ChemWeb Newsletter

Not a subscriber? Join now.March 22, 2005


This week's Alchemist picks up on several stories from the 229th national meeting of the American Chemical Society as well as some fascinating research elsewhere. First, we report on how thicker nanotubes could cut costs and how a benchtop simulation could prove useful in recovering natural gas from the ocean floor. Next up is the fast food additive that could prevent type II diabetes, and the domestic plastics factory. Finally, an artistic sawhorse is broken at last.

The green pigment copper resinate was never used by the Old Masters, according to the latest study by Dutch art historian Margriet van Eikema Hommes. Old paint recipes, investigations of dozens of paintings and experiments to reproduce the green paint failed to show that the likes of Frans Hals, Raphael and Titian used copper resinate. Instead, van Eikema Hommes' careful study shows that the color was produced from finely powdered verdigris mixed with a cold oil or vanish. The myth arose because of confusion with two distinct recipes one for making green pigments for paintings and the other for coloring glass and metal foil.

Jie Liu Liu of Duke University and colleagues have found that single-walled carbon nanotubes (SWNTs), much touted for future sub-microelectronics applications, may not be the best materials for some jobs after all. They have synthesized and studied nanotubes that have two to five cylindrical layers each inside the next that are much easier to make than SWNTs. The team has already patented application of few-walled nanotubes (FWNTs?) to electron field emission.

A simulation of the temperatures and pressures felt on the ocean floor has been demonstrated by researchers from Brookhaven National Laboratory. The experiment is providing data that could help us "mine" the natural gas locked in the depths of the oceans. "The amount of natural gas is tied up in methane hydrates beneath the seafloor and in permafrost on Earth is several orders of magnitude higher than all other known conventional sources of natural gas," explains BNL's Devinder Mahajan, "enough to meet our energy needs for several decades." Extracting this resource poses several challenges but Mahajan and colleague Michael Eaton hope their simulation will provide new information on how that might be achieved.

Hydroxypropylmethylcellulose (HPMC, a form of soluble cellulose already used as a texturizing food additive) could make fat-rich junk food more palatable for the health conscious. According to Wallace Yokoyama of the US Department of Agriculture's Agricultural Research Service, in Albany, California, the compound slows down fat absorption and if it proves effective in humans, could reduce the risk of developing insulin resistance or type II diabetes. Yokoyama warns that while the compound's benefit is in slowing fat absorption and reducing the "insulin spike" triggered by fatty foods. It will not prevent those dining on excess amounts of such foods from gaining weight.

A domestic version of the rapid-prototyping machines available to industry designers could be available in a few years thanks to an innovation by Adrian Bowyer of the University of Bath, UK, and his colleagues. 3D prototyping machines use a computer to controlling the "printing" of a solid object from liquid resin. They allow designers to create facsimiles of their designs in inexpensive resin before a true prototype is constructed from more expensive materials. However, the industrial strength machines cost about $50k making them inaccessible to home users. Bowyer and his colleagues are developing the plans for a smaller scale 3D printer that could itself be "printed" by an industrial model much more cheaply than building a whole new machine from scratch. A domestic version of the machine could be used to make almost any object from a musical recorder to a tea-cup, a plate, a whole plastic dinner service, even!