|dc.description.abstract||Improving the ballistic impact resistance of hybrid polymer matrix composites through addition of micro- and nano-particles as fillers is the principal goal of this research. Development of light-weight ballistic plates, made of polymer matrix composites with improved ballistic resistance, can offer a solution of shielding with lighter, thinner, stronger and less expensive materials than the conventional ballistic plates. The use of micro- and nano-particles in low concentrations can achieve this goal without compromising the density or strength of the new armor plates.
Firstly, laminated hybrid composites consisting of aluminum alloy plates, epoxy resin and Kevlar® fabrics were developed. Shear thickening fluid (STF) made of nano-particles of colloidal silica (SiO2) was impregnated into Kevlar® fabrics to determine its effect on the energy absorption behavior of the composites. STF decreased the tendency of Kevlar® fibers to rupture during projectile penetration, and thus, increased its impact energy absorption performance when compared to the samples made of Kevlar® neat fabrics (containing no STF). Similar laminated hybrid composites were subsequently built through impregnation of micro- and nano-particles of aluminum, gamma alumina, silicon carbide, colloidal silica and potato flour into Kevlar fabrics by mixing these particles with polyethylene glycol. The obtained laminates were evaluated to determine their impact resistance and energy absorption capabilities under ballistic impact. The plates containing aluminum and colloidal silica nano-powders have the highest energy absorption capability of between 679 up to 693 J for plate thickness and areal density of about 10.8 mm and 1.9 g/cm2, respectively. These laminates can meet the protective requirements for levels IIA, II, and IIIA to resist ballistic impact from pistols caliber 9 mm.
In another approach, hybrid composite armor plates based on high density polyethylene (HDPE) were prepared by using 10 wt.% of Kevlar® short fibers, and 20 wt.% chonta palm wood, potato flour, colloidal silica or gamma alumina particles. Addition of colloidal silica and gamma alumina nano-particles improve stiffness by 43.5% and increase impact energy absorption capability by 20%, compared to control sample, which is HDPE containing 10 wt.% Kevlar® short fibers.
Hybrid bio-composites made of 10 wt.% Kevlar® short fibers and varying amount of chonta wood particles (10, 20, 30 wt. %), as additional reinforcement, were also developed and investigated. The hybrid composite plates containing 10 wt.% chonta palm wood micro-particles exhibited the highest energy absorption capability of 62.4 J, which is equivalent to 19.5 % improvement over control specimens: HDPE reinforced with 10 wt.% Kevlar® short fibers.
Finally, bio-composites made of HDPE reinforced with varying fractions of micro-particles of chonta palm wood (10, 20, 25, and 30 wt. %) were developed and characterized. The ballistic impact performance of the biocomposites containing 25 wt.% chonta palm wood particles exhibited the highest energy absorption of 53.4 J, which represents a 41.3% improvement over the unreinforced HDPE specimens with similar thickness and density.||