Menu
About Science
Study reveals why the leopard got its spots
Allergy risk linked to time of first trimester
Hubble reveals furthest galaxy yet
Scientists confirm water from lunar probe
Researchers power up tiny batteries
Plants clean air better than expected
Haiti fault capable of another big quake
Japanese man joins growing genome ranks
NASA releases report into balloon crash
Tree's ability to soak up CO2 has limits
Ground coffee helps robot get a grip
Assassin bugs lure arachnid snack
Research reveals spring in ostrich's step
Lizard gender bends at altitude
Study suggests early primates out of Asia
Flamingos boost their colour to find a mate
Globular clusters more than one-off event
Ancient Africans first to use sharp tools
Grass could turn toxic waste into energy
Earth-like planets may be common
Natural born cell killers
Fingers spot typo ahead of the brain
Ecofriendly styrofoam from milk and clay
Study proves exercise boosts immune system
Ecofriendly styrofoam from milk and clay
We already have plastics made from corn and sugar. Now, scientists have created a Styrofoam-like material using mostly milk proteins and clay.

Ultra-light and largely biodegradable, the plastic might someday become a green alternative to petroleum-derived foam packaging blocks, among other applications.

"The idea that we could go from milk and dirt to plastic foam seems attractive," says Professor David Schiraldi, a polymer scientist at Case Western Reserve University in Cleveland. "Clay is pretty close to inexhaustible. Our only effluent is water vapor. It seems pretty green to me."

The research began with an accidental discovery in the lab. One of Schiraldi's students freeze-dried clay and got something intriguing enough to warrant a closer look. So, the team started mixing the clay with a variety of materials.

When they added a cow's milk protein called casein, they ended up with a super-light, fluffy, and foam-like material. With further experimentation, they hit on a recipe that worked well enough for publication in the journal Biomacromolecules .

"The process," says Schiraldi, "is simplicity itself."
Blended together

The researchers start by throwing a scoop of clay and some water into a kitchen blender. Two minutes of mixing produces what Schiraldi's students call a clay smoothie.

Next, they add some casein powder, a dried version of the most common protein in milk. The final ingredient is a tiny amount of a glycerol-based material, which basically stiffens up the solution's chemical bonds.

After running the blender one last time, the scientists pour the dirty-looking water into moulds and freeze them like ice-cubes. Then, they freeze-dry it to remove the water.

The result, Schiraldi says, is a material that has all the same properties of Styrofoam, but is 98 percent bio-based. In tests by the US Department of Agriculture, close to a third of the new material broke down after about 45 days in industrial compost conditions. That's a huge environmental leap beyond Styrofoam and other types of expanded polystyrene foam, materials often used as disposable packaging for electronics and other products.

"Compared to expanded polystyrene foam, we're in a different league," says Schiraldi. "Styrofoam lives forever."

The research spawned a brand new start-up company, which is using the patented technology to develop practical products. Schiraldi imagines a plastic factory of the future that taps into vats of milk instead of oil.
Hurdles yet to overcome

Before milk-based plastics will go mainstream, though, there are technological hurdles to overcome. For example, scientists will need to make sure that the new material doesn't smell like sour milk.

There are also practical market pressures to contend with, says Dr James McGrath, a chemical engineer at Virginia Tech in Blacksburg.

"It makes a nice quote to say this is going to replace polystyrene foam, but there are a lot of issues," says McGrath, "including economic ones and the price-to-volume relationship."

"It always looks good to come up with something like this," he says. "It's a very worthwhile objective to pursue."

Print
Researchers put spark into scramjets
Fish found making their own 'mozzie' nets
Japan confirms asteroid dust on outback probe
Genetech pioneer awarded science prize
Scientists capture anti-matter atoms
Study reveals Icelandic eruption build-up
Astronomers spot galactic intruder
Open-mouthed laughter appreciated most
Financial crisis causes dip in CO2 levels
Puberty genes linked to body fat
Face shields needed for combat: study
Organically-grown vegies not more nutritious
Bloodstains could give age away
Models show pterosaurs flew long, slow
Marsupial carnivores were underestimated
Massive black hole collision revealed
Jet-lag causes long term memory loss
Sunken tanks could detect secret nukes
Dino demise supersized the mammals
Binge drinking linked to heart disease
Cassini sniffs oxygen on Saturnian moon
Image shows echoes from before big bang
Research uncovers diamond's soft side
World warmer, but trends at odds: report
Humans caused megafauna demise: expert
The world: Four degrees warmer
Blood vessels show pollution, heart disease link
Young great whites don't have the bite
Menu
Dolphin social network good for calves
Is fish-oil Alzheimer snake-oil?
Cosmic rays trace Sun's journey through space
Marsupial mole mystery solved
Scientists warn of new polio virus strain
Oldest known stone axe found in Arnhem Land
Fly-by captures first comet photos
Dead quasar's ghostly glow reignites debate
Mum and Dad tell us how to wear our genes
New images expand solar flare knowledge
Experts urge caution on Snowy cloud seeding
First little Big Bangs created at CERN
Tarantulas help map the fear factor
Neanderthal brains developed differently
Whales showing more sun damage
Bush cricket has the biggest balls of all
Giant gamma bubbles found in Milky Way
Complex life possible earlier than first thought
Happiness evades wandering minds?
Cat lapping defies gravity
Physics unravels wet dog shake
Hubble captures rare galactic view
Early wrinkles no sign of an early grave
World's forests suffer from 'leakage'