Due to their molecular structure, ordered polymers can have many favorable mechanical properties, such as a specific strength and modulus (stiffness) twice that of aluminum. Applications of the polymers can be found in everything from food packaging to aircraft structures. A spinoff company, Superex Polymers, Inc., has been formed to commercialize the technology. The product focus of Superex is in rigid tubing for medical use, high-barrier containers for the food and beverage industry, and circuit board laminates for electronics packaging.
Through BMDO and U.S. Air Force SBIR contracts, Foster-Miller, Inc. (Waltham, MA), has developed manufacturing processes and applications for ordered polymers. Ordered polymers have long stiff molecules that, when processed correctly, form a self-reinforced microstructure of fibrils. This microstructure is analogous to continuous fiber reinforcement, where fibers or fabrics form a matrix that gives a material extra strength and stiffness. The key difference is that the microstructure is inherent to an ordered polymer (a fiber matrix does not need to be added), and the fibrils are 100 to 1,000 times finer than fibers used in continuous fiber reinforcement.
As a result of their molecular structure, ordered polymers have many favorable mechanical properties, such as a specific strength and modulus (stiffness) twice that of aluminum. Other properties include:
low coefficient of thermal expansion
low thermal conductivity
excellent gas barrier properties
low dielectric constant
high dielectric strength
Different processing techniques allow researchers to precisely control the polymer's strength, stiffness, and coefficient of thermal expansion. In addition, the self-reinforcing fibrils do not experience the microcracking found in fiber composites, and are much thinner (less than 0.05 mm) than fiber composites.
In the BMDO contracts, Foster-Miller, Inc. developed ordered polymer processing technology and applications for the polymers as cryogenic tank liners and space structures.
Foster-Miller, Inc. is further developing processing technology and applications of the polymer in the following areas:
High-barrier containers: Packaging materials for food, pharmaceuticals, and chemicals must severely limit how much oxygen and water vapor can pass through them, or else food may be spoiled, pharmaceuticals may degrade, and dangerous chemicals may pass into the atmosphere. Ordered polymers are about 100 times less permeable to oxygen and water vapor than commonly used polymer packaging materials. Ordered polymer-based packages thus can replace aluminum foil's high-barrier properties with a microwaveable container. Also, ordered polymer-based packages use a single layer of material, while many high-barrier containers use multiple-layer polymers. Unlike multiple-layer polymers, ordered polymer-based monolayers can be recycled for use in high-barrier applications.
Electronics packaging: With a low dielectric constant and a high-dielectric strength, ordered polymers can increase interconnection density in printed circuit boards by a factor of 10 to over 2,500 cm/cm2. Printed circuit boards using ordered polymers can achieve system speeds over 100 MHz.
Aircraft and satellite structures: For structural applications, the ordered polymers can be formed into a honeycomb core. The lightweight (8.63 kg/m3) honeycomb core is ideal for high temperature stability, low coefficient of thermal expansion, and corrosion-free applications. An ordered polymer honeycomb core should be one-half to one-third the weight of polyaramid or aluminum cores of equivalent stiffness.
High-energy density capacitors: The fibril network increases the surface area in which electrical charge can be stored, allowing ordered polymers to be used for high-energy density capacitors. This technology will reduce the size and increase the reliability of many electronic components such as heart pacemakers. Also, high-temperature capacitors made with ordered polymers will be able to withstand the 250°C temperatures of wave soldering.
Cryogenic storage: Low-permeability thin-film liners provide up to 90 percent weight savings over aluminum liners. When used as insulating components and cryogen feed lines, ordered polymers reduce thermal losses through tank fittings and feed lines over 90 percent.
Because ordered polymers have such a wide range of beneficial properties, researchers expect to find more applications as they gain a better understanding of them.
Foster-Miller has received 8 patents for their ordered polymer technology. The company has formed a subsidiary company, Superex Polymer, Inc. (Waltham, MA), to commercialize their ordered polymer technology. Superex Polymer expects to enter strategic alliances with other companies to manufacture and sell products based on the technology. To date, eight companies have invested $1.3 million in ordered polymer research and development at Foster-Miller and Superex, three companies have licensed processing technology, and three more companies are negotiating licenses. Superex is focusing on rigid tubing, high-barrier containers, and circuit board laminates.
Rigid tubing: In late 1995, Superex began selling its liquid crystal polymer (LCP) tubing for endoscopic and laparoscopic applications. The high stiffness and strength of the tubing, coupled with its ability to withstand chemical and thermal sterilization methods, make it ideal for medical use. It also costs 30% less than fiber-reinforced composite tubing, is much lighter than the stainless steel tubing often used in endoscopy and laparoscopy, and is not electrically conductive.
The rigid tubing can be used for cannula/trochar sets—hollow tubes that contain sharp instruments for piercing tissues and gaining access to body cavities. The tubes can also be used as casings for high-voltage electro-surgical pencils (devices that cut and cauterize simultaneously) because of LCP's high electrical insulation properties. The material can also be used for irrigation and aspiration tubing. Superex has entered an agreement with ACT Medical (Waltham, MA), a manufacturer and vendor of custom surgical instruments, to use its LCP material in ACT's products.
High-barrier containers: Traditionally, plastic bottles have been shunned by brewers because their porosity allows beer to go flat and, more importantly, changes its flavor. Addressing these problems, Superex is working in a consortium to develop a multilayer beer bottle that combines polyethylene perephthalate (PET) with LCPs. Superex tests show that in a humid environment the oxygen barrier using LCP is eight-times higher than ethylene vinyl alcohol (EVOH), a widely used barrier material. “A layer of less than 0.0004 inch of LCP can do the same job as 0.002 inch of EVOH”, says Richard Lusignea, Superex’s president. “Because less material is used, the LCP offers a 20 to 30 percent cost savings.” Using thin LCP films, Superex has also developed a line of food containers that are microwavable and shelf stable up to three years.
Circuit board laminates: Circuit-board substrates laminated with thin LCP films represent an annual market estimated at $4.5 billion, according to Superex. The main advantage of LCP is its high moisture barrier, which can be used to seal and protect components. “LCP films absorb 50 to 100 times less moisture than polyimide film,” says a Superex press release, “resulting in much more stable electrical properties in normal and humid environments.” The coefficient of thermal expansion of LCP laminates and circuit boards can be matched to that of silicon chips and chip packages, providing higher reliability than circuit boards made from fiberglass-epoxy or polyimide film.
Collaborating with Brampton Engineering, Inc. (Brampton, Ontario), Superex has scaled up its process for mass production. In one hour, the new equipment can produce up to 8,400 feet2 of biaxially or multiaxially oriented LCP films that are 0.001- to 0.005-inch thick. Superex’s LCP process technology and Brampton Engineering’s equipment are available for licensing and purchase.
Foster-Miller is the largest independently owned equipment development firm in the U.S., with over 40 years of rapidly and successfully completing client-proprietary product, process, and manufacturing development projects. The company has an in-house staff of over 200 engineers and scientists that covers virtually every industry and engineering discipline.
Superex is a related company that provides new technology for processing highly advanced liquid crystal polymer (LCP) products. Because of this versatile and cost-effective processing method, the superior properties of LCPs can now be practically applied in many ways, such as: high barrier films for foods and beverages; substrates for high density multilayer printed circuit boards; high performance tubing; barrier layers for cryogenics; high temperature electrical insulation.
Mr. Richard W. Lusignea
Superex Polymer, Inc.
350 Second Avenue
Waltham MA 02154