Adhesive Properties of Acrylic Interlayer with Cellulose Nanofibers in Glass/polycarbonate Laminated Safety Glass

<p>Safety glasses used in machine tools require good impact and solvent resistance, and high transparency. These requirements can be satisfied by glass/polycarbonate (G/PC) laminated safety glass incorporating acrylic interlayer (ACIL). We focused on cellulose nanofibers having a diameter of a few dozen nanometers and a high aspect ratio as a filler in ACIL to enhance the impact resistance of G/PC laminated safety glass. In previous research, the G/PC laminated safety glass incorporating ACIL with CNFs (CNF/ACIL) showed an enhanced impact resistance. However, the effect of the adhesive properties of CNF/ACIL on the impact resistance of G/PC laminated safety glass incorporating CNF/ACIL is unclear. The objective of this study was to investigate the adhesive strength at G-CNF/ACIL and PC-CNF/ACIL adhesive interfaces. Cleavage tests and tensile shear tests were performed on specimens with G-CNF/ACIL and PC-CNF/ACIL adhesive interfaces, and the effects of loading mode and CNF concentration in ACIL on the adhesive strength of the specimens were discussed. In addition, finite element analysis (FEA) of the drop weight tests of the G/PC laminated safety glass considering adhesive strength at interfaces was carried out using LS-DYNA. As a result of experiments, the adhesive strength of the specimens with G-CNF/ACIL and PC-CNF/ACIL adhesive interfaces decreased when CNF concentration in ACIL increased. Also, damage states in fracture surfaces of the specimens with G-CNF/ACIL adhesive interface were changed by increasing CNF concentration in ACIL. However, the fracture surface of the specimens with PC-CNF/ACIL adhesive interface showed the same damage state at different CNF concentrations in ACIL. As a result of finite element analysis, attenuation of the predicted velocity of impactor after collision became stronger when shear failure stress of PC-ACIL adhesive interface in the G/PC laminated safety glass increased. </p>