The dynamic behavior of poly (methyl methacrylate) based nano-rubbers subjected to impact and perforation: Experimental investigations

A new family of Nanostructured PMMA offering superior impact resistance while keeping transparency whatever the temperature, has been developed by ARKEMA. The Nanostructured PMMA products are commercialized by Arkema under the brand names Altuglas (R) ShieldUp (cast sheet) and Arkema Nanostrength (resins). Arkema Nanostructured PMMA products have been developed with the main objective of replacing glass and Polycarbonate in various applications such as automotive window and safety glazing. In this study, only Altuglas ShieldUp has been studied and compared to standard PMMA, impact PMMA and Polycarbonate. Quasi static and dynamic characterization experiments were conducted on the different materials under compression loading. A wide range of temperatures and strain rates were covered during experimental testing. Furthermore, several nano indentation tests were performed on both annealed and non -annealed Altuglas Shieldup specimen. In order to characterize and compare the perforation resistance, ballistic impact experiments conducted on the four amorphous polymers were carried out using pneumatic gas gun having different impact velocities varying from 8 to 161 m/s. The resistance force during impact and perforation was measured at different initial impact velocities and different thicknesses. All the projectiles are conical-nose shaped and 12.8 mm in diameter and 28 g in weight. The ballistic impact device is equipped with two laser sensors for velocities measurements and four piezoelectric sensors for dynamic force measurement. The velocity measurements allow to draw the ballistic curves as well as the energy balance. The failure patterns of the impacted targets are observed using the X-ray tomography. It was observed from quasi-static and dynamic mechanical properties, that the nanostructured PMMA (Shieldup) exhibits a slight lower Young's modulus and yield stress when comparing with pristine PMMA, however both materials have the same glass transition temperature. Perforation tests reveal that the Shieldup presents a significant impact resistance as compared with the neat resin and the impact PMMA (PMMA containing rubber modifiers at micrometer scale). When increasing the plate thickness, the rate of the increase of ballistic limit of Shieldup becomes more important than the one of Polycarbonate (PC).