All are welcome to an invited seminar by Dr. Agnes Ostafin, Chemical Engineering, Research Associate Professor, Director Center for NanoMaterials, NanoInstitute University of Utah. The title is: “Engineered Materials for Personal Protection.” The seminar will be from 3:00 to 4:00 p.m. on Wednesday November 12, in WEB L102. There will be light refreshments afterwards.

There has been a parallel but separate development of high strength polymers like Kevlar and materials made from high strength nanomaterials like CNTs. Over the last ten years the situation has slowly been changing. The typical problems relating to integration of CNTs with other materials are being overcome. In addition smart polymers have emerged and the price of CNTs is steadily falling. Today, the possibility of a product combining features of Kevlar and CNTs is very real. The technology developed by the UU NanoInstitute in partnership with local industry involves practical applications nanoparticle composites. What distinguishes it from the competition in ballistics protective gear is a different philosophy in material design. Instead of focusing on one specific type of CNT formulation we have used blends of CNTs and other materials to improve ballistic performance without compromising flexibility and elasticity needed for clothing. We can tune the mechanical properties of our materials as needed for specific applications.

Stopping a bullet requires a material (or layer of material) perform at least three separate functions: 1) bullet distortion, 2) bullet slow down and 3) bullet stoppage. The characteristics of a material required to perform each function is different, and for this reason most manufacturers of bullet resistant products use more than one kind of fabric. To effectively stop a bullet in a short distance the bullet has to be quickly distorted to increase its impact footprint as much as possible so the maximum number of fibers can be employed to dissipate its energy. Distortion requires a harder, non-yielding fabric while slow-down requires the fabric be softer to able to absorb as much energy as possible but without yield in the direction of bullet movement. A fabric that can melt, expend energy by cracking, or shift its fibers to further increase contact with the bullet is needed. Since bullets may break up and release fragments the secondary layers have to be able to do its job at different lengths scales. For both of the first two steps, the weave of the fabric and the way the threads work together is crucial. Most assemblers of personal protective gear rely on manufacturer’s recommendations and have limited ability to tailor the package of fabric layers for specific needs, shapes, and conditions. If the first two steps are accomplished then the last step, bullet stoppage, is straightforward. This part of the fabric package has to be unyielding (to reduce bruising), and be able to dissipate most of the energy in directions perpendicular to the bullet’s travel.
Because of the variety of bullet calibers, shapes, and materials, the amounts of material devoted to each of the three stages has to vary, along with the degree to which it performs its function. It’s often surprising to hear that a product that always resists penetration of a high caliber bullet can sometimes allow occasional penetration of lower caliber bullets due to their shape and physical size. Thus really, there is no one size fits all fabric bundle that can do everything. Our technology aims at providing more choices by using engineered nanoparticle composites to extend the range of bullets that can be reliably stopped by a given fabric with minimal increase in weight or cost. It is possible then for a manufacturer to selectively tweak the performance of a material for different uses, whether it is for chest, leg, or head protection. It can even be used to tailor the protection in different parts of the product, for instance neck or underarms, seams, ribs or groin, etc.

Dr. Agnes Ostafin is a Research Associate Professor in the Department of Chemical Engineering and the Director of the Center for NanoMaterials, NanoInstitute University of Utah. Dr. Agnes Ostafin is a published scientist, national and international speaker, author/editor of over 70 scientific manuscripts and book chapters with a PhD in chemical physics from the University of Minnesota; a Certificate in Engineering Management from Drexel University; and chemistry, biological sciences, and biophysics degree degrees from Wayne State University. She has 15 years of experience in managing short and long-term projects in multiple technology areas including nanoparticles, nanostructured materials, nanofabrication, emulsions, microparticles, encapsulations, coatings, thin films, composites, hydrocarbon liquids/glasses, polymers, carbon nanotubes, ceramics, biological and biomedical materials. In addition she has been involved in pilot scale process development and production; evaluation of product/process quality and stability; new technology evaluation and adaptation to project goals, laboratory set up, equipment and process validation, process management and operations; and a wide range of analytical and chemical synthesis methods including spectroscopy, microscopy, imaging, electrical, photochemical, and biological process design.