High-density Polyethylene System Research Articles

Morphological and Gamma-Ray Attenuation Properties of High-Density Polyethylene Containing Bismuth Oxide.

For extensive radiation exposure, inventing a novel radiation shielding material is a burning issue at present for the purpose of life saving. Considering this thought, in this study, by adding sundry amounts of Bi2O3 into pure high-density polyethylene (HDPE), six HDPE systems were prepared to evaluate the radiation shielding efficiency. These HDPE systems were HDPEBi-0 (pure HDPE), HDPEBi-10 (10 wt% Bi2O3), HDPEBi-20 (20 wt% Bi2O3−), HDPEBi-30 (30 wt% Bi2O3), HDPEBi-40 (40 wt% Bi2O3), and HDPEBi-50 (50 wt% Bi2O3). The values of the linear attenuation coefficients of the experimental results (calculated in the lab using HPGe) were compared with the theoretical results (obtained using Phy-X software) at 0.060, 0.662, 1.173, and 1.333 MeV energies. To ensure the accurateness of the experimental results, this comparison was made. It was crystal clear that for energy values from 0.06 MeV to 1.333 MeV, all the experimental values were in line with Phy-X software data, which demonstrated the research setup’s reliability. Here, the linear attenuation coefficient (LAC), and mean free path (MFP) shielding parameters were assessed. At the energy of 1.333 MeV, sample HDPEBi-0 showed an HVL value 1.7 times greater than that of HDPEBi-50, yet it was 23 times greater at 0.0595 MeV. That means that for proper radiation protection, very-low-energy HDPE systems containing 10–50% Bi2O3 could be used; however, the thickness of the HDPE system must be increased according to the energy of incident radiation.

Effect of Hindered Amine Light Stabilizer on Properties of HDPE/Kaolin Composites for Hydraulic Gate and its Mechanism Analysis

High density polyethylene (HDPE)/kaolin composites with different hindered Amine light stabilizers were prepared by blending granulation. The mechanical properties and dynamic thermodynamic changes before and after aging were discussed and studied. The precipitates were analyzed by FI-IR and H1-NMR, and the precipitation reason and anti-aging difference of different light stabilizers were discussed and compared. The results showed that the mechanical properties retention rates of light stabilizer 2020, light stabilizer 944, light stabilizer 123, light stabi-lizer 770 and light stabilizer 292 were 87.1%, 81.7% and 79.1%, respectively %Light stabilizer 2020 and light stabilizer 944 with large molecular weight are more easily compatible with the system, not easy to precipitate, and have a better an-ti-aging effect. At the same time, light stabilizer 2020 with dense hindered amine structure has excellent anti-aging effect. This study provides a reference for the selection of light stabilizer and failure analysis of light aging resistance of HDPE system.

Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background.

We present a compact two-lens high-density polyethylene (HDPE) $ f/1.6 $f/1.6 refractor design that is capable of supporting a 28-deg diffraction-limited field of view at 1-mm wavelengths and contrast it to a similar two-lens refractor using silicon lenses. We compare the optical properties of these two systems as predicted by both geometrical and physical optics. The presented analysis suggests that by relaxing telecentricity requirements, a plastic two-lens refractor system can be made to have a surprisingly large field of view. Furthermore, this HDPE system is found to perform comparably to a similar silicon system across a wide field of view and wavelengths up to 1 mm. We show that for both telescope designs, cold stop spillover changes significantly across the field of view in a way that is somewhat inconsistent with Gaussian beam formalism and simple $ f $f-number scaling. We present results that highlight beam ellipticity dependence on both pixel location and pixel aperture size-an effect that is challenging to reproduce in standard geometrical optics. We show that a silicon refractor design suffers from larger cross-polarization compared to the HDPE design. Our results address the limitations of relying solely on geometrical optics to assess relative performance of two optical systems. We discuss implications for future refractor designs.

A biomaterial for scaffold applications: Thermal properties analysis of a PSZ-TiO2/HDPE system

High-density polyethylene (HDPE) matrices reinforced with titanium dioxide (TiO2) biocomposites are seen as promising biomaterials due to their superior properties. In this work, an attempt was made to study the effects of six biocomposites hybrid Titanium dioxide (TiO2) and yttria-stabilized zirconia (Y-PSZ) samples reinforced with high-density polyethylene (HDPE) matrices, split into two groups, in terms of withstanding the daily activity loads imposed by human bone grafting and repairs. The fabricated composites were investigated using the hot-pressing technique at different compression pressures and compounding temperature. To achieve characterization, thermal analysis of the process using differential scanning calorimetry (DSC) techniques was undertaken. To improve and verify the results, Design Expert 11.0 software and a response surface methodology (RSM) technique were used. For both nanofabricated types, the results showed that an increase in TiO2 ceramic filler from 1% to 10 %, caused percentage crystallization to increase by 14.58%. The heat of system fusion for the second fabricated system also decreased by 11%. These results show that this addition reduced the heat of system fusion by 109% compared with previous studies. The glass transition (onset) and end (melting) temperature also increased with increases in the applied compression pressure and hot-pressing temperature when a small value, 1%, of TiO2 ceramic nanoparticle fillers in the HDPE matrix. The temperature values were increased when using higher compression pressure of between 60 and 90 MPa, and the onset temperature reached a maximum value of 127 °C. This increase in onset temperature continued when using higher values of TiO2 Nanoceramic filler and the onset temperature reached its maximum value with 10% TiO2 and 2% PSZ Nanoceramic fillers added to the fabricated nanomaterial system. The differential scanning calorimetry (DSC) scanned curves and the 3D atomic force microscopy (AFM) microstructure and granularity distribution images for both fabricated nanocomposite systems clearly showed that the interconnections between the filler’s ceramic nanoparticles within the polymeric matrix offer high surface roughness values due to the excellent nanofiller particle distribution within the polymeric matrix.

Estimation of neutron energy distributions from prompt gamma emissions

A technique of estimating the incident neutron energy distribution from emitted prompt gamma intensities from a system exposed to neutrons is presented. The emitted prompt gamma intensities or the measured photo peaks in a gamma detector are related to the incident neutron energy distribution through a convolution of the response of the system generating the prompt gammas to mono-energetic neutrons. Presently, the system studied is a cylinder of high density polyethylene (HDPE) placed inside another cylinder of borated HDPE (BHDPE) having an outer Pb-cover and exposed to neutrons. The emitted five prompt gamma peaks from hydrogen, boron, carbon and lead can be utilized to unfold the incident neutron energy distribution as an under-determined deconvolution problem. Such an under-determined set of equations are solved using the genetic algorithm based Monte Carlo de-convolution code GAMCD. Feasibility of the proposed technique is demonstrated theoretically using the Monte Carlo calculated response matrix and intensities of emitted prompt gammas from the Pb-covered BHDPE–HDPE system in the case of several incident neutron spectra spanning different energy ranges.

Interfacial interaction of clay with binary blends of polyamide 6 with High-Density Polyethylene (HDPE) and HDPE-graft-acrylic acid studied by Positron Annihilation Lifetime Spectroscopy

Positron Annihilation Lifetime Spectroscopy (PALS) has been utilised to investigate the free-volume properties of polyamide 6 (PA-6)/HDPE, PA-6/HDPE-graft-acrylic acid (PEAA) and their nanocomposites with organo-clay (Oclay). There is a great difference in the average size of free-volume holes (R) and the fractional free-volume (fv) of PA-6 and HDPE owing to their different polarity. And the variations of R and fv as functions of Oclay content are different between two blends. In PA-6/HDPE system, when added 1.2 per hundred resin (phr) and 2.4 phr Oclay, R and fv increased slightly, while in PA-6/PEAA system, R and fv decreased. The complicated relationship between the free-volume and the Oclay content is due to the interaction effect of Oclay on blends' interface.

Bamboo–Fiber Filled High Density Polyethylene Composites: Effect of Coupling Treatment and Nanoclay

High density polyethylene (HDPE)/bamboo composites with different nanoclay and maleated polyethylene (MAPE) contents were fabricated by melt compounding. The compounding characteristics, clay dispersion, HDPE crystallization, and mechanical properties of the composites were studied. The equilibrium torque during compounding decreased with use of clay masterbatch and increased with the addition of MAPE. The X-ray diffraction (XRD) data showed that the clay was exfoliated only when 1% clay was added to pure HDPE without MAPE. For HDPE/bamboo systems, MAPE was necessary to achieve clay exfoliation. For pure HDPE system, both dynamic and static bending moduli increased, while impact strength decreased with increased clay loading. For the HDPE/bamboo fiber composites, tensile strength, bending modulus and strength were improved with the use of MAPE. The use of the clay in the system led to reduced mechanical properties. Techniques such as pre-coating fibers with clay–MAPE mixture are needed to enhance the synergetic effect of the clay and bamboo fiber on the composite properties in the future study.

High-Density Polyethylene Membrane Containing Fe0 as a Contaminant Barrier

To improve the performance of polymer-based containment barriers with respect to the breakthrough of chlorinated solvents, a high-density polyethylene (HDPE) membrane containing zero-valent iron ( Fe0 ) nanoparticles was developed as a reactive barrier. The performance of the reactive membrane was evaluated by challenging it with carbon tetrachloride in a diaphragm cell apparatus. In a Fe0 /HDPE system, reaction between carbon tetrachloride and Fe0 did not occur due to a lack of water in the polymer matrix. A glycerol-modified Fe0 /HDPE membrane successfully increased the lag time before breakthrough by 13–16 fold compared to HDPE alone. Calculations estimate that only 2.5–3.0% of the Fe0 initially present in the membrane reacted before breakthrough of carbon tetrachloride. Extrapolations of these results to practical situations with larger membrane thicknesses and lower contaminant concentrations predict lag times on the order of years.

Development of a Neutron Mu1tiplicity Counter System for the Nuc1ear Material Accounting and Safeguards in KAERl

A well-type neutron multiplicity counter(WNMC) system was installed in a hot cell for the purpose of nuclear material control, accounting (NMC&A) and safeguards. The WNMC system determined the nuclear material amount on the basis of the Cm-monitoring method by measuring the neutron multiplicity and the number of coincidence events. The developed system consisted of 20 He-3 tubes with a 2.54 cm diameter and 50 cm length to cover a 25 cm long uniform neutron efficiency region along the tube length direction. As a neutron moderator in order to increase the neutron absorption rate at the He-3 tube, a well type high density polyethylene(HDPE) with a 50cm diameter was used. The efficiently optimized cylindrical Cd-plate was used in order to satisfy the uniformity along the tube direction. The absolute neutron detection efficiency of the HDPE system was measured about 14.0 % and the die-away time was 51.6µs. This system will be used not only for NMC8A but also the process for material quality control, for example, decladding performance of rod-cuts and the homogeneity of a mixing powder, waste and ingot.

Improvement in the mechanical strength of asymmetric polyolefin model interfaces

The influence of two types of a styrene–ethylene/butylene–styrene (SEBS) triblock copolymer, one as received and the other functionalized with maleic anhydride, on model interfaces of high-density polyethylene (HDPE) and isotactic polypropylene (iPP) was investigated. Using a special preparation technique, it was possible to prevent gross interdiffusion at the interface and to attribute the problem to an adhesion-dominated phenomenon. The weak mechanical strength of the unmodified interfaces, iPP/iPP and HDPE/HDPE, was greatly improved by the triblock copolymer as was shown by the results of a T-peel test. The morphologies of the peeled surfaces of the modified and unmodified interfaces were analysed with light microscopy. The morphology of both model interface systems show differences, thus revealing different processes at the interfaces and thus different interactions of SEBS with iPP and HDPE and a different influence of the functionalization. The best results were achieved using the functionalized SEBS; the influence of functionalization was greater in the HDPE system. The results are in good agreement with a model proposed by the present authors elsewhere for the concentration-dependent role of SEBS in binary iPP/SEBS and ternary iPP/PE/SEBS blends.