Most advanced composites currently available are made using non-degradable polymeric resins such as epoxies, esters, polyurethane, etc., and high strength and/or high stiffness fibers such as graphite, aramids, and glass, designed for long term durability. While they have desirable mechanical, thermal and chemical properties, they have two major disadvantages. First, the materials used are not sustainable; the high performance fibers (except glass) and resins are almost entirely derived from petroleum, and secondly these composites are non-degradable under normal environmental conditions. In recent years, the growing environmental concerns have pushed research in the area of bio-degradable green composites since they do not require petroleum (source of greenhouse gas emissions) and land-fills at the end of their lives. In green polymer composites, one of the two chemicals from which they are synthesized can be produced sustainably reducing their carbon footprint. For example, polyurethanes (PU) can now be produced using polyols from soybean oil, polyethylene terephthalate (PET) from ethylene glycol, and polybutylene succinate (PBS) from succinic acid. Use of renewable plant-based lignocellulosic fibers has been a natural choice for reinforcing (or filling) polymers to make them greener. Plenty of examples can be found where plant-based fibers are used for reinforcing non-degradable thermoplastic polymers such as PP, high, medium, and low density polyethylene (HDPE, MDPE, LDPE), nylons, polyvinylchloride (PVC), and polyesters as well as thermoset resins such as epoxies and esters to produce greener composites. Due to their good mechanical properties, longer plant-based fibers, extracted from the stems or leaves of plants such as abaca, bamboo, flax, henequen, hemp, jute, kenaf, pineapple, ramie, sisal, etc., are being evaluated as low cost alternative reinforcements to commonly used glass fibers to make composites. These fibers are annually renewable, as compared to wood which takes 20–25 years to grow before it can be cut and used. Significant research efforts are currently being spent in developing a new class of fully biodegradable or compostable green nanocomposites by combining natural fibers with biodegradable resins. Most of the current technology is still in the research and development stage. This presentation will review some of these developments and their current and potential applications, especially in transportation sector.
Prior to joining the faculty at Washington University in 2001, Professor Agarwal was the Chair of the Aerospace Engineering Department at Wichita State University from 1994 to 1996 and the Executive Director of National Institute for Aviation Research from 1996 to 2001. From 1994 to 2001, he was also the Bloomfield Distinguished Professor at Wichita State University.
From 1978 to 1994, Professor Agarwal worked in various scientific and managerial positions at McDonnell Douglas Research Laboratories in St. Louis. He became the Program Director and McDonnell Douglas Fellow in 1990. From 1976 to 1978, Professor Agarwal worked as a NRC Research Associate at NASA Ames Research Center and as a Principal Research Engineer at Rao and Associates in Palo Alto, California from 1975 to 1976.
Over a period of 45 years, Professor Agarwal has worked in Computational Fluid Dynamics (CFD), Computational Magnetohydrodynamics (MHD) and Electromagnetics, Computational Aeroacoustics, Multidisciplinary Design and Optimization, Rarefied Gas Dynamics and Hypersonic Flows, Bio-Fluid Dynamics, and Flow and Flight Control. More recently, he has devoted some of his efforts in nanotechnology and renewable energy systems - in particular wind, solar and biomass. He is the author and coauthor of over 600 publications and serves on the editorial board of more than 20 journals. He has given many plenary, keynote and invited lectures at various national and international conferences in over 60 countries worldwide. Professor Agarwal continues to serve on many professional, government, and industrial advisory committees.
Professor Agarwal is a Fellow of 23 societies including: American Association for Advancement of Science (AAAS), American Institute of Aeronautics and Astronautics (AIAA), American Physical Society (APS), American Society of Mechanical Engineers (ASME), Institute of Electrical and Electronics Engineers (IEEE), Society of Automotive Engineers (SAE), Society of Manufacturing Engineers (SME), American Academy of Mechanics (AAM), American Society of Civil Engineers (ASCE), Chinese Society of Aeronautics and Astronautics (CSAA), Institute of Pysics (IOP), UK, Institute of Engineering and Technology (IET), Energy Institute (EI), Australian Institute of High Energetic Materials, American Society for Engineering Education (ASEE), Academy of Science of St. Louis, Royal Aeronautical Society (RAeS), etc. and World Innovation Foundation (WIF). He has received many honors and awards for his research contributions including the ASME Fluids Engineering Award (2001), ASME Charles Russ Richards Memorial Award (2006), Royal Aeronautical Society Gold Award (2007), AIAA Aerodynamics Award (2008), AIAA/SAE 2009 William Littlewood Lecture Award (2009), James B. Eads Award of Academy of Science of St. Louis (2009), ASEE/AIAA John Leland Atwood Award (2009), SAE Clarence Kelly Johnson Award (2009), SAE Franklin W. Kolk Award (2009), AIAA Lindbergh Award (2010), SAE Aerospace Engineering Leadership Award (2013), SAE Excellence in Engineering Education Award, SAE International Medal of Honor (2015) and AIAA Reed Aeronautics Award (2015) among many others.