Current ResearchList of Current Research Topics Projects in the Innovative Materials Department
Projects in the Specialty Coatings Department:
High Temperature Sizing For Aerospace Applications Hydrosize® Technologies, Inc. received Phase II funding ($750K/2 years) from the Naval Air Systems Command (NAVAIR) with technical management provided by the Air Force Research Laboratory (AFRL/ML) for the development of a “High Temperature Sizing for Carbon Fiber Reinforced Fluorinated Addition Polyimides”. The main objectives of this project are to develop a sizing that will be thermally stable at the elevated temperature (~371°C) necessary to fabricate and to fully cure the carbon fiber reinforced fluorinated addition polyimide, compatible with the fluorinated addition polyimide resin, and aid in weaving and preform fabrication. Also, the sizing must have long term, high temperature stability (550°F and higher). To be effective, the sizing must be chemically compatible with the resin to improve interfacial properties. The sizing has a chemical composition similar to the matrix resin to promote miscibility and interdiffusion in the interphase region. The polymer sizing was endcapped with a reactive group that may covalently bond with the matrix resin to further enhance the interfacial adhesion. The new sizing was synthesized utilizing a proprietary HydrosizeÒ process developed for the manufacture of Hydrosize’s commercial high temperature sizings, Hydrosize® HP-1632 and Hydrosize® 1621. Therefore, the commercialization of the developmental high temperature sizing will proceed swiftly and efficiently. In collaboration with Professor Lawrence Drzal from the Department of Chemical Engineering and Materials Science at Michigan State University, it was shown in Phase I that the unidirectional composite laminates made with carbon fiber sized with the new Hydrosize sizing exhibited a significant improvement in the interfacial shear strength over the epoxy sized control. This allowed for the extension of the project through Phase II funding. In Phase II, we have manufactured the new sizing to commercial scale, applied the new sizing to the unsized Cytec 3k T650 carbon fiber, and wove the fiber into 36” width fabric. During the sizing trial, the T650 fiber was also sized with Cytec’s HTS sizing on the same equipment. The new sizing showed a significant reduction in fuzz and improved weavability as compared to the Cytec HTS control. Prepreg was produced with this fabric and void free composite laminates have been fabricated. The mechanical properties of the Hydrosize high temperature sizing provided an average of a 20% increase in mechanical properties including a 35% increase in compression strength under hot (500°F)/wet conditions. The composite laminates were then aged at 600°F for 1000 hours. The Hydrosize high temperature sizing provided a 38% increase in the interlaminar shear strength (ILSS) as compared to the HTS control after aging. Furthermore, the new sizing is organic solvent free, nonflammable, contains no hazardous air pollutants, and safe for worker exposure. In addition, the new sizing is compatible with the manufacturing equipment and techniques employed at the fiber production plants. The sizing will be applied during the manufacture of the fiber eliminating any additional off-line processing steps. Hydrosize® Sizings for Vinyl Ester and Unsaturated Polyester Resins With the reduction of carbon fiber prices many new applications are being considered outside the traditional aerospace industry. There is significant growth potential for carbon fiber reinforced vinyl esters (VE) and unsaturated polyesters as seen by the plethora of innovative applications currently under investigation such as automotive, marine, infrastructure, wind energy, and recreational/sports products. However, growth is limited by the relatively poor interface formed between carbon fiber and VE/polyester resins resulting in less than optimal composite performance. Hydrosize® Technologies, Inc. has an ongoing research and development effort focused on improving the interphase. Hydrosize® HP3-01, a waterborne poly(hydroxy ether) sizing, provides significant improvements in key properties as compared to a typical epoxy sizing.
Hydrosize® HP3-02 provides enhanced emulsion stability, processability and handling of the fibers, and composite mechanical properties. The flexural strength was increased by 9% and the flexural modulus by 12% when Hydrosize® HP3-02 was utilized as the sizing in a carbon fiber reinforced vinyl ester composite as compared to Hydrosize® HP3-01. The dedicated team of research scientists is actively pursuing new technologies that will set new standards for SMC, pultrusion, and VARTM processes. The Office of Naval Research has recently awarded Hydrosize® Technologies, Inc. SBIR funding for the “Improved Interface and Mechanical Properties in High Modulus Carbon Fiber Reinforced Vinyl Ester Composite Laminates.” This collaborative effort combines the resources and expertise of Hydrosize®, Virginia Tech, and ONR to develop the next generation of technology for this key market segment. Hydrosize® Melt Processable Reactive Imide Oligomers An extensive knowledge platform has been established on the use of thermosetting imide oligomers for melt processing composite parts. These resins show great promise; however, the high cost and the lack of dedication to commercialize these products has limited their widespread use. Hydrosize® Technologies, Inc. will take what has already been demonstrated, optimize the technology, and use low cost domestically produced, readily available raw materials to bring these ideas to commercial fruition. Characteristics of Hydrosize® Developmental Thermosetting Imide Oligomers
20°C/min in N2; 1st heat to 450°C; temperatures reported in °C
Melt Viscosity as a Function of Temperature Poly(arylene ether sulfone) For Fuel Cell Proton Exchange Membranes For over 40 years, fuel cells have been used as an energy source for spacecraft. Recently, fuel cells have gained considerable interest to provide power for everyday items such as automobiles, homes, and electronics. Fuel cells have the dual advantage of being a “green” resource and providing longer-term energy for portable electronics. Imagine your laptop not only retaining power during a transcontinental flight but for weeks at a time. A major component of a fuel cell is the proton exchange membrane (a polymeric film). The current state of the art commercially available product is Nafion by DuPont. Nafion has several advantageous properties but also has a few shortcomings. Much research has been conducted to find a replacement. A very promising candidate, a novel wholly aromatic poly(arylene ether sulfone) containing pendant sulfonate groups, was developed by McGrath et al. at Virginia Tech. Virginia Tech and the Department of Energy have contracted Hydrosize® Technologies Inc. for the scale up of the syntheses of the novel monomer and the subsequent polymer.
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