Polyethylene Nanocomposites Research Articles

A Study on the Role of Clay Nanoparticles and Temperature on the Creep Behavior of Polyethylene Matrix Nanocomposite

Objective: In the current research, the creep behavior of polyethylene (PE) matrix nanocomposites reinforced with different content of clay nano particles (i.e., 0, 1, 3, 5, 10wt%) at different temperatures (25 and 50℃) has been investigated. Methods: In order to produce composite samples of pure PE reinforced with different percentages of clay (0, 1, 3, 5 and 10% by weight), a twin extruder was used in the temperature range of 200-230℃. Also, to produce the standard samples, an injection machine was used using in the temperature range of 220-230℃. The samples were subjected to a constant load, typically around 0.7 to 0.8 times the yield strength, at 25 and 50℃ , and at constant strain rate of 0.1min-1. Results: The creep investigations showed that for PE and its nanocomposites the creep trend could be divided into primary, secondary, and tertiary stages. The length of each stage depended strongly on both temperature and the stress level at which the samples tested as well as the clay content. It was observed that adding nano particles in small amounts (1wt%) led to an increase in the length of the creep life of PE and it also improved this property in both temperatures. Conclusion: It was observed that increasing test temperature from causes to decrease the creep strength as well as a rapid onset of plastic deformation for all materials including PE and its nanocomposites. PE nanocomposites with higher than 1wt% clay exhibited a noticeable drop in creep strength particularly at 50℃.

Superior Protection Conferred by Multi-Layered Graphene–Polyethylene Nanocomposites under Shock Loading

Superior Protection Conferred by Multi-Layered Graphene–Polyethylene Nanocomposites under Shock Loading

Dielectric studies of silica-doped barium titanate and linear low-density polyethylene nano-composite as a substrate for flexible microstrip patch antenna

Dielectric studies of silica-doped barium titanate and linear low-density polyethylene nano-composite as a substrate for flexible microstrip patch antenna

Characterization and ballistic performance of hybrid jute and aramid reinforcing graphite nanoplatelets in high-density polyethylene nanocomposites

Hybrid nanocomposites have emerged as a promising solution for engineering applications associated with reduced costs and weight aiming to enhance performance in special areas such as ballistic protection. This study delves into the development of hybrid nanocomposites featuring a high-density polyethylene matrix modified with graphite nanoplatelets and reinforced by aramid and jute fabrics. The incorporation of GNP significantly influences the crystalline structure of the GNP/HDPE matrix, as evidenced by Raman and X-ray diffraction analyses. Furthermore, it assumes an important role in modifying the crystallization and glass transition temperatures (Tc and Tg) and influencing the dynamic mechanical behavior. Specifically, it increases viscoelastic stiffness, raises the storage modulus by more than 30 %, and reduces the tanδ value. In addition, replacing 5 layers of jute fabric with an equivalent number of aramid layers maintains comparable ballistic performance to a 20-layer aramid nanocomposite. This substitution yields a remarkable 659.41 J of absorbed energy and a limit velocity of 405.72 m/s. Additionally, a hybrid nanocomposite comprising 10 layers each of jute and aramid showcases impressive ballistic resistance against 9 mm caliber ammunition, achieving 419.84 J of absorbed energy and a limit velocity of 320.13 m/s. Scanning electron microscopy analysis exposes the intricate fracture mechanisms, encompassing phenomena such as crazing, GNP/HDPE fibrillation, fiber rupture, and debonding. These mechanisms are significant in the composite's energy absorption during a projectile impact. Moreover, a cost-benefit analysis underscores the potential of hybrid nanocomposites in ballistic protection by simultaneously reducing both helmet weight and cost in 7 % and 40 %, respectively.

Isothermal crystallization kinetics of pure and surface‐modified silica/high‐density polyethylene nanocomposites

AbstractThe isothermal crystallization kinetics of high‐density polyethylene (HDPE) nanocomposites containing 0, 0.5, 0.75, and 2 wt% of pure and surface‐modified silica were evaluated at three crystallization temperatures (Tc) of 120°C, 121°C, and 122°C using differential scanning calorimetry (DSC) and applying Avrami, Tobin, and Malkin equations. According to Hoffman‐Weeks theory, the values of the equilibrium melting point () of the nanocomposites decreased with increasing nanoparticle content and were higher in the samples containing AMS nanoparticles, owing to the larger crystal. The results of all three models offered the same trend according to which the change in the crystallization temperature influenced the nucleation mechanism and the crystallization rate. It was found that a greater number of spherulites can be formed via increasing Tc from 120°C to 122°C which also decreased the crystallization rate of the nanocomposites. At the crystallization temperature of 122°C, the lowest melting temperature was recorded for the samples, attributed to the formation of more crystals with a lower thickness. Moreover, in HDPE/AMS nanocomposites, the crystallization rate was higher than that of HDPE/PSN, ascribed to the positive effect of surface modification on nanoparticles.Highlights Increased polymer/particle compatibility and isothermal crystallization. Evaluating the nucleation and crystallization using different models. The impact of isothermal crystallization temperature on crystallinity. Variation of equilibrium melting point with the nanoparticle content.

Recent advances in nitride-filled polyethylene nanocomposites

Recent advances in nitride-filled polyethylene nanocomposites

Nanocomposites of polyethylene with Fe3O4 nanoparticles via surface-initiated ROMP: Thermomechanical, shape memory and photothermal properties

The nanocomposites of polyethylene with Fe3O4 nanoparticles (NPs) were synthesized via surface-initiated ring-opening metathesis polymerization (SI-ROMP). First, the surfaces of pristine Fe3O4 NPs were functionalized with (5-nicyclo[2.2.1]hept-2-enyl)ethyl]triethoxylsilane. The as-obtained Fe3O4 NPs functionalized with norbornene were used to mediate the ROMP of cyclooctene (COE). By controlling the mass ratios of COE to the surface-functionalized Fe3O4 NPs, the polycyclooctene-grafted Fe3O4 NPs (denoted PCOE-g-Fe3O4 NPs) were obtained with variable contents of Fe3O4 NPs. Finally, these PCOE-g-Fe3O4 NPs were hydrogenated into the corresponding polyethylene-grafted Fe3O4 NPs (PE-g-Fe3O4 NPs). The nanocomposites of PE with Fe3O4 NPs were successfully synthesized as evidenced by the morphologies that the Fe3O4 NPs were well dispersed in PE matrix at the scale of nanometer. The nanocomposites displayed the mechanical properties superior to plain PE. More importantly, the nanocomposites were capable of displaying superparamagnetic, thermally-induced shape memory and photothermal properties. Furthermore, the photothermal behavior can be utilized to trigger the shape memory properties in a non-contact fashion.

Analysis of interfacial characteristics in polymer nanocomposites via visual particle recognition methodology and micromechanical predictive models

This study examines the morphological features of nano-zeolite nanoparticles incorporated into ultra-high molecular weight polyethylene nanocomposites, known for their excellent biocompatibility and significant potential in structural biomedical applications. The analyses involved qualitative assessments and a statistical approach based on visual particle recognition technique. Scanning electron microscopy was adopted for morphological assessments of impact-fractured surfaces. The scanning electron microscopy observations unveiled the improved dispersion of nanoparticles within the polymer matrix following nano-zeolite incorporation. In the quantitative approach, the nanoparticles size and distribution were systematically determined through tailored histograms, utilizing the customized particle recognition strategy applied to images. This analysis yielded average particle sizes for each composite, further used for calculating the effective elastic moduli of nanocomposites by employing a two-fold micromechanics-based homogenization technique, accounting for interfacial effects. The computation of average particle size based on visual measurements substantially improved the accuracy regarding the quantitative analysis of interphase effects on macroscopic properties, marking a departure from the conventional practice of conducting such calculations by relying on unrealistic particle sizes based on their as-received values before compounding with the polymer.

Characterization and experimental investigation for gamma–ray shielding competence of basalt-doped polyethylene nanocomposites

Experimental investigations on gamma - rays attenuation parameters and dielectric spectroscopic properties were done on a polymeric mixture with chemical composition (100-x) polyethylene + x basalt, where x = 0, 1, 3, 5, 10, and 20 wt%. Using the melting blending technique,six nanocomposite polymeric samples were prepared. The linear attenuation coefficient μ of each prepared set of samples was measured using a gamma-ray spectrometer including High Purity Germanium detector (HPGe) at energies 662.5, 1173.24, and 1332.51 keV. Based on the measured values of (μ) and sample density, the other effective shielding parameters were calculated. the values of μ showed an increase with increasing the dopant ratios from 0.0 up to 20.0 wt%. In addition, the μ values decreased with the photon's energy. The μ values were found 0.0847 up to 0.1175 cm−1, 0.0571 up to 0.0855 cm−1, and 0.0543 up to 0.075 cm−1 at 662.5, 1173.24, and 1332.51 keV. for B0 up to B20, respectively. The ATR spectroscopy was done on the prepared samples, and a good evidence of adding the filler to the pure polyethylene (HDPE) was obtained. Besides, an enhancement in dielectric constant by insertion of basalt NPs also recorded and can be attributed to the large dielectric constant of basalt compared to pure HDPE.

Synthesis and Characterization of polyethylene/Metal Organic Framework Nanocomposites: enhanced thermal stability and crystallinity through UiO-66 Nanofiller incorporation

ABSTRACT This study focused on the synthesis and characterization of polyethylene/metal organic framework (MOF) nanocomposites. UiO-66, a metal organic framework nanoparticle, was synthesized using a hydrothermal method and incorporated as a drop-in filler during in-situ polymerization of ethylene with a Zirconocene/modified methyl aluminoxane (MMAO) catalytic system. The use of in-situ polymerization allowed for excellent dispersion of the fillers within the polyethylene matrix. The impact of UiO-66 nanomaterials on the thermal, crystalline, and morphological properties of the resulting polyethylene nanocomposites was investigated, alongside their effect on catalytic activity. The MOF-filled polyethylene nanocomposites exhibited enhanced thermal stability with a temperature value of 460.1°C at 10% weight loss (T0.9) and crystallinity (90.8%) compared to neat polyethylene with T0.9 of 447°C and crystallinity of 82.5% respectively while maintaining the rest of the properties of the composites. These findings highlight the potential of MOF (UiO-66) based nanofillers in improving the overall performance of polyethylene-based nanocomposites.

Effect of magnesium hydroxide and graphene nanoplatelets on the properties of peroxide cross‐linked linear low‐density polyethylene nanocomposite

AbstractLinear low‐density polyethylene (LLDPE) and different concentrations (5‐20 wt%) of magnesium hydroxide (MAH) as a filler either with or without the addition of graphene nanoplatelets (GNPs) were peroxide cross‐linked using dicumyl peroxide as a cross‐linking agent in a twin‐screw extruder. The mechanical, thermal stability, flame retardancy, morphological, and rheological properties of the prepared samples were investigated. The mechanical properties of the peroxide cross‐linked LLDPE samples with higher MAH and GNP in the matrix were significantly improvement compared to neat LLDPE. This indicates that the addition of MAH and GNP to the peroxide cross‐linked LLDPE matrix could be suitable reinforcing fillers to achieve better and enhanced mechanical properties, particularly tensile strength. Conversely, a significant decrease in the elongation at break values was found for peroxide cross‐linked LLDPE samples compared to neat LLDPE. Similarly, results of thermogravimetric analysis revealed remarkable thermal stability enhancement in the peroxide cross‐linked LLDPE samples with higher MAH and GNP compared to neat LLDPE. The results from UL94 test demonstrated that the peroxide cross‐linked LLDPE samples comprising higher MAH with GNP exhibited improved V = 0 rating compared to poor no rating (NR) for neat LLDPE. Furthermore, the scanning electron microscope and digital images shown improved flame retardancy properties for these samples because of the formation of protective char layer on the sample surface. The complex viscosity for the peroxide cross‐linked LLDPE samples, at lower frequency, increased with increasing MAH loading and further addition of GNP compared to neat LLDPE.Highlights Cross‐linked polyethylene with flame retardant (FR) and nanofiller were prepared. Effects of cross‐linking and FR on the final properties of the polymer were studied. 20wt% FR with 3 phr nanofiller promoted the final properties of the polymer. Higher filler loading in the polymer improved flame retardancy and thermal stability. Combined effect of cross‐linking and FR has shown major improvement.

Monte Carlo simulation of the crystallization of polyethylene nanocomposites with different shape nanofillers

Monte Carlo simulation of coarse-grained models of polyethylene (PE) nanocomposites was developed to study the effect of nanofiller shapes (nanosphere, nanoplate and nanostick) on the early stage of polymer crystallization under stepwise cooling from the melts. The “polymer forcefield” to describe intra- and intermolecular interaction is composed of the rotational isomeric state (RIS) model of PE and the Lennard-Jones (LJ) potential energetics of ethylene units, respectively. Carbon-based nanofillers were used such that polymer-nanofiller interaction was treated using the same LJ parameters as polymer–polymer interaction. The content of trans conformation and the chain/bond order parameter were determined to quantify the degree of polymer crystallization. Simulation suggests that PE nanocomposites filled with nanostick and nanoplate tend to induce earlier crystalline formation and have more ordered structures, especially nanocomposites with nanoplate filler. In contrast, PE nanocomposites filled with nanosphere exhibit slower crystallization with a lower amount of trans fraction and, as a result, form less ordered structures.

Solid-Phase Production of Low-Density Polyethylene Compositions with Reduced Graphene Oxide under Shear Deformations

Nanocomposites of low-density polyethylene (LDPE) with a nanocarbon nanofiller, reduced graphene oxide (RGO) of different composition, have been obtained under conditions of high-temperature shear deformations in a rotary disperser. Structure and properties of the obtained nanocomposites have been studied using a wide range of physico-chemical methods of analysis, including laser diffraction, scanning electron microscopy, and measurement of mechanical and electrical parameters. The influence of the components ratio in the compositions on the characteristics of the resulting materials has been demonstrated.

Negative Capacitance in Nanocomposite Based on High-Density Polyethylene (HDPE) with Multiwalled Carbon Nanotubes (CNTs).

Negative capacitance (NC), already observed in conducting polymer-based nanocomposites, was recently reported and evidenced at low frequencies (<10 kHz) in non-conducting polymer-based nanocomposites containing conductive particles. In this contribution, we demonstrate that it is possible to produce economic high-density polyethylene (HDPE) nanocomposites exhibiting an NC effect at low frequencies via a convenient and environmentally friendly extrusion-like process by only adjusting the duration of melt-mixing. Nanocomposite materials are produced by confining a limited quantity, i.e., 4.6 wt.%, of multiwalled carbon nanotubes (CNTs) within semi-crystalline HDPE to reach the percolation threshold. With increasing melt processing time, crystallites of HDPE developing at the surface of CNTs become bigger and perturbate the connections between CNTs leading to a dramatic change in the electrical behavior of the systems. More specifically, the link between NC and current oscillations is stressed while the dependence of NC with the size of polymer crystallites is evidenced. NC tends to appear when space charge effects take place in HDPE/MWCNT interfaces, in structures with convenient crystallite sizes corresponding to 10 min of melt-mixing.

Improved rheological, barrier, antibacterial, and electromagnetic interference shielding properties of graphene and graphene derivatives based linear low density polyethylene nanocomposites

AbstractMultifunctional polymer/graphene based lightweight and flexible nanocomposite films are increasingly being utilized in the packaging, electronics, and pharmaceutical industries together. Herein, two graphene derivatives: silver nanoparticle decorated reduced graphene oxide (G‐Ag) and chemically reduced graphene oxide (rGO) prepared by wet chemical method and graphene nanoplatelets (GNP) have been incorporated into linear low density polyethylene (LLDPE) thermoplastic matrix via melt compounding method. The incorporation of graphene derivatives affected the physico‐mechanical, electrical and thermal conductivity, and barrier properties (both oxygen and water vapor permeability) of the nanocomposite films. With 5 wt% of G‐Ag, rGO, and GNP loading, the thermal conductivity of these three nanocomposite films was enhanced by an average of 136.7%, 123%, and 143.3%, respectively. Graphene having high specific surface area and aspect ratio allow for a tortuous passage of oxygen and water molecules through the nanocomposite film, ultimately improving both oxygen and water vapor impermeability qualities for all LG‐Ag, LrGO, and LGNP nanocomposites. Moreover, the films have been tested against both gram‐positive and gram‐negative bacteria to ensure their bactericidal activity. The prepared composite films also showed Electromagnetic Interference (EMI) shielding effectiveness (−21, −17, and −19 dB) higher than the commercial cut‐offs. The thermoplastic nanocomposite films with promising thermal conductivity might be an excellent choice for bacteria‐resistant and barrier‐capable packaging and efficient thermal management EMI shields in electronics.

Molecular Simulation of the Crystallization of Polyethylene Nanocomposites: The Effect of Surface Affinity of Nanofillers

AbstractMonte Carlo simulation of coarse‐grained models is used to investigate the effect of polymer–nanofiller interaction on the structural formation of polyethylene nanocomposites with stepwise cooling from the melts. Polyethylene (PE) is represented by the rotational isomeric state (RIS) model and the Lennard–Jones potential function for intrachain energetics and non‐bonded interactions, respectively. Crystallization is monitored using the fraction of trans state and the orientation order parameter at bond and chain scale. The results show that PE nanocomposites with repulsive polymer–surface interaction can enhance faster structural formation and induce larger degree of the ordered structures. On the other hand, nanofiller with attractive polymer–surface interaction causes the chain with lower amount of trans conformation resulted in less ordered structures.

Mechanical, thermal, and morphological properties of low-density polyethylene nanocomposites reinforced with montmorillonite: Fabrication and characterizations

Nanoparticle incorporation in polymeric matrices to generate polymer nanocomposite with the intention of maximizing the “nano-effect” derived from the nanoparticles and minimizing the drawbacks of the polymer is an emerging field of research. In this study, low-density polyethylene (LDPE) was mixed with varying concentrations of montmorillonite (MMT) nanoclays to create a polymer nanocomposite with desirable characteristics. Composite sheets with nanoclays contents of (0, 1, 2, 3, and 4 wt%) were prepared for hardness, tensile-fractography, thermal conductivity, and tensile testing (elongation and stress-at-break). The results showed that, according to scanning electron microscope (SEM) study, LDPE has a low flexibility temperature and is prone to corrosion. For larger MMT filler loadings (>3% wt), tensile-fractography showed nanoclays particle micro-aggregation. The pure LDPE sample fracture’s tensile-fractography showed plastic deformation. MMT/LDPE samples with 3% wt hard MMT filler have brittle fractures without appreciable plastic deformation. Thermal conductivity test results show that LDPE/MMT composite thermal conductivity decreased with increasing clay concentration. The thermal conductivity values were reduced from a value of 0.13 W/m.K to a value of 0.039 W/m.K when reinforced with 0% wt to 3% wt filler loading, respectively. With 4% wt filler loading, LDPE/MMT composites had the highest shore hardness at 47.4. Yet, tensile tests indicated that increasing clay content improved the composite’s characteristics. At modest loading percentages (1–2 wt%), tensile results were excellent. Furthermore, the elongation at break of the unadulterated LDPE was reduced by 20% and 30% after introducing 1% wt and 2% wt of MMT as reinforcement additives, respectively. Hence, MMT clay can improve the mechanical properties and thermal insulation of LDPE polymer matrix.

Emerging hybrid particle-reinforced high-density polyethylene nanocomposite for bone replacement

Emerging hybrid particle-reinforced high-density polyethylene nanocomposite for bone replacement

Preparation of Polyethylene/α-Zirconium Phosphate Nanocomposites via a Well-Controlled Polyethylene-Grafted Interface.

It is a daunting task to prepare polyolefin nanocomposites that contain well-exfoliated nanoplatelets due to the nonpolar and high crystallinity nature of polyolefins. In this research, a robust approach was developed to prepare polyethylene (PE) nanocomposites by grafting maleated polyethylene (MPE) onto pre-exfoliated α-zirconium phosphate (ZrP) nanoplatelets via a simple amine-anhydride reaction to form ZrP-g-MPE. Several variables, including maleic anhydride (MA) content, MPE graft density, MPE molecular weight, and PE matrix crystallinity, were investigated to determine how they influence ZrP-g-MPE dispersion in PE. It was found that grafted PE has a different morphology and that the long PE brushes with medium graft density on ZrP can achieve sufficient chain entanglement and cocrystallization with PE matrix to stabilize and maintain ZrP-g-MPE dispersion after solution or melt mixing. This leads to enhanced Young's modulus, yield stress, and ductility. The structure-property relationship of PE/ZrP-g-MPE nanocomposites and usefulness of this study for the preparation of high-performance polyolefin nanocomposites are discussed.

Impact of Proton Irradiation on Medium Density Polyethylene/Carbon Nanocomposites for Space Shielding Applications.

The development of novel materials with improved radiation shielding capability is a fundamental step towards the optimization of passive radiation countermeasures. Polyethylene (PE) nanocomposites filled with carbon nanotubes (CNT) or graphene nanoplatelets (GNP) can be a good compromise for maintaining the radiation shielding properties of the hydrogen-rich polymer while endowing the material with multifunctional properties. In this work, nanocomposite materials based on medium-density polyethylene (MDPE) loaded with different amounts of multi-walled carbon nanotubes (MWCNT), GNPs, and hybrid MWCNT/GNP nanofillers were fabricated, and their properties were examined before and after proton exposure. The effects of irradiation were evaluated in terms of modifications in the chemical and physical structure, wettability, and surface morphology of the nanocomposites. The aim of this work was to define and compare the MDPE-based nanocomposite behavior under proton irradiation in order to establish the best system for applications as space shielding materials.