Thickness Of Polyethylene Layer Research Articles

Characteristics of Protons Exiting from a Polyethylene Converter Irradiated by Neutrons with Energies between 1 keV and 10 MeV

Monte Carlo method has been used to determine the efficiency for proton production and to study the energy and angular distributions of the generated protons. The ENDF library of cross sections is used to simulate the interactions between the neutrons and the atoms in a polyethylene (PE) layer, while the ranges of protons with different energies in PE are determined using the Stopping and Range of Ions in Matter (SRIM) computer code. The efficiency of proton production increases with the PE layer thickness. However the proton escaping from a certain polyethylene volume is highly dependent on the neutron energy and target thickness, except for a very thin PE layer. The energy and angular distributions of protons are also estimated in the present paper, showing that, for the range of energy and thickness considered, the proton flux escaping is dependent on the PE layer thickness, with the presence of an optimal thickness for a fixed primary neutron energy.

Scaling Effects on Color and Transparency of Multilayer Polyethylene Films in Polarized Light

AbstractTransparency and color of polyethylene film layered packages change with the number of layers. When polyethylene layer thickness is between 50 μm and 200 μm, each additional subsequent layer in the package leads to an abrupt change in color and transparency. Polarized light optical effects can be used to manufacture packaging films and labels with forgery protection. A significant influence of the scaling factor on the latent effect and optical properties of the film package is demonstrated for one to six layers with the total thickness of 200 ± 50 μm. Prior thermal treatment of individual layers before they are assembled into a package or assembled package heat treatment change the laminate color. This allows hidden marking and recording text or graphics on the multi‐layer films, not visible under normal lighting conditions, but appearing when viewed in polarized light, or through the polarizer. The paper demonstrates obtaining bright colored decorative or packaging materials, along with light filters for advertising and information displays, which change color with the viewing angle. New materials can be prepared using standard industrial equipment and widely used polymers. By changing the location of the film polarizers, the number of layers and the film thickness, laminates vary in brightness and color from blue to red.

Nondestructive Characterizations of Polyethylene/Nylon Laminates by Near-Infrared Spectroscopy

The use of near-infrared (NIR) spectroscopy for the rapid and nondestructive analysis of food packaging laminates containing polyethylene (PE), polyamide-6 (PA-6), and ethylene vinyl alcohol (EVOH) layers is demonstrated. The method of Pathlength Correction with Chemical Modeling (PLC-MC) is used to estimate the total laminate thickness, and Principal Component Regression (PCR), is used to estimate the thickness percentages of PE and EVOH in the laminates, from NIR reflective-transmission spectra in the region 1500–2500 nm. Results indicate that the NIR method can be used to determine the total laminate thickness within 2–4 μm, the PE layer thickness percentage within 0.7–1.8%, and the EVOH layer thickness within 0.7–0.8 μm. In addition, detailed observation of the PCR models indicates that the NIR method is also sensitive to the absorbed water content, the morphology of the polymers, and perhaps the amount of polyurethane adhesive in the laminates. The usefulness of PCR outlier detection, for identification and characterization of strange samples, and principal component rotation, for improvement of PCR model interpretability, is also demonstrated.