High oil and natural gas prices mean the time is ripe for plastics from corn, soybeans or other plants - but that's not always as easy as it sounds, speakers said during an Antec forum on industrial biotechnology.
``Society is asking for more-sustainable materials,'' said Joseph Kurian, research and development manager for DuPont Co.'s Sorona resin. DuPont has partnered with Tate & Lyle PLC of London, a major manufacturer of agricultural products including sugar and syrups.
The venture, DuPont Tate & Lyle BioProducts LLC, will make a corn-based propanediol that will be used to make DuPont's Sorona-brand polymer, at a resin plant in Loudon, Tenn.
Kurian said Sorona applications include fibers such as textiles and carpeting and film for packaging.
The material is made by a fermentiation process - but Kurian said it's not as easy as making beer or wine. The material has to be extremely pure.
All plant-based plastics face the same challenge, Kurian said. Although the technology to make plastic from crops is proven, the plastics must be low-priced and have similar properties to traditional plastics, or face commercial failure, he said.
Attendees at the Society of Plastics Engineers session also heard speakers from Cargill Dow LLC, which uses corn as its primary feedstock to make NatureWorks-brand polylactic acids in Blair, Neb. The biodegradable material goes into fibers and film, rigid containers and bottles. Other speakers from BASF Corp. described that company's biogradable Ecoflex polymer used for trash bags, packaging and agricultural sheeting. Ecoflex is an aliphatic-aromatic copolyester.
The technology forum was kicked off by two professors from Michigan State University in East Lansing, Mich. Lawrence Drzal said certain plants can make reinforcing fibers that compete with glass fibers on price, such as jute, hemp, coconut, pineapple leaf, straw fibers and even some types of wild grasses. These so-called biofibers can be converted from plants at just 25 cents a pound, vs. 70 cents a pound for glass fibers.
``You have a three-to-one [cost] advantage with these materials,'' Drzal said.
It is necessary to blend several different natural fibers to get the proper balance of stiffness and toughness. Materials from plants are obviously more variable than their petroleum-based counterparts. That means designers have to understand the new materials as they create new products.
Ramani Narayan explained ASTM International standard test methods to determine what is a ``bio-based'' material, which must be organic and contain ``new'' carbon. That means carbon from things like crops - as opposed to oil, which contains carbon formed under a geologic time frame.