Journal of Plastic Film & Sheeting

Zinc oxide–Barium titanate–Polycarbonate (ZnO−BaTiO₃−PC) nanocomposites were prepared to investigate effect of ZnO–BaTiO₃ mixed nanoparticles on the optical, electrical, and thermal properties of polycarbonate (PC). The UV-visible absorption spectra was measured for the nanocomposites at room temperature between 200 and 800 nm and the optical energy gap was determined from the measured absorption coefficient data. Optical results reveal that BaTiO₃ ceramic has a strong absorption below 300 nm while ZnO has a strong absorption peak at 367 nm and the UV absorption in these regions depends on the ZnO and BaTiO₃ concentration. This indicates that the PC UV shielding region can be controlled through the mixed BaTiO₃-ZnO nanoparticle weigh ratios. Also, 10 wt% BaTiO₃ nanoparticles in PC insignificantly affects the optical energy gap whereas 10 wt% ZnO nanoparticles in PC decreases the optical gap from 4.14 to 3.9 eV. Results obtained from DC conductivity and thermal analysis reveal that adding BaTiO₃ nanoparticles into PC will decrease DC conductivity, restrict chain mobility, and increase thermal stability while, adding ZnO nanoparticles to PC increases DC conductivity, enhances chain mobility, and decreases the thermal stability. The optical, electrical, and thermal properties of these nanocomposites can be controlled by adjusting the ZnO to BaTiO₃ nanoparticles weight ratios in the PC matrix.

In thermoforming, flat plastic sheets are transformed into complex shapes by first softening by radiant heat transfer, and then by shaping. During the softening step, the sheet first bows while still solid, then sags while soft. In this article, we derive the heat flux distributions over both faces of a bowing or sagging sheet, along with the corresponding temperature profiles through and across the bowing or sagging sheet. These predictions can help plastics engineers to present a sheet of uniform temperature to a thermoforming mold. A worked example is included to show how to use the results.

Tensile and dynamic mechanical properties of thin film epoxy composites containing different types of fillers such as synthetic diamond (SD), silicon nitride, and boron nitride (BN) were investigated. The filler contents were varied between 0 and 2 vol.%. Spin coating technique was employed to produce thin film with thickness of 40–60 µm. Tensile test results show that addition of SD obviously improves the strength and Young's modulus, and increases the storage modulus (E′) of the epoxy thin film composite. The addition of 2 vol.% SD increases the Young's modulus and tensile strength by almost two times the properties of neat epoxy. Scanning electron microscopy showed void formation and poor interfacial analysis which explains the reduced tensile strength of BN filler epoxy composites.