Multi-axial aramid fabrics have a wide range of applications in the construction of composite structures for body armor. Nanoparticles, which include nanosilica, are one of the most common nanofillers for these structures. The particles of nanosilica possess nanometer dimensions with high specific surface area. Silane coupling agents are mostly used for modifying nanosilica surface in order to prevent silica agglomeration. Incorporation of nanosilica treated with silane adhesion promoter, in the matrix part of the hybrid composite form, leads to increased resistance to the bullet shock impact. In this study, the resistance to penetration of a shot bullet was tested for four samples of the aramid fabric composite forms. All fabrics were coated with γ-aminopropyl triethoxysilane (AMEO silane)/ethanol solution. Two samples were impregnated with poly (vinyl butyral) (PVB)/ethanol solution, while the other two were impregnated with the same solution, but with the addition of the 30 wt.% AMEO silane modified silica nanoparticles as reinforcement. The samples were both hard and flexible options. The bullet-shooting test was applied to all the composites by two different bullet types. The structural design of the samples improved the ballistic resistance after the bullets were shot. Some ballistic image analyses for print and penetration depth of the samples were performed using Image Pro-Plus software.

The goal of this study was to investigate the effect of the structure of Mn-Al layered double hydroxide (LDH) on the adhesion behavior of composite adhesives on two Al alloys (L3005 and L8079). The composite adhesives were made out of the UV-curing Bisphenol A glycidylmethacrylate/triethylene glycol dimethacrylate (BT) as polymer matrix and the addition of 1, 3, and 5 wt. % of Mn-Al LDH as adhesion enhancers. Adhesion was evaluated by using the micro Vickers hardness testing procedure. The wetting angle of composite adhesives to the Al substrates was measured and compared to the adhesion parameter b obtained from the microhardness tests. The highest increase in adhesion was observed for BT with 5 wt. % of Mn-Al LDH on L3005 substrate, which was more than 15 times higher than the adhesion for the neat BT. The morphological segregation of composite adhesives after the contact with Al substrates was examined by optical microscopy and a higher compatibility of Mn-Al LDH particles with L3005 substrate was found. The methods used for the adhesion properties assessment suggested that the Mn-Al LDH was the best adhesion enhancer of the BT matrix for L3005 substrate containing a higher content of Mn and surface hydroxyl groups.

In this study poly (vinyl butyral)/silica (PVB/SiO₂) composite films were subjected to the cavitation process. The experiments were carried out with a 10 wt.% PVB solution in ethanol. Silica nanoparticles were added into the solution in different concentration of 1, 3 and 5 wt.% SiO₂ in regard to PVB. Composite films were cast from these solutions and subjected to ultrasonic cavitation. Optical images of their surfaces were analyzed before and after cavitation, by Image-Pro Plus software. The results revealed that the PVB film with 5 wt.% SiO₂ nanoparticles demonstrated the greatest improvement in microhardness with the best cavitation resistance compared to other films.