Polymer nanocomposites - generally a polymer containing modified nanoclay additives have been used commercially for a few years in niche applications. Automakers now see strong promise in polymer clay nanocomposites especially in polypropylene (PP)/Thermoplastic polyolefin (TPO)/Nylon based nanocomposites. The 1st practical example of polymeric nanocomposites for automotive applications is nylon 6 - clay used to make a timing-belt cover by the Toyota Motor Company. General Motors recently launched a production part, "step-assist" for 2002 GMC Safari - - as the first exterior application. FORD is also active in finding polymer-clay nanocomposites in its auto parts use. Nanocomposites are lighter than metals and filled composites - - thus main motivation for large fuel and energy savings in transportation. True nanocomposites exhibit improved stiffness/strength without sacrifice of toughness besides showing much reduced gas permeability (improved barrier properties), lower coefficient of thermal expansion and improved heat deflection temperature. All the above-mentioned nanocomposites are based on clay and petroleum-based nonbiodegradable polymers. There is a growing urgency to develop novel biobased products and innovative technologies that can reduce the US dependence on fossil fuel and save our precious environment. Green/biobased nanocomposites are the next generation of materials for the future. Renewable resource-based biodegradable polymers including cellulosic plastic (plastic made from tree/wood), polylactic acid, PLA (Corn-derived plastic) and Polyhydroxyalkanoate, PHA (Bacterial polyesters) are some the potential biopolymers which on effective reinforcement with nanoclay can generate so called "green" nanocomposites for automotive applications. However such newly developing green nanocomposites need to be "sustainable" to compete with existing petroleum-based polymer clay nanocomposites. Green nanocomposites derived from renewable resources, having recycling capability and triggered biodegradability (i.e. stable in their intended lifetime but would biodegrade after disposal) with commercial viability and environmental acceptability are termed as "sustainable".
展开▼
