DPI - TUD Colloquium
April 2nd, 2008
Lecturer: John W. Connell, Ph.D NASA Langley Research Center, Hampton, VA 23692
Title: High Temperature Thermosetting Composite Matrix Resins: Phenylethynyl Terminated Imides
Phenylethynyl terminated imide (PETI) oligomers have received considerable attention as matrix resins for high temperature composites. The High Speed Civil Transport Program, conducted in the 1990s, invested significant resources to advance this technology providing the necessary knowledge base, experience and confidence for these materials as high temperature matrix resins. PETI materials provide an excellent combination of properties which include processability, mechanical performance in composites, toughness, microcrack resistance, solvent and moisture resistance and cost.
The approach allows for the use of controlled molecular weight oligomers that exhibit a good processing window, and after consolidation the phenylethynyl groups react thermally without volatile evolution. The cure of the phenylethynyl groups is typically conducted for 1-2 hours at 3710C (7000F). Depending on the application, a post cure of 6-12 hours at 350-4000C may also be used. The thermal reaction of the phenylethynyl groups gives rise to a combination of chain extension, crosslinking and branching. PETI prepreg systems consisting of either a mixture of monomers in alcohol or an amide acid oligomer in polar aprotic solvent such as NMP have been commercialized. Fully imidized PETI systems processable by high temperature resin transfer molding (RTM) or resin infusion (RI) have also been developed.
Recent developments have focused on maximizing the use temperature while maintaining or improving the processing characteristics. The chemistry, physical and mechanical properties of representative PETI materials will be presented.
John W. Connell, Ph.D.
John W. Connell is a senior scientist in the Advanced Materials and Processing Branch at the NASA Langley Research Center in Hampton, VA. His background covers a broad range of advanced materials issues including chemistry, characterization, and processing of high temperature polymers and composites, and space environmentally durable materials. He received B.S. (Chemistry) and Ph.D. (Organic/Polymer Chemistry) degrees from Virginia Commonwealth University in 1982 and 1986, respectively. He is the author or coauthor of over 90 reviewed journal articles, over 100 other referenceable publications (conference proceedings), over 35 U.S. Patents, 3 book chapters, 1 book and Editor of two Special Edition Journal Issues. More than seven of his patents have been licensed to US and foreign companies and developed into commercial products. He has received several NASA awards including the prestigious Medal for Exceptional Scientific Achievement in 1997, Richard T. Whitcomb Aerospace Technology Transfer Awards in 1998, 2001 and 2004, the Turning Goals into Reality Award in 1998 and co-inventor of the year at NASA Langley in 1994. He is presently the Editor-in-Chief of the High Performance Polymers Journal and is a Fellow of the Institute of Physics and the Society for the Advancement of Material and Process Engineering (SAMPE).
Contact: Theo Dingemans or Judith Tesser,
Event location:
TU Delft, Delft Chemtech
Faculty Room, Julianalaan 136, Delft
Fee: free
Registration: no
