Novel thermoplastic starch-clay nanocomposite foams
Meng Chen1, Biqiong Chen, Julian R G Evans
1Department of Materials, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
Abstract:
Novel thermoplastic starch (TPS)-clay nanocomposite foams were prepared by melt-processing. The use of urea as plasticizer avoids the cracking of TPS during storage and enhances the dispersion of ammonium-treated clay in TPS. X-ray diffraction shows an increase in the basal plane spacings of both natural and treated clays, suggesting formation of nanocomposites. Scanning electron microscopy shows spontaneously formed regular foam structures with 84% porosity in TPS-ammonium-treated clay. This does not form in TPS or TPS-natural clay nanocomposites. This result implies that the regular foam formation is due to the ammonium surfactant of clay, which produces ammonia gas acting as an internal blowing agent. Thermogravimetric analysis confirms this deduction.
Related Concept Videos
01:08Molecular Weight of Step-Growth Polymers
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
01:30Superplasticizers