Which do you prefer, paper or plastic? Natural fibers like cotton and wool, or high-tech synthetics like microfleece?

Either way, you may welcome a new polymer developed by Cargill Dow Polymers. The company, a joint venture between Cargill Inc. and Dow Chemical Company, has developed a technology called NatureWorks^TM to manufacture plastic from plants such as corn or wheat. The polymer, polylactide (PLA), combines the best properties of natural and synthetic substances. Since it’s manufactured from plant sugars, it uses renewable resources and is completely biodegradable. Yet it has the strength, flexibility, and low cost of conventional plastics made from hydrocarbons.

After environmentalists began raising concerns about dwindling supplies of fossil fuels and disappearing landfill space, manufacturers have tried to develop sustainable alternatives to hydrocarbon-based plastics. But previous attempts at creating plant-based plastic have failed to catch on, as the new products were either too expensive or simply inferior to existing materials. In contrast, according to Cargill Dow, PLA compares favorably to traditional plastic in both price and performance.

NatureWorks^TM technology takes plant starches and breaks them down into simple sugars, which are then converted to PLA. The process involves the following steps:

1. Starch is separated from the raw material, such as corn, and processed into unrefined dextrose.
2. The dextrose undergoes fermentation, yielding lactic acid.
3. A special condensation process yields an intermediate product called lactide.
4. The lactide is purified and melted so that it can undergo polymerization and form polylactide.

The end product consists of small pellets, which can vary in weight and crystallinity depending on how they will be used.

The physical properties of PLA make it especially well suited for packaging films such as food wrap, trash bags, and envelope windows. With its insulating abilities and effectiveness in retaining flavor and aroma, it could also find use in fast food cups, ice cream containers, and other food packaging. PLA can also be spun into fibers that combine silky feel with resilience and moisture wicking. Items made from PLA fiber may range from outdoor clothing to carpet to diapers.

Cargill Dow especially promotes the environmentally friendly qualities of PLA. Manufacturing the polymer requires 30 to 50 percent less fossil fuel than does producing conventional plastics. It also releases less carbon dioxide. Most significantly, it is made entirely from renewable resources and is completely biodegradable.

To meet the worldwide demand for PLA, Cargill Dow is building a plant in Blair, Nebraska. Scheduled for completion in late 2001, the facility will have the capacity to produce about 140,000 metric tons of the polymer each year.

Related posts:

1. Nobel Winners Discovered World of Electronic Plastics Look at any electrical cord and you’ll see that it is covered with plastic. Plastic makes an ideal insulator because it’s cheap, [...]...
2. Paint-Free Cars Could Be Wave of the Future What were the most popular car colors in this year? DuPont Corporation, a leading paint manufacturer, reports that silver is the top choice worldwide, followed...