Fantastic plastic

04/20/2007
By From Mass High Tech

by Jay Rizoli, Special to Mass High Tech

If "The Graduate" protagonist Ben Braddock were getting career advice today, it's likely he would hear not just one word, but two: "green plastics."

That seeming oxymoron -- plastics hardly have a reputation as environmentally friendly -- is all the rage in a time of increasing environmental sensitivity, global warming and concern over foreign-oil dependence. Today the shift is on to degradable plastics made not from petrochemicals but from renewable materials such as wood, cotton, corn and milk.

Such technologies were on display April 17 and 18 when the University of Massachusetts Lowell and The Plastics Institute of America held a conference titled "Sustainable Materials Conference: Green Plastics Manufacturing" to help companies explore the shift to making green plastics.

"Plastics from renewable resources is really hot," said Steve McCarthy, director of the Institute for Plastics Innovation in Lowell, who points out that green plastics represent less than 5 percent of the market "but has a lot of potential for growth."

Materials cost is moving in the right direction for growth to occur, McCarthy added. "One thing, recently, is that the price and properties have come down, and that's a huge step because it has to be affordable."

Ironically, what's new is actually old -- some of the first plastics developed in the 19th century were cellulose products derived from wood. Leading the way today are natural plastics made from plant sugars and oils. Made by companies such as Metabolix Inc. in Cambridge, such materials can be found in cups, plates, coatings, adhesives, personal-hygiene products and more.

Beyond the issue of green source materials is biodegradable plastic -- polymers that convert to natural waste products when disposed in biologically active environments and don't adversely affect the environment -- which has been a focus of the 15-year-old Biodegradable Polymer Research Center at UMass Lowell.

"If it's a plant-based plastic, when it degrades in a landfill it turns to CO2 and water," says Eric Hudson, president of Recycline Inc. in Waltham. "You can put a degrading agent into ordinary plastics, but then you know what's going into it, but you don't know what's coming out."

Hudson knows a little bit about landfills -- all of his company's products are made from materials that usually end up in one. Recycline produces Preserve brand toothbrushes, razors and tableware, made from recycled polypropylene or "No. 5" plastic. The raw materials are primarily yogurt cups from Londonderry, N.H.-based Stonyfield Farm Inc., which sends him off-spec and discontinued labels the company no longer uses. And Hudson is always prospecting for more.

Recycline is also exploring plant-based biodegradable plastics and expects to launch them later this year, Hudson said.

"To me, that step toward bioplastics is part of a balanced portfolio. It makes green sense anyway, plus you're reducing CO2 and making it biodegradable."

And speaking of biodegradable, the cutting edge of biological environments to break down plastics is right in your own body, in the form of sutures, implants, stents and transdermal drug-delivery systems. In fact, it was the medical field that led the way in such degradables.

"That's where the focus was 15 years ago, in the medical field, because it was expensive but people were willing to pay," McCarthy said. "The implants or sutures work when they need to work and then disappear. It eliminates the need for a second operation. Not to mention that leaving something in the body for 10 to 20 years could cause problems, too."

But that's just one aspect, says UMass Lowell professor Robert Malloy, chair of the school's plastics-engineering program.

"Medical is an area that is absolutely dynamic -- like you wouldn't believe," Malloy said. "Medical devices is almost a subset of the plastics industry. There's a versatility that allows medical devices to be manufactured."

All in all, Malloy says, that versatility, like the industry, never slows down.

"The thing about plastics is, it is kind of a mature industry -- but one that is continuously increasing because there is constant development of new products. Plastics get used more and more because there are always new plastics. New nanoparticulates are available. Almost everything you can think of goes into plastics: reinforcements, lubricants, fragrance, antimicrobials."

Malloy cites nanofillers that are so small they can be added to strengthen clear plastics without affecting the clarity of the material.

"These are uprecedented property combinations that we were unable to achieve before now. And it's all in its infancy. We've opened up the range more than we've ever seen. And that's what plastics are all about -- versatility."