Presented January 22, 2015- Presentation Slides
Isocyanate-Free Solid Rocket Motor Propellant Binders Inspired by Nature by Dr. Andrew Guenthner
A new SERDP SEED project is currently demonstrating the feasibility of new isocyanate-free solid rocket motor propellant binder formulations for DoD rocket and missile systems by utilizing chemical functionalities and solidification mechanisms found in safe, environmentally-friendly natural products to replace isocyanate cure. The ultimate aim of the effort is to develop an effective means of cure using a selected chemical functionality and mechanism in an energetic binder formulation with no significant loss in performance and insensitivity compared to state-of-the-art formulations, but with significant reductions in environmental, safety and occupational health risks. The main focus of the SEED project is to mitigate the major technical risks associated with the effort by screening candidate functionalities and validating key aspects of performance. To date, the SEED program has made significant progress in screening candidates, with promising results demonstrated in inert formulations. Preparations for testing in energetic formulations are now underway. If successful, this effort will eliminate a significant source of manufacturing risk for solid rocket motor propellants based on ammonium perchlorate, and may also significantly reduce concerns related to process variability and propellant ageing.
Cyanate Ester Composite Resins Derived from Renewable Polyphenol Sources by Dr. Benjamin Harvey
Composite materials consisting of an organic resin and fiber support are widely used throughout the Department of Defense (DoD). Composites provide a number of performance advantages over conventional materials including a significant reduction in weight which results in reduced fuel usage and/or greater range for military platforms. Unfortunately, these environmental benefits are offset by the non-sustainable derivation of polymer composites from petroleum. This presentation will describe recent efforts to develop full performance thermosetting resins from renewable and sustainable polyphenols that can be prepared from biomass sources including lignin, essential oils, natural turpentine and grape skins. In many cases, the structural diversity of the source materials allows for atom-economic routes to new bisphenols that can be used as precursors to both thermosets and thermoplastics. A variety of new resins have been prepared with performance characteristics (e.g., glass transition temperature, water uptake and thermal stability) comparable to and in some cases exceeding those of conventional petroleum-derived resins. Renewable resins have been synthesized on scales of up to one pound and are currently being formulated into bulk molding compounds that can be used for the fabrication of composite parts to replace heavier metal components.
Environmentally Friendly High Performance Bio-Based Polymers for DoD Applications by Dr. John La Scala
Polymer composite materials are derived from non-renewable petroleum sources, making their use unsustainable and causing their cost to be highly volatile. Furthermore, polymer composite materials often contain toxic components or produce toxic emissions. To address these issues, we have used plant-derived renewable resources to develop a number of polymer composite materials technologies with properties and performance similar to that of petroleum-derived composites. We formulated and developed fatty acid-based vinyl ester resins derived from plant oils and successfully demonstrated and validated them on weapons platforms across the DoD. We chemically modified lignin to produce lignin-based carbon fiber with the highest reported strength and modulus. We have been addressing toxicity issues associated with bisphenol, a component used in the production of many high performance polymers. Through use of polymers from lignin-derived chemicals, such as guaiacol, and carbohydrate-derived isosorbide and furans, we have created a number of polymers with properties similar or superior to that of commercial polymers. Furthermore, we have shown that these bio-based chemicals and polymers have reduced toxicity relative to the baseline commercial polymers. As a result, we are currently preparing diamines derived from carbohydrates and lignin to reduce the toxicity and improve the sustainability of polyimides and epoxies.
Dr. Andrew Guenthner is a Senior Chemical Engineer with the Air Force Research Laboratory’s Rocket Propulsion Division at Edwards AFB, California, a position he has held since 2009. Andrew’s current research includes investigations of the connections between the chemistry and the performance characteristics of materials and interfaces for solid rocket motors including advanced propellant binders. Previously, from 2000 to 2009, Andrew worked as a Materials Engineer at the Naval Air Warfare Center, Weapons Division in China Lake, California, where he also served as the leader of the Polymer Science and Engineering section from 2005 to 2009. Andrew received a Ph.D. in Polymer Engineering from the University of Akron in 2000, and a Bachelor of Science in Chemical Engineering from Case Western Reserve University in 1995. As of December 2014, Andrew has co-authored over 110 publications and has been awarded seven United States patents in the fields of polymer science and surface science.
Dr. Benjamin Harvey is a senior research chemist with the Naval Air Warfare Center, Weapons Division (NAWCWD) in China Lake, CA. Ben’s current research interests include sustainable high temperature composites, atom-economic catalysis and high density renewable fuels. Ben has served as the principal investigator on two SERDP projects focused on renewable polymers, as well as a number of projects related to biosynthetic high-performance fuels, green/sustainable chemistry, nanocomposite materials and catalysis. He is also the Navy lead on a SERDP project that seeks to develop non-toxic methylene dianiline replacements for high temperature polyimides. Ben has authored more than 45 peer-reviewed articles, including several on renewable composite materials, and has been awarded 9 patents. In addition, he is on the editorial advisory board for The Journal of Chemical Technology and Biotechnology. Ben received the 2011 Dr. Delores M. Etter Top Scientists and Engineers of the Year Award, in part for his SERDP funded work on renewable composites. He earned both his bachelor’s degree in Chemistry and his doctoral degree (2005) in Organometallic Chemistry from The University of Utah.
Dr. John La Scala is the Chief of Coatings, Corrosion and Engineered Polymers Branch at the Army Research Laboratory (ARL) at Aberdeen Proving Ground, MD. Dr. La Scala has been working on bio-based, environmentally friendly resins and polymers technology for composites, adhesives and coatings applications for 17 years. His scientific advances are evidenced by over 50 open literature publications, while his ability to innovate are demonstrated by his numerous patents and his ability to transition new technology to the field and commercial industry.
Dr. La Scala received a B.S. in chemical engineering from the University of Virginia in 1997, and a Ph.D. in chemical engineering from the University of Delaware in 2002. He is the recipient of multiple national awards including the 2013 Presidential Award in Green Chemistry from the EPA and ACS (noted contributor), the 2011 Secretary of Defense Environmental Excellence in Weapon System Acquisition Small Program Award, the 2010 ESTCP Weapons Platform Project of the Year Award (Demonstration of Composites with Low Hazardous Air Pollutant Contents for Military Applications) and the 2005 SERDP Weapons Platforms Project of the Year Award (Environmentally Friendly High Performance Composites for Army Applications).