Scientists in New York are reporting development of a new biodegradable “nanohybrid” plastic that can be engineered to decompose much faster than existing plastics used in everything from soft drink bottles to medical implants. The study is scheduled for the Nov. issue of ACS’ Biomacromolecules.

The plastic is a modified form of polyhydroxybutyrate (PHB), a promising biodegradable plastic produced from bacteria that has been widely hailed as a “green” alternative to petroleum-based plastic for use in packaging, agricultural and biomedical applications. Although commercially available since the 1980s, PHB has seen only limited use because of its brittleness and unpredictable biodegradation rates.

In the new study, Emmanuel P. Giannelis and colleagues compared the strength and biodegradation rates of raw PHB to a modified form of PHB that contains nanoparticles of clay or “nanoclays.” The scientists found that the modified PHB was stronger and decomposed faster than regular PHB. The nanohybrid PHB decomposed almost completely after seven weeks, while its traditional counterpart showed almost no decomposition. Researchers also showed that degradation could be fine-tuned by adjusting the amount of nanoparticles added.

The study is the “first report of the biodegradation of PHB nanocomposites” and could lead to wider use of PHB plastics, the scientists say.

ARTICLE: "New Biodegradable Polyhydroxybutyrate/Layered Silicate Nanocomposites", http://pubs.acs.org/cgi-bin/sample.cgi/bomaf6/2007/8/i11/html/bm700500t....