After obtaining Ph.D. from North Carolina State University in 1984 Dr. Netravali joined the Department of Materials Science and Engineering at Cornell University as a postdoctoral associate. In 1985 he joined the Department of Mechanical Engineering as a research associate. In August of 1987 he joined the Department of Fiber Science & Apparel Design as an assistant professor of Fiber Science. His main research is in the field of Fiber Reinforced Composites and Green Materials. Within the area of composites his group has developed Green resins from plant-based proteins and starches and reinforced them using plant-based fibers to fabricate environment-friendly, Green Composites for a variety of applications. In the past few years, his research group has developed green resins that have excellent mechanical properties; in some cases, better than commonly used epoxy resins. These carbon-neutral alternatives for the conventional petroleum-based composites are fully compostable at the end of their life. His group has also made Advanced Green Composites with high strength and toughness that may be used in structural and ballistic applications. The second focus is in modification of fiber surfaces to control fiber/resin interface characteristics in composites. His research group has used many techniques to modify fiber surfaces to control their topography and chemistry and thus their adhesion to resins and mechanical properties of composites. His group has used polymerizing and non-polymerizing plasmas, pulsed excimer laser, high power ion beam, solvent treatments, etc., to modify fiber surfaces. A third focus of his group is to develop new green nanofibers from proteins for a variety of applications including high efficiency filtration and bacterial cellulose from food and agricultural waste for composites and medical applications.
Fiber reinforced composites are used in many applications where metals have been commonly used because of their high specific mechanical properties. Most high strength fibers and resins used in these ‘Advanced Composites’ are based on petroleum feedstock, a non-renewable resource that is expected to be almost non-existent 50-60 years from now. With double digit growth in production and use of composites in the past couple of decades, their disposal problem has become difficult and expensive. Because composites are made combining two dissimilar materials they cannot be recycled or reused easily. While only a small fraction of the composite waste is incinerated to obtain energy or crushed into powder for use as low grade filler, most of the composites, after their intended life, end up in landfills. Major part of our research is directed towards creating fully sustainable and environment-friendly ‘green’ resins and composites using yearly renewable plant-based fibers and polymers that are mostly carbon neutral. At the end of their life green composites can be easily composted creating organic soil for growing more plants. Current versions of green composites based on modified plant proteins and starches developed in my research group are not only suitable for use in packaging, housing or transportation panels, furniture, board sports and secondary structural applications, but the high strength Advanced Green Composites made using liquid crystalline cellulose fibers and soy protein based resins have toughness comparable to aramid fiber based composites. These advanced green composites may be used as primary structural elements or for ballistic applications.
Second part of our research in composites involves Advanced Composites made using high strength fibers such as graphite, aramids and ultra-high molecular weight polyethylene (UHMWPE) that are used in a wide range of applications from aerospace to sports gear and from automobile body parts to civil structures. Critical mechanical properties of composites such as toughness and longitudinal and transverse strength are controlled by fiber/resin interfacial bonding. My research group is involved in modifying fiber surface topography and chemistry to control their interfacial (adhesion) with different resins. We have used many techniques including plasmas, pulsed excimer laser, high power ion beam, solvent treatments and their combinations to obtain desired chemical groups on the fiber surface and modify surface roughness to control the fiber/resin interfacial bonding. We are also working to control resin and fiber/resin interfacial properties using nanoparticles and nanofibrils in resin or fiber surfaces.
Our research in nanofibers involves creating new nanofibers such as bacterial cellulose (BC) using food and agricultural waste and green nanofibers from plant and other proteins and starches for high efficiency filters that can catch dust, bacteria as well as air borne viruses. The BC nanofibers can be used for applications including composites and medical.
Current research projects:
- Development of fully biodegradable, environment-friendly ‘green’ composites and nanocomposites using plant based fibers and resins
- Surface modification of high strength fibers to control their adhesion to various resins including nanophase epoxies
- Development of bacterial cellulose and high strength composites
- Development of 'green' nanofibers for high efficiency filters
Dr. Netravali is a member of the American Chemical Society, the Fiber Society and the American Nano Society. He is an Adjunct Professor at the Universidade Federal do Amazonas (UFAM) in Manaus, Brazil, and a Visiting Professor at Kyoritsu Women’s University in Tokyo, Japan, and has been an International Research Fellow at the Composites Center at Doshisha University, Kyoto, Japan. He serves on Editorial Advisory Boards of 5 research journals; Composites Science and Technology, Journal of Adhesion Science and Technology (JAST), Journal of Biobased Materials and Bioenergy (JBMBE), Journal of Engineered Fibers and Fabrics (JEFF) and Textile Research Journal (TRJ). He is a member of the Advisory Committee of the International Workshop on Green Composites, a member of the International Scientific Committee for the Amazonic Green Materials and Processes Meetings and a member of the Scientific Committee and Review Board of the International Conferences on Composites/Nano Engineering (ICCE). He is also an Advisory board member for the Sustainable Textile Center, Buenos Aires, Argentina. He is a Faculty Fellow at the David R. Atkinson Center for a Sustainable Future at Cornell University.
- I am a member of the Cornell Center for Materials Research (CCMR) and have worked through the center on some of their outreach activities.
- I am also a Faculty Fellow at the Atkinson Center for Sustainable Future (ACSF) and participate in the center activities.
- I am also a member of the Cornell Center for Global Sustainable Enterprise (CGSE) and have participated in their activities including presenting lecture on Green Materials Opportunities.
- I have delivered several lectures to county agents and other groups invited by CCE on my research in 'Green Materials' and its usefulness.