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2002 Cooperative Research Award in Polymer Science and Engineering

Sponsored by the Eastman Kokak Company

Prof. Benny Freeman
Prof. Benny Freeman
Dr. Ingo Pinnau
Dr. Ingo Pinnau

Professor Benny Freeman of the Chemical Engineering Department at University of Texas at Austin and Dr. Ingo Pinnau of Membrane Technology and Research (MTR) are winners of the 2002 Award for Cooperative Research in Polymer Science and Engineering presented by the American Chemical Society’s (ACS) Division of Polymeric Materials: Science and Engineering (PMSE). Dr. Brian Benecewicz, Chairman of the PMSE Cooperative Research Award Committee, announced the award, which has been presented annually since 1992, when it was endowed by a gift from the Eastman Kodak Company to PMSE.

Dr. Freeman, Professor of Chemical Engineering at the University of Texas at Austin, and Dr. Pinnau, Principal Scientist at MTR, won the 2002 award based on sustained, significant contributions in the areas of gas, vapor, and liquid separations using polymer and polymer-based membranes. Their pioneering research has identified fundamental limitations of existing membranes and led to new materials that elegantly circumvent these limitations. For example, they identified new polymers and polymer-based nanocomposites that, in contrast to conventional polymer membranes, are much more permeable to larger, more soluble molecules (e.g., n-butane) than to smaller molecules (e.g., methane). Membranes prepared from such polymers enable selective separation of volatile or toxic organic vapors from air gases and removal of condensable hydrocarbons from natural gas for dewpoint and heating value control. They have recently conceived of and reduced to practice the concept of applying thin (<1 µm), nonporous coatings of self-assembled block copolymers to the surface of conventional porous membranes for water treatment. These coatings reduce membrane fouling by more than 90% in some applications, such as purification of oily wastewater. Advanced membranes for drinking water production may also benefit from this approach.

Since 1994, their cooperative research has resulted in more than 25 joint publications, two ACS Symposium Series books, many jointly led conferences and symposia, more than 4 million dollars of Federal research support for cooperative research projects between Professor Freeman and Dr. Pinnau, more than 20 joint oral presentations, and significant advancement of the field of novel separations using polymer membranes. Evaluators of the nomination were impressed by the quality of the scientific contributions and by the breadth of joint activities. Professor Freeman is a recognized leader in the science of small molecule transport in polymers. Fundamental research in his laboratory bears directly upon membranes for liquid, gas, and vapor separations; controlled drug delivery devices and techniques; barrier plastics for food and specialty packaging; monomer and solvent removal from formed polymers; and physical aging of glassy polymeric materials and membranes. The National Science Foundation, National Academy of Engineering, the ALCOA Foundation, and the Japan Society for the Promotion of Science (JSPS) have recognized his research. Dr. Pinnau is an authority on polymer-based membranes for separations applications. He directs the materials and membrane production group at MTR, and he has developed a variety of polymeric, solid polymer electrolyte, metal, and nanocomposite membranes for next-generation separation applications in the chemical, petrochemical, and allied industries. He holds 22 U.S. patents and has been honored three times by his selection to receive a prestigious JSPS Fellowship.

The awards, which each include a $1500 prize, will be presented at PMSE's awards luncheon at the Spring 2002 American Chemical Society meeting in Orlando, Florida.

For more information, contact Brian Benicewicz, Rensselaer Chairman, PMSE Cooperative Research Award Committee

C&EN: Science & Technology: Waterworks

April 9, 2001
Volume 79, Number15
CENEAR 79 15 pp.32-38
ISSN 0010-2347

Research accelerates on advanced water-treatment technologies as their use in purification grows


Conventional water purification is a tried-and-true process that hasn’t changed much in decades: Coagulation and flocculation, sedimentation, sand or gravel filtration, and chlorine disinfection are the customary steps. Wresting fresh water from seawater is also a long-standing technique, especially in oil-rich, water-starved countries where the cost of the energy-intensive process is not an issue.

Read more

CNN Sci-Tech: New plastics may keep soft drinks from falling flat

February 6, 1997
From Correspondent David George

RALEIGH, North Carolina (CNN) — Ever wonder why soft drinks sometimes go flat even before you’ve opened the bottle? Ever wonder when somebody’s going to do something about it?

Wonder no more. Researchers at North Carolina State University (NCSU) are experimenting with liquid crystal polymers they say could be used to make plastic soda bottles and other plastic packaging virtually impervious to gas leakage, thus greatly increasing the “shelf life” of hundreds of products.

Leakage is a universal problem in plastic packaging. Every plastic soda bottle that rolls off a production line, every food product packed in plastic, and every plastic container of any kind on any store shelf anywhere will leak to some degree.

It may not be apparent to the casual observer, but slow, invisible leaks can affect the quality of products.

“Anything we have is vulnerable to some degree to air, the oxygen in the air, loss of flavor, gain of outside odors,” said packaging consultant Aaron Brody.

The problem, NCSU researchers say, is that oxygen and other gasses dissolve into the walls of polymer-based plastic containers much like sugar dissolves in coffee.

Dr. Freeman
Dr. Freeman

“The molecules of water actually dissolve into the body of the polymeric film, and then move through the polymeric film itself,” says Dr. Benny Freeman, one of the researchers trying to solve the problem.
Dr. Freeman speaking about this issue.

Freeman and others are conducting experiments to compare the ability of various liquid crystal polymers to form gas-tight barriers.

Chris McDowell
Chris McDowell

The test involves suspending polymer samples from springs inside gas-filled chambers. The more gas a material absorbs, the heavier it gets, says doctoral candidate Chris McDowell.

Freeman compares the molecules in polymers to logs lined up together to form an oxygen barrier 100 times better than that of today’s soda bottles.

Depending on the outcome of the experiments, the airtight polymers may have other uses. Freeman says the electrical industry is already considering using a sleeve made of liquid crystal polymers to extend the life of underground power cables.

And Brody, co-author of an authoritative book on packaging, says the day may soon come when the public will find even beer packaged in plastic, just like soft drinks.

“We’re converting just about everything else into plastic,” he says, “Why not beer?”

Tomorrow Today examines a new weapon against termites — one that drastically reduces the amount of toxic chemicals needed to control the pests.

Pulse Planet: Barrier Plastics

ambience: soda pouring, fizzing

Anyone who’s ever opened a bottle of soda knows that sound. But why is it that even unopened plastic soda bottles lose their fizz over time? I’m Jim Metzner, and this is the Pulse of the Planet.

“The carbon dioxide that gives soda what people normally associate with as fizz is soluble and will dissolve into the wall of the plastic and be transported through the plastic and escape. In much the same way that air in your tires will eventually escape and the tire pressure goes down with time.”

Benny Freeman is an Associate Professor of chemical engineering at North Carolina State University. He’s been studying the effectiveness of plastic packaging.

“Any plastic will permit leakage of small molecules through the plastic. The current packaging materials for things like soda bottles have leak rates that are acceptable for large sizes, but become unacceptable for smaller size bottles or for applications like beer packaging which are more sensitive to things like oxygen coming in from the outside of the package.”

And that’s why you don’t currently see beer packaged in plastic containers.

“For an application like beer where beer is very very sensitive to even small amounts of oxygen, the major factor limiting the use of plastic packaging for beer is that oxygen from the surrounding atmosphere gets into the package and causes the beer to get stale or taste flat.”

But Professor Freeman and his colleagues are on the track of using new kinds of plastic which form more effective barriers. We’ll hear more in future programs.

Pulse of the Planet is presented by DuPont, makers of better things for better living.

To really hold that fizz

Food for Thought
August 24, 1996

If it sits on the shelf long enough, even an unopened 2-liter bottle of Coca-Cola or Diet Sprite will lose its zesty effervescence. What happens is the pent up carbon dioxide slowly leaks through microscopic holes in the molecular structure of the container’s plastic. Fortunately, not all plastics are as permeable as the inexpensive polyethylene terephthalate (PET) used to make large soft-drink bottles. One novel class of more rigid polyesters appears to offer particular promise for bottled drinks. It develops extraordinary barrier properties after it’s been transformed into a liquid crystal, for example, by heating.
Benny D. Freeman of North Carolina State University began working with these experimental materials 5 years ago under a grant issued jointly by the National Science Foundation and Electric Power Research Institute (EPRI). Initially, his mission was one of basic research: to understand how heat alters the structure and barrier properties of these polyesters.

At room temperature, they’re frozen glasses. On a molecular level, they resemble microscopic pick-up sticks that had been dropped onto a flat surface — splaying into a disordered pile with ends sticking every which way. Between individual sticks are big gaps, ones large enough for a soft drink’s carbonation to slowly sneak through.

Under heating, Freeman has found, this polyester begins to align and order itself into tightly packed rows of parallel sticks — like boxed toothpicks. This structure possesses far smaller holes for carbon dioxide or any other molecules to slip through. In fact, heat treating can improve the barrier properties of the starting polyester 10 to 100 fold (depending on what’s trying to escape). That increase is substantial, Freeman notes, since the plastic had started out about as leaky as the PET used in today’s soft drink bottles.

Prototype underground cable using the novel plastic as a moisture barrier. The plastic is that thick grey-white cylinder surrounding the inner cable wires. Credit: Raloff
Prototype underground cable using the novel plastic as a moisture barrier. The plastic is that thick grey-white cylinder surrounding the inner cable wires. Credit: Raloff

Based on Freeman’s findings and EPRI’s financing, a small company in Waltham, Mass., is already developing one such experimental liquid crystal polymer into a superior moisture guard for underground electric cables (above, right). Though these designer plastics are expensive — typically about $10 to $15 per pound, so little is needed that they’re expected to add no more than perhaps a penny per foot to the cost of cable that now runs about $1.25 per foot.

If the new cable sheathing becomes commercially successful, Freeman says, “that single application would double the worldwide market for liquid crystal polymers to about 20 million pounds per year.” Such a dramatic increase in demand for this plastic should also bring down its cost, making it more attractive to bottlers of carbonated beverages, including many who eschew plastics today.

For instance, commercial plastics are so permeable to oxygen, which can destroy the taste of beer, that brewers have generally stuck to glass and metal. Liquid-crystal polyester bottles should preserve the flavor of your ale or lager far longer — though still not as long as glass.

Or consider juice purveyors. Limonene and many other trace flavorants in fruit juices and soft drinks can migrate into PET and other conventional packaging plastics. Not only can this change a drink’s taste, but if the plastic were later reused for some other application, it could shed those trace contaminants into other foods or materials where they might not be appreciated. Liquid crystal polymers appear to make such good barriers, Freeman says, that they could seal in or out any possible adulterants far better than today’s commercial plastics — though, again, not quite as well as glass.

In fact, where bottlers want to sterilize and reuse containers, these experimental polyesters might well stand in for glass, offering the convenience of no breakage and lighter weight.

Heat-transformed plastic, now a liquid crystal, as viewed through an optical microscope. Crossed polarizing filters bring out the colors and patterns in this plastic. Credit: Freeman, N.C. State Univ.
Heat-transformed plastic, now a liquid crystal, as viewed through an optical microscope. Crossed polarizing filters bring out the colors and patterns in this plastic. Credit: Freeman, N.C. State Univ.

While it might be fun to imagine these bottles changing colors, like mood rings of yore (photos, above), bottlers will probably opt for a more prosaic clear or milky opaque form. Indeed, Freeman points out, the liquid crystalline materials in watch faces and some toys change their hue only after they have been sandwiched between two sheets of polarized film and then subjected to a force that temporarily imposes order onto their normally amorphous rod-like structure.


McDowell, C.C., H.C. Shen, and B.D. Freeman. 1966. Thermal transitions and structure evolution in PICT, a soluble nematic LCP exhibiting a kinetically trapped, disordered structure. American Chemical Society annual meeting (polymer division), New Orleans.

Benny D. Freeman, Department of Chemical Engineering, North Carolina State University, Raleigh, NC 27695-7905.

This week’s Food for Thought is prepared by Janet Raloff, senior editor of Science News.

Experimental Plastic Could Keep Soda Fizz From Fizzling

Associated Press Writer

Raleigh (AP) – Does your soda go flat? Is the gas tank on your car corroding? Are your wine bottles to heavy?

If so, researchers at North Carolina State University may have the solution to your problems.

Chemical engineers at the school are working on a strain of liquid crystalline polymer plastic that could seal in flavor and carbonation while keeping out air. The plastic could also be used to stop corrosion of fuel tanks and underground power lines.

“The main science behind it is these polymer molecules pack very well,” said Chris McDowell, a doctoral student working on the project. “The molecules are long and stiff like a pen. That allows them pack together so there is no room for small molecules like oxygen to pass through.”

Beer and wine are extremely sensitive to oxygen and quickly lose their flavor if air gets into the packaging. But the new variety of plastic, known as PICT, could keep enough oxygen out to make plastic beer and wine containers practical.

The plastic also could be used to extend the shelf life of bottled soda, which now keeps for six to eight weeks, and to make smaller, 12-ounce, soda bottles. Existing plastic bottles, which are made from another kind of plastic called PET, can be used to hold only 16 or more ounces of soda.

“Due to how fast these small molecules migrate through PET polymers, you cannot have small packages, ” McDowell explained. “It has to do with the amount of surface area in the smaller packages.”

Dr. Benny Freeman, associate professor of chemical engineering, presented the team’s findings Monday at the American Chemical Society’s annual meeting in New Orleans.

Researchers are uncertain how long commercial development of their plastics might take, but estimate the new food bottles could appear on store shelves within the next decade. The process is expensive now, but Freeman believes his group’s work will pave the way for cost-effective production of food containers and specially coated underground cables.

“Underground electric power cables with a thin coating of these plastics would have substantially longer lifetimes than non-coated cables because of the prevention of moisture ingress and subsequent corrosion,” Freeman said. “Yet adding the coating only adds about one cent per foot to the total production cost.”

Freeman also hopes the plastic will be used to make lightweight, corrosion resistant fuel tanks for cars running on reformulated gasoline.

The project is currently funded by the National Science Foundation and the chemical company Hoechst Celanese.

2011 Student Poster Winners

Congratulations to those who won student poster prizes at the North American Membrane Society (NAMS) meeting 2011 in Las Vegas:

1. Norman Horn, First Place, Gas Separations
2. Dan Miller, Second Place, Liquid Separations
3. Wei Xie, Second Place, Membrane Materials and Formation