer clay nanocomposites are materials made by synthesizing polymers, such as plastics, with clay nanoparticles. This process produces a material that blends the properties of these two substances in new ways. Nanocomposites have distinct properties that are unique to their composition, and the field of nanoscience produces them in order to make materials more useful. For instance, polymers blended with clay nanoparticles dispersed throughout their structure have been shown to have high flame resistance. This development has the potential to improve on flame-retardant products already on the market.

Regular composites are usually made up of bulk polymer with the introduction of a second filler material and a third interfacial material, which assists the first two material components in bonding together. These composites tend, however, to produce weak bonds. In polymer clay nanocomposites on the nano scale, filler material only needs to be one to five percent of the total volume of the materials. When evenly dispersed throughout the host polymer, it turns the polymer into its own interfacial component and causes a magnification of the properties of each. Effective design of polymer clay nanocomposites includes careful choices of organic clays and polymers, and the optimization of the synthesizing process to deliver the biggest benefit.

There are several layered mineral silicates typically used in producing polymer clay nanocomposites. Some are strictly organic clays, and others are modified or combined organic/inorganic clays, manipulated to produce good nanomaterials. Of the clays that have been cleared by the Food and Drug Administration (FDA) — such as montmorillonite and bentonite — prior research has produced knowledge of the results they produce, their effectiveness in reducing gas and oxygen absorption, and their approved use as drug delivery systems or food and drink containers. In its natural state, montmorillonite is hydrophilic, meaning its molecules dissolve easily in water, making it easy to blend with a water-soluble polymer such as vinyl alcohol. When the polymer clay nanocomposite desired includes combining with a non-soluble polymer, the modified montmorillonite that has been rendered hydrophobic in modification might be the clay choice.

Polymers that have been combined with clays are changed in several ways. Their barrier properties are strengthened in impact strength, and mechanically they have more elasticity. Additionally, polymer clay nanocomposites are not as permeable to gases and show more thermal stability under high-heat conditions. The thermoplastics industry uses polymer clay nanocomposites to strengthen industrial belts and produce polypropylene bags that can hold tremendous weight without bursting. In a far different application, polyethylene terephthalate (PET), a polymer clay nanocomposite thermoplastic resin, is used to produce the soft drink bottles one can see lining grocery shelves.