Science | 18.01.2009
Liquid Wood Is Plastic of Tomorrow, Say Scientists
Plastic was one of the great innovations of the 20th century, but German scientists believe a new invention, liquid wood, could soon supplant the chemical in terms of everyday usefulness.
Though it has proven to be extremely useful in the modern world, plastic still has a number of negative selling points. It is non-biodegradable and can contain carcinogens and other toxic substances that can cause cancer.
It is also based on petroleum, a non-renewable resource that will soon be harder to come by. Increases in the price of crude oil leads to parallel rises in the price of plastics.
But there is a new chemical invention that could do away with these long-standing concerns.
Norbert Eisenreich, a senior researcher and deputy of directors at the Fraunhofer Institute for Chemical Technology (ICT) in Pfinztal, Germany, said his team of scientists have come up with a substance that could replace plastic: Arboform -- basically, liquid wood.
It is derived from wood pulp-based lignin and can be mixed with a number of other materials to create a strong, non-toxic alternative to petroleum-based plastics, Eisenreich said, as reported by DPA news agency.
Paper by-product
Bildunterschrift: Großansicht des Bildes mit der Bildunterschrift: Household items could also be made from Arborform
This begs the question: What exactly is liquid wood?
"The cellulose industry separates wood into its three main components -- lignin, cellulose and hemicellulose," ICT team leader Emilia Regina Inone-Kauffmann told DPA.
"The lignin is not needed in papermaking, however. Our colleagues mix that lignin with fine natural fibers made of wood, hemp or flax and natural additives such as wax. From this, they produce plastic granulate that can be melted and injection-moulded."
The final product can resemble highly polished wood or have a more matted finish and look like the plastic used in most household items.
Reduced sulphur content
Car parts and other durable items made of this bio-plastic already exist, but the chemical hadn't been suitable for household use until now, due to the high content of sulphurous substances used in separating the lignin from the cell fibers.
The German researchers were able to reduce the sulphur content in Arborform by about 90 percent, making it much safer for use in everyday items.
Bolstering Arboform's environmental credentials, Eisenreich's team also discovered that the substance was highly recyclable.
"To find that out, we produced components, broke them up into small pieces, and re-processed the broken pieces -- 10 times in all. We did not detect any change in the material properties of the low-sulphur bio-plastic, so that means it can be recycled," said Inone-Kauffmann.
沒有留言:
張貼留言