High Density Polyethylene Nanocomposites Research Articles

Enhancing Mechanical Performance of High-Density Polyethylene at Different Environmental Conditions with Outstanding Foamability through In-Situ Rubber Nanofibrillation: Exploring the Impact of Interface Modification.

In this study, we utilized in situ nanofibrillation of thermoplastic polyester ether elastomer (TPEE) within a high-density polyethylene (HDPE) matrix to enhance the rheological properties, foamability, and mechanical characteristics of the HDPE nanocomposite at both room and subzero temperatures. Due to the inherent polarity differences between these two components, TPEE is thermodynamically incompatible with the nonpolar HDPE. To address this compatibility issue, we employed a compatibilizer, styrene/ethylene-butylene/styrene copolymer-grafted maleic anhydride (SEBS-g-MA), to reduce the interfacial tension between the two blend components. In the initial step, we prepared a 10% masterbatch of HDPE/TPEE with and without the compatibilizer using a twin-screw extruder. Subsequently, we processed the 10% masterbatch further through spun bonding to create fiber-in-fiber composites. Scanning electron microscopy (SEM) analysis revealed a significant reduction in the spherical size of HDPE/TPEE particles following the inclusion of SEBS-g-MA, as well as a much smaller TPEE nanofiber size (approximately 60-70 nm for 5% TPEE). Moreover, extensional rheological testing revealed a notable enhancement in extensional rheological properties, with strain-hardening behavior being more pronounced in the compatibilized nanofibrillar composites compared to the noncompatibilized ones. SEM images of the foam structures depicted substantial improvement in the foamability of HDPE in terms of the cell size and density following the nanofibrillation process and the use of the compatibilizer. Ultimately, the in situ rubber fibrillation and enhancement of HDPE and TPEE interface using a compatibilizer led to increasing the HDPE ductility at room and subzero temperatures while maintaining its stiffness.

Exploring the Effects of Nano-CaCO3 on the Core-Shell Structure and Properties of HDPE/POE/Nano-CaCO3 Ternary Nanocomposites.

To address the dilemma of the stiffness and toughness properties of high-density polyethylene (HDPE) composites, titanate coupling agent-treated CaCO3 nanoparticles (nano-CaCO3) and ethylene-octene copolymer (POE) were utilized to blend with HDPE to prepare ternary nanocomposites via a two-sequence-step process. Meanwhile, a one-step process was also studied as a control. The obtained ternary nanocomposites were characterized by scanning electron microscopy (SEM), Advanced Rheometrics Expansion System (ARES), Dynamic Mechanical Analysis (DMA), wide-angle X-ray diffraction analysis (WXRD), and mechanical test. The SEM results showed one or two CaCO3 nanoparticles were well-encapsulated by POE and were uniformly dispersed into the HDPE matrix to form a core-shell structure of 100-200 nm in size by the two-step process, while CaCO3 nanoparticles were aggregated in the HDPE matrix by the one-step method. The result of the XRD showed that the nano-CaCO3 particle played a role in promoting crystallization in HDPE nanocomposites. Mechanical tests showed that the synergistic effect of both the POE elastomer and CaCO3 nanoparticles should account for the balanced performance of the ternary composites. In comparison with neat HDPE, the notched impact toughness of the ternary nanocomposites of HDPE/POE/nano-CaCO3 was significantly increased. In addition, the core-shell structure absorbed the fracture impact energy and prevent further propagation of micro-cracks, thus obtaining a higher notched Izod impact strength.

Effective Utilization of Bast Fiber in High Density Polyethylene Nanocomposite Enriched by Alumina Nanoparticle: Mechanical Performance Evaluation

Effective Utilization of Bast Fiber in High Density Polyethylene Nanocomposite Enriched by Alumina Nanoparticle: Mechanical Performance Evaluation

Structural Characteristics and Improved Thermal Stability of HDPE/Calcium Pimelate Nanocomposites

In the present research work, calcium pimelate (CaPim) was synthesized and investigated as an additive for high-density polyethylene (HDPE). HDPE/CaPim nanocomposites were prepared by melt-mixing, with CaPim content ranging from 0.1% to 1%, affording white homogeneous materials. The chemical structure of the nanocomposites and the incorporation of CaPim was confirmed by infrared spectroscopy. The surficial morphology and the additive distribution were examined by scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction measurements showed that the thermal transitions and crystal structure of HDPE are not affected by the incorporation of CaPim, while the mechanical properties are retained overall. This study focuses on the thermal degradation of HDPE nanocomposites, investigating the degradation mechanism and kinetic parameters through various analytical methods. Isoconversional techniques, including the Friedman method, Vyazovkin analysis, and Ozawa Flynn Wall analysis, were employed to calculate activation energies (Eα). The degradation mechanism and kinetic triplet were determined based on a multivariate non-linear regression method (model-fitting). Finally, the presence of a CaPim additive was shown to increase the Eα of thermal degradation, consistent with the calculated dependence of Eα on the degree of conversion and the improved thermal stability of the HDPE matrix.

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.

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.

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

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

Dynamic Fracture Resistance under Plane Strain Conditions of High-Density Polyethylene Nanoclay Composites.

Polymer nanoclay composites have received significant attention due to their substantially enhanced mechanical, thermal and barrier properties. However, the effect of these nanoclays on the dynamic fracture resistance of a polymer matrix during fast fracture events has not been documented. In this study, the effect of nanoclay addition on the rapid crack propagation (RCP) resistance of high-density polyethylene (HDPE) was investigated through the high-speed double torsion test. Results showed that the addition of 1, 3, and 5% of nanoclays improved the dynamic fracture resistance under the plane strain conditions (Gd1) of HDPE up to 65%. An increase in the storage and loss modulus, and a decrease in crystallinity and melt flow index with nanoclay content was also found. Although the presence of agglomerates can hinder the enhancement of Gd1 as it promotes agglomerate fracture and debonding, the increase in energy consumption through fibrillation and crazing promoted by the nanoclay prevails, suggesting that the nanoclay's toughening effect that has been extensively reported under quasi-static and impact tests, is also present under RCP conditions, and that the HDPE nanocomposites could be used in applications in which RCP must be prevented.

A study on the synergetic effects of self/induced crystallization and nanoparticles on the mechanical properties of semi-crystalline polymer nanocomposites: experimental and analytical approaches

This work investigates the effects of nanoparticle content, aggregation/agglomeration, polymer/particle interphase, and crystallinity on the mechanical properties of high-density polyethylene (HDPE) nanocomposites. Different samples of HDPE nanocomposites, containing 0.5, 0.75, and 2 wt% of pure and surface-modified silica nanoparticles were prepared by melt-mixing method. The pure silica nanoparticles (PSN) and surface-modified silica nanoparticles with (3-aminopropyl) tri-ethoxy-silane (AMS) were characterized with field emission scanning electron microscopy (FESEM) and Fourier-transform infrared (FTIR) spectra. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to estimate the crystallinity and crystal size of the nanocomposite samples. Finally, tensile testing was performed on the nanocomposites to establish the relationship between mechanical properties and nanoparticle loading, and surface modification. The results indicate that the crystallinity and elastic modulus of the nanocomposites increased with increasing nanoparticle content. Moreover, the Gutzow–Dobreva theory was applied to approximate the degree of the induced crystallinity in each sample. A mechanical model based on two equivalent box models (EBM) was proposed to determine the crystalline, amorphous phase modulus, thickness and tensile modulus of the polymer/particle interphase region, which showed a decreasing trend with the nanoparticles content and indicated that this region was thicker for the HDPE/AMS relative to HDPE/PSN. Also, it was found that nanoparticles affected both crystalline and amorphous sections, which their effect on the crystals was more significant and presence of the well-dispersed nanoparticles in the amorphous section substantially enhanced their performance against the exerted stress.

Calculation of the degree of crystallinity of HDPE/GNPs nanocomposites by using various experimental techniques: a comparative study

This work is a comparative study of four different techniques to determine the crystallinity of high-density polyethylene (HDPE) nanocomposites filled with different diameter sizes (5, 15 and 25 μm) of graphene nanoplatelets (GNPs) at various amounts (0.5–5 wt%). The structure of HDPE/GNPs nanocomposites was extensively studied by using different experimental methods, such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. To further provide a complete comparison, differential scanning calorimetry measurements were utilized to calculate the crystallinity values, while temperature-modulated DSC was employed to investigate the possible mechanism of the different crystalline structures. It was found that these methods can be used to estimate the crystallinity, but the sample parameters and experimental conditions must be taken into consideration. All the techniques showed that the crystallinity depends on GNPs size and content. The distance between dispersed platelets was substantial at low concentrations of GNPs, making it comparatively easy for additional nucleation sites to incorporate the polymer matrix, and the crystal nucleus was simply formed. However, at high concentrations of GNPs, the diffusion of polymer chains to the growing crystallites was hindered by large GNPs particles, despite the formation of additional nucleation sites.

Positive/Negative Temperature Coefficient Behaviors of Electron Beam-Irradiated Carbon Blacks-Loaded Polyethylene Nanocomposites.

Polymer-based materials with positive temperature coefficients (PTC) are regarded as potential candidates for electrical heating elements in a wide range of applications, such as wearable electronics, soft robots, and smart skin. They offer many advantages over ceramic or metal oxide-based composites, including low resistance at room temperature, excellent flexibility and processability, and low cost. However, the electrical resistance instability and poor reproducibility have limited their use in practical applications. In this work, we prepared carbon blacks-reinforced high-density polyethylene nanocomposites (CBs-HDPE) loaded with polar additives (polyols or ionomers), which were subsequently subjected to electron beam (EB) irradiation to explore their PTC behaviors. We found that the EB-treated nanocomposites exhibited PTC behaviors, while the untreated samples showed negative temperature coefficients. Further, EB-ionomer-CBs-HDPE showed the highest PTC intensity of 3.01 Ω·cm, which was ∼35% higher than that of EB-CBs-HDPE. These results suggested that the EB irradiation enabled a specific volume expansion behavior via enhanced crosslinking among CBs, polar additives, and HDPE, inhibiting the formation of conductive networks in the nanocomposites. Thus, it can be concluded that polar additives and further EB irradiation played an important role in enhancing the PTC performances. We believe the findings provide crucial insight for designing carbon-polymer nanocomposites with PTC behaviors in various self-regulating heating devices.

Compressive behavior of 3D printed MWCNT/HDPE nanocomposites

The current work investigates the compressive behavior of three-dimensional (3D) printed functionalized MWCNTs (multi-walled carbon nanotubes)/HDPE (high-density polyethylene) nanocomposite (NC) samples. The NCs are prepared by varying functionalized MWCNTs in the proportion of 0.5–5 wt. (weight) % in HDPE through compounding. The NC pellets are further used for extruding feedstock filaments to be used in fused filament fabrication based 3D printer. The crystallinity of NC filaments and prints is higher than HDPE filaments and prints respectively. The compressive modulus, yield strength, and the peak stress of the prints are observed to be increasing, whereas the energy absorption is observed to be decreasing with functionalized MWCNTs loading.

MEX 3D Printed HDPE/TiO2 Nanocomposites Physical and Mechanical Properties Investigation

Aiming to develop more robust, mechanically advanced, Fused Filament Fabrication (FFF) materials, High-Density Polyethylene (HDPE) nanocomposites were developed in the current research work. Titanium Dioxide (TiO2) was selected as filler to be incorporated into the HDPE matrix in concentration steps of 0.5, 2.5, 5, and 10 wt.%. 3D printing nanocomposite filaments were extruded in ~1.75 mm diameter and used to 3D print and test tensile and flexion specimens according to international standards. Reported results indicate that the filler contributes to increasing the mechanical strength of the virgin HDPE at certain filler and filler type concentrations; with the highest values reported to be 37.8% higher in tensile strength with HDPE/TiO2 10 wt.%. Morphological and thermal characterization was performed utilizing Scanning Electron Microscopy (SEM), Raman, Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), while the results were correlated with the available literature.

Mechanical characterization of 3D printed MWCNTs/HDPE nanocomposites

The development of polymer nanocomposite blends using multi-walled carbon nanotubes (MWCNTs) and high-density polyethylene (HDPE) is presented in this paper. Fused Filament Fabrication (FFF) based 3D printer is used to realize MWCNT (0.5, 1, 3, and 5 by wt. %)/HDPE nanocomposite (NC) 3D printed samples. The addition of MWCNT increases TCryst, αCryst and TMelt. Thermogravimetric analysis (TGA) of neat HDPE and MWCNT/HDPE NCs is also carried out to check their thermal stability at higher working temperatures. The degradation temperature of MWCNT/HDPE NCs is observed to be higher than neat HDPE and increasing with MWCNT content. The filaments are tested for tensile, while specimens are tested for both tensile and flexural properties. It is observed that tensile and flexural modulus and strength improve with increasing MWCNT. Finally, the results of the tensile tested specimens are compared to those of various HDPE composites found in the literature.

Mechanical and Morphological Properties of Fluted Pumpkin Stem Fiber (Telfaira occidentalis) Recycled High Density Polyethylene Nanocomposites

The outstanding characteristic properties of nanographene such as high aspect ratios and improved mechanical properties in comparison with other types of nanofillers like carbon nanotubes and clays has accelerated their use as nanosize filler in polymer matrix composites. The litter of agro-wastes is a critical issue which must be addressed for the preservation of the global environment. The effect of nanographene addition on the mechanical and morphological properties of nanocomposites prepared using fluted pumpkin stem fiber (FPF) and recycled high density polyethylene (R-HDPE) was investigated. Four weight levels of nanographene 0, 0.5, 1.5 and 2.5 wt % were mixed with 65 wt. % HDPE, 35wt. % FPF and 3wt% maleic acid anhydride produced using melt compounding and the extruded nanocomposites was shaped by injection molding machine for the mechanical tests. The results showed that addition of 0.5 wt % nanographene increased the flexural strength, flexural modulus and notched impact strength by 24.77MPa, 1800MPa and 32.61J/m2, compared to the control samples 20.5MPa, 1500MPa and 19.35J/m2 respectively. Although the addition of nanographene to the FPF/HDPE composite significantly improved the flexural strength, flexural modulus and notched impact strength, these improvements came at a unique nanographene loading of 0.5 wt %. The morphological images revealed that the samples with nanographene loading of 0.5 wt. % showed no fiber pullout/holes, whereas higher contents (1.5-2.5wt %) of nanographene exhibited fiber pullout/holes and were easily agglomerated. This study has shown that fluted pumpkin stem fiber could be used in composite formulation with good results comparable to wood-plastic-composites.

Exploring the mechanical performance of BaTiO3 filled HDPE nanocomposites: A comparative study of the experimental and numerical approaches

The mechanical behavior of BaTiO 3 incorporated High-Density Polyethylene (HDPE) nanocomposites up to 40% in volume is investigated experimentally through tensile tests. The results showed that Young's modulus increased with increasing amount of BaTiO 3 particles, indicating a higher stiffness. A numerical approach based on a micromechanical model showed the same trend, but with values lower than the experimental ones for all the composite concentrations. The influence of the particle distribution (uniform or random) in the Representative Volume Element (RVE) as well as the RVE size were particularly investigated. The effect of the strain and strain rate on the Young's modulus was highlighted experimentally and numerically. The influence of the filler particles on the strain and stress field distributions in RVE was shown to be a key parameter in the mechanical response of the nanocomposites and revealed the necessity to take into account the true behavior of HDPE in the numerical modeling. • Numerical approach to understand the modification of mechanical properties of barium titanate filled HDPE. • Influence of filler particles on Young's modulus of composites studied by experimental and numerical approaches. • True mechanical behavior of HDPE in the HDPE matrix composites. • Focus on the strain and strain rate on the mechanical properties of the BaTiO 3 -HDPE nanocomposites. • Emphasizing on the stress and strain field distributions on the mechanical behavior of composites emphasized by numerical approach.

Barrier properties of nanocomposites from high-density polyethylene reinforced with natural attapulgite

Attapulgite (ATT) has never been used as a barrier additive incorporated into polymers; instead, it has mostly been applied as a reinforcement or a nucleator. But ATT is very suitable as barrier additives in polymer materials because it can adsorb gas or water by virtue of its porous structure. In this study, ATT nanomaterials from natural minerals were purified and added to high-density polyethylene (HDPE) to prepare HDPE/ATT nanocomposites. The influence of a low content of ATT on the mechanical properties, crystallinity, morphology, water absorption, hydrophilicity, thermostability, and barrier properties of HDPE nanocomposites was analyzed. The results showed that adding a small amount of ATT could improve the mechanical properties, crystallinity, thermal stability, hydrophobicity, and barrier properties, but excessive amounts of it would reduce the mechanical and barrier properties. X-ray diffraction results showed that with increase in the ATT content, the peak did not significantly change and the nanocomposite material was mainly crystalline. According to the oxygen permeability test analysis, the oxygen barrier performance of the nanocomposite material was optimal when ATT was 0.4%. This great improvement in barrier performance might be ascribed to two reasons: (1) The presence of ATT extended the penetration path of molecules; (2) ATT itself had a porous structure, and molecules may be adsorbed and stored in it. Therefore, the addition of ATT led to good performance of HDPE nanocomposites, and this would lead to broad application prospects, which would be worthy of further study.

Effect of Polyethylene Structure on the Properties of Carbon Nanotube/Polyethylene Composites

The influence of polyethylene (PE) molecular structure on multi-walled carbon nanotubes (MWCNT)/PE composites processing behavior and their thermal, rheological and electrical properties were investigated. Two different types of PE of almost the same viscosity were investigated; namely, high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Nanocomposites filled with up to 10 wt.% MWCNT were prepared by the conventional melt-mixing method. The MWCNT exhibited better dispersion in HDPE than in LDPE. The crystallinity of the HDPE marginally increased with the addition of the MWCNT, while no significant influence of the MWCNT on the LDPE crystallinity was observed. The AC electrical conductivity of both the HDPE and LDPE nanocomposites were almost the same. Thus, we concluded that there is no significant effect of the PE structure on the formation of the MWCNT networks.

Cavitation in strained polyethylene/nanographene nanocomposites

Cavitation in nanocomposites of high-density polyethylene (HDPE) with either graphene nanoplatelets (G) or reduced graphene oxide (rGO) during tensile deformation and impact tests was studied. Composites of HDPE containing 0.1, 0.3, 0.5, and 1 wt% of G (HDPE + G) or rGO (HDPE + rGO) were processed using a twin-screw extruder. Scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), Izod impact tests, tensile drawing and differential scanning calorimetry (DSC) were used to study HDPE + G and HDPE + rGO nanocomposites. The effects of G and rGO contents on the thermal and mechanical properties of composites were investigated. The inclusion of G platelets in the matrix increased the onset temperature of nonisothermal crystallization of HDPE while inclusions of rGO did not. It was shown that during tensile drawing cavitation occurs in the nanocomposites and HDPE alone. The cavitation pores have sizes above 25 nm with the bias towards larger pores for both types of the nanocomposites. Smaller pores were healed due to the surface tension. In Izod tests the debonding of HDPE from the nanoplatelets occurred ahead of the traveling Izod crack tip giving rise to many voids becoming centers from which fracture emanated radially until impingement. There is only a small difference between HDPE + G and HDPE + rGO nanocomposites: G nanoplatelets nucleate the crystallization of HDPE.

Investigation on the Thermoforming of Pmsq-Hdpe for the Manufacture of a NACA Profile of Small Dimensions.

Unmanned aerial vehicles (UAVs) or drones are attracting increasing interest in the aviation industry, both for military and civilian applications. The materials used so far in the manufacture of UAVs are wood, plastic, aluminum and carbon fiber. In this regard, a new family of high-density polyethylene (HDPE) nanocomposites reinforced with polymethylsilsesquioxane nanoparticles (PMSQ), with mechanical performances significantly superior to those of pure HPDE, has been prepared by a fusion-combination process. Their viscoelastic properties were determined by oscillatory shear tests and their viscoelastic behavior characterized by the Lodge integral model. Then, the Lagrangian formulation and the membrane theory assumption were used in the explicit implementation of the dynamic finite element formulation. For the forming phase, we considered the thermodynamic approach to express the external work in terms of closed volume. In terms of von Mises stress distribution and thickness in the blade, the results indicate that HDPE-PMSQ behaves like virgin HDPE. Furthermore, its materials, for all intents and purposes, require the same amount of energy to form as HDPE.