High-density Polyethylene Matrix Research Articles

Influence of exfoliation method of graphene on physical properties of graphene/High Density Polyethylene nanocomposites: Semiconductor‐like electrical conductivity, glass transition, and melting temperature

AbstractDespite the wide range of applications of polyethylene (PE), many efforts are being made to improve its properties with carbon allotropes such as graphene. The addition of graphene can improve the electrical, thermal, and mechanical properties of this polymer. Through the present study, the effects of exfoliated graphene nanoplatelets (XGNPs) and few‐layer graphene (FLG) on the electrical conductivity and thermal properties of high‐density polyethylene (HDPE) were investigated. XGNPs were synthesized by ultrasonication of graphite nanoplatelets, and FLG was synthesized by shear exfoliation of flake graphite. Finally, HDPE powder particles were coated with dispersed XGNPs and FLG. Then XGNPs/HDPE nanocomposites and FLG/HDPE nanocomposites were fabricated by compression molding. The morphology, structural, electrical, and thermal properties of the graphite, graphene, PE, and nanocomposites were observed and comparatively studied by transmission electron microscopy, field emission scanning electron microscope, x‐ray diffraction (XRD), Raman spectroscopy, and conductivity measurements. The graphene's D, G, and 2D bands were revealed by Raman spectroscopy of nanocomposites and verified the existence of the graphene in the polymer matrix. XRD revealed that the graphene did not affect the original crystalline structure of the HDPE matrix, and the Fourier‐transform infrared spectroscopy revealed that the nanocomposite was obtained without the formation of any functional groups. The electrical properties of the nanocomposites were comparatively studied. After adding XGNPs (7 wt%), volumetric electrical conductivity in a sample reached from 10−16 to 10−3 S/m. The highest volumetric conductivity, 1.1 × 10−2 S/m, that is, semiconductor‐like conductivity, was achieved after adding 7 wt% of FLG. The glass transition temperatures (Tg), melting temperatures (Tm), and thermal stability were investigated by differential scanning calorimetry and TGA, respectively, and it was concluded that Tg and Tm increase by adding the graphene. This study shows that shear exfoliation of graphene is the best and the most facile method to prepare mass‐scale graphene for the production of graphene/polyolefin nanocomposites.Highlights Two types of graphene were produced by using sonication and shear‐exfoliation. HDPE powders were coated with two types of graphene and then hot pressed. The method of (G) preparation is crucialparameter on electrical conductivity. In the sample containing 7 wt% (XGNPs), the highest conductivity is 10−3 S/m. In the sample containing 7 wt% (FLG), the highest conductivity is 10−2 S/m.

EFFECTS OF NATURAL FIBERS ON THE COMPRESSIVE STRENGTH PROPERTIES OF HDPE MATRIX COMPOSITES

The current research reveals the synergistic effect of different ratios of natural fiber concentration and maleic anhydride grafted polyethylene (PE-g-MA) compatibilizer on the compressive strength properties of high density polyethylene (HDPE) matrix composites. Composites containing flax (FF) and palm (PF) short fibers with different weight ratios were processed by melt blending and then compression tests were performed at a compression speed of 2 mm/min. As a result of the tests, the best compressive strength properties were observed in the composite samples using 10% flax fiber and compatibilizer.

Accurate measurements of delayed neutron data for reactor applications: methodology and application to 235U(nth,f)

Large inconsistencies still exist in nuclear data libraries regarding the kinetic parameters of delayed neutron (DN) precursors. As an example, there is a 17% gap between ENDF-B/VIII.0 and JEFF-3.3 on the average lifetime T1/2 of DN precursors from thermal fission of 235U. This parameter is of major importance for reactivity predictions of nuclear reactors in nominal or accidental configurations. In this context, CEA is actively participating to the ALDEN project (Average number and Lifetime of DElayed Neutrons) which aims at providing the nuclear data community with new data sets of DN from thermal and fast neutron induced fission of various actinides. A dedicated experimental setup was designed and optimized for that purpose and is presented in this paper. It consists of a “long counter” detector containing 16 proportional counters filled with 3He, embedded in a high density polyethylene matrix. The detector surrounds a fissile target prepared in the form of a miniature fission chamber, containing a few hundreds of micro-grams of fissile material. This set-up is connected to fast and efficient neutron shutters that can produce step-irradiations of variable durations. The equations driving the DN counting following step-irradiations of the fissile target are established and discussed in the perspective of DN yield or group parameter measurement. A comprehensive analysis of the different steps of data reduction is detailed: dead time characterization, Region of Interest (ROI) determination, absolute and relative efficiency calibration, fission rate estimation, irradiation time and background determination, DN decay curve production and physical parameter fitting. Following a prototype experiment performed in 2018 at the PF1b cold neutron beam line of Institute Laue Langevin (ILL, Grenoble, France), we discuss here the analysis of two campaigns occurring in 2019 and 2021 in which significant improvements were achieved in terms of background minimization, counting statistics and fission rate determination. The achievements of this work are the measurement of the delayed neutron emission per fission for the thermal neutron induced fission of 235U, estimated at (1.625 ± 0.010) % and the group parameters leading to an estimated lifetime of T1/2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${T}_{1/2}$$\\end{document} = (8.87 ± 0.10) s. Those results are consistent with the values recommended by the IAEA/CRP work and they come with reduced uncertainties compared with previously published results.

Melt blending of commercial linear polyethylene with low-entangled ultra-high molecular weight polyethylene: From dispersion compatibility to viscoelastic scaling laws

This study investigates the dispersion and compatibility of low-entangled “dis-entangled” UHMWPE (dis-UH) in a high-density polyethylene (HDPE) matrix using solvent-free melt-blending conditions and compares it with entangled UHMWPE (eUH) in the same matrix. The findings reveal that dis-UH/HDPE exhibits a significantly lower viscosity ratio than eUH/HDPE (1 and 4, respectively), indicating a lower critical capillary number (Cacritical), thus enhanced dispersion and compatibility. Blends with varying dis-UH content up to 20 wt% show homogeneity, evidenced by DSC and SEM analysis, and demonstrate improved mechanical properties by 36 % in the maximum stress (σmax) and 39 % in Young's modulus (E). Linear viscoelasticity assessments reveal that higher dis-UH content slow the dynamics and increase the apparent weight average molecular weight (Mw), consistent with previous reports for linear entangled PE. The zero-shear viscosity (η0) scaling with Mw (η0∝Mn) is adjusted for high polydispersity, yielding a transitional point in the scaling exponent (n) from 3.6 to 3 at a reptation number of entanglement segments (Mr/Me) of ∼287, in line with theoretical predictions. To rationalize the success of the homogenization process, we propose a qualitative molecular picture inspired from the constraint release Rouse mechanism involved in the disorientation process of bi-disperse linear polymers. In the case of dis-UH/HDPE blends, with initially lower density of long-long entanglements within dis-UH, and the highest density of short-short entanglements within HDPE matrix, the formation of long-short entanglements between dis-UH and HDPE is facilitated, which results in successful homogenization process. In the contrary, the establishment of long-short entanglements in eUH/HDPE blends will require unwinding of the long-long entanglements, which holds a higher kinetic barrier compared to dis-UH/HDPE blends, leading to unsuccessful homogenization.

Probing Viscoelastic Properties and Interfaces in High-Density Polyethylene Vitrimers at the Nanoscale Using Dynamic Mode Atomic Force Microscopy.

Vitrimers are a new class of heterogeneous polymers that combine the best features of thermosets with those of thermoplastics. The introduction of cross-links strongly changes the viscoelastic behavior of vitrimer materials. However, the characterization and understanding of the nanostructures and interfaces in vitrimers resulting from dynamic cross-linking formation remain a major challenge. Here, using dynamic modes of atomic force microscopy (AFM), namely intermodulation AFM (ImAFM) and AFM-based dynamic mechanical analysis (AFM-nDMA), local viscoelastic properties and interfaces at the nanoscale length of high-density polyethylene (HDPE) vitrimer materials are reported. ImAFM imaging in combination with the k-means clustering algorithm clearly reveals two distinct phases in the vitrimer system with highly different viscoelastic properties. AFM-nDMA further provides quantitative nanoviscoelastic properties at the nanoscale to confirm that there is a cross-linking-rich aggregation area forming a nanosize network structure in the cross-linking-poor matrix phase. The cross-linking-rich region shows a similar elastic modulus but much higher adhesion force measured by AFM compared to the cross-linking-poor HDPE matrix. Furthermore, the frequency influence on the local viscoelastic properties of HDPE vitrimer at the nanoscale was initially screened. The observed HDPE vitrimer nanostructures and viscoelastic properties at the nanoscale also provide explanations on the observed bulk HDPE vitrimer crystallinity decrease and dimensional stability increase compared to HDPE. Therefore, probing the viscoelastic properties and interfaces of HDPE vitrimer provides important insights into understanding of the correlations between the vitrimer nanostructure and the bulk mechanical and rheological behaviors.

Optimizing the rheological and mechanical properties of ultra-highly filled wood fiber/polyethylene composites through binary alloy matrix strategy

Enhancing the interfacial adhesion and rheological behavior of ultra-highly filled wood-plastic composites (UH–WPCs) presents a considerable challenge. We developed a bespoke binary alloy matrix of high-density polyethylene (HDPE) and maleated polyethylene (MAPE) to fabricate UH-WPCs with 70–90 wt% filler contents. Fourier-transform infrared spectroscopy and thermogravimetric analysis validated that about 22.3 % of MAPE engaged in esterification with wood fibers (WFs) in 80 wt% loading UH-WPCs, manifesting in noteworthy plasticization as evidenced by WFs' sheet-like structures. Rheological assessments illustrated that higher MAPE proportions reduced the viscosity of both the specialized alloy and UH-WPC melts significantly. By fine-tuning the MAPE to HDPE ratio to 16:2, we achieved marked enhancements in UH-WPCs' mechanical properties and dimensional stability: tensile strength and flexural strength increased by up to 141.7 % and 151.0 %, respectively, while creep strain and equilibrium water absorption decreased by as much as 27.3 % and 36.7 %. This research lays a robust scientific foundation for the efficient processing and enhancement of UH-WPCs, highlighting its potential for substantial improvements in mechanical performance, stability, and processability.

Preparation, characterization, and antistatic applications of high‐density polyethylene/polyaniline blends

AbstractTo obtain electrostatic charge dissipative (ESD) materials, high‐density polyethylene (HDPE) and polyaniline (PANI) blends are synthesized by the solution blending method. To prepare the blends, 0.5, 1.0, and 3.0 wt% of PANI are introduced into the HDPE matrix. The prepared blends are investigated by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), and scanning electron microscope (SEM). Additionally, stress–strain curves are used to examine the blends' mechanical properties. Polyaniline additions indicated an increase in thermal stability by approximately 1°C in the blends but decrease in mechanical properties. The four‐probe technique is used to determine the electrical conductivity of blends, which is found to be between 10−7 and 10−10 S/cm. The results of the conductivity values have indicated that all blends have great potential to be used as antistatic materials. For antistatic applications, the ESD performance of the blends is determined at different corona voltages. Blends achieved the antistatic requirements with a 10% cutoff decay time of approximately 2.0 s and a 1/e time of approximately 1.0 s, demonstrating quick dissipation of static charges. According to antistatic decay times, it has been shown that all blends obtained in this study can be used as antistatic material at 3 kV corona voltage.

Effects of processing temperature, pressure, and fiber volume fraction on mechanical and morphological behaviors of fully-recyclable uni-directional thermoplastic polymer-fiber-reinforced polymers

This work explores a type of composite called thermoplastic polymer-fiber-reinforced polymers (PFRPs), often referred to as self-reinforced composites (SRCs). A representative PFRP was exemplified using unidirectional (UD) ultra-high-molecular-weight polyethylene (UHMWPE) fibers embedded in a high-density polyethylene (HDPE) matrix. The effects of compression molding temperature and pressure on the mechanical and morphological behaviors of the filament-wound PFRPs with various fiber volume fractions (Vf) were experimentally investigated.The results elucidate the evolution of morphologies and tensile properties of the PFRPs due to thermal melting, fiber misalignment from pressure, and Vf-induced structural variance, which has not been comprehensively reported yet. The highest specific tensile strength and modulus of the PFRP laminae reach 600 MPa/(g/cm3) and 31 GPa/(g/cm3), respectively. These properties are comparable to glass-/aramid-fiber-reinforced polymers (GFRPs, GFRTPs, AFRPs, and AFRTPs), with PFRPs exhibiting better ductility (specific strain at peak load ≈ 4%/(g/cm3)) than other common polymer composites.The motivation for this work was the high recyclability of PFRPs, which can be recycled by melting both the fibers and the matrix, and then reshaped them for re-manufacturing composites to maximize the efficiency in material reuse. This process simplifies the implementation of closed-loop recycling, re-manufacturing, and reuse to support sustainability in composites. This work aims to contribute to advancing thermoplastic PFRPs for their potential applications in various industries.

Post-consumer high-density polyethylene matrix reinforced by sugarcane bagasse fibers treated in stearic acid solution

The study aimed to advance composite technology by exploring the potential of recycled materials, specifically high-density polyethylene (HDPE) composites reinforced with sugarcane bagasse fibers. This research not only addresses environmental concerns by utilizing recyclable materials but also aims to offer significant technical, economic, and social advantages. The investigation focused on formulating and evaluating these composites, considering varying proportions of untreated sugarcane bagasse fibers and examining the effects of chemical treatment with stearic acid at different temperatures. Using a conical twin-screw extruder and injector, the researchers produced and analyzed the composites both morphologically and mechanically. The principal findings indicated that the inclusion of untreated fibers improved the stiffness and tensile strength of the composites. Nevertheless, adhesion between the fibers and the matrix was compromised, especially with higher fiber concentrations. Chemical treatment at 40 °C significantly improved fiber/matrix interactions, thereby enhancing the reliability and mechanical properties of the composites. This treatment led to substantial increases in tensile and compressive strengths, particularly noticeable in composites containing 10%–15% fiber by weight. These results not only demonstrate the feasibility of using recycled HDPE and sugarcane bagasse fibers in composite materials but also suggest avenues for further exploration. Future research could delve deeper into optimizing chemical treatment processes to achieve even better adhesion and mechanical performance. Moreover, exploring broader applications in industries such as automotive, aerospace, naval, civil engineering, and packaging could unlock new opportunities for these sustainable composites. This study thus paves the way for advancing composite technology towards more environmentally friendly and economically viable solutions.

Characterization of Posidonia oceanica Fibers High-Density Polyethylene Composites: Reinforcing Potential and Effect of Coupling Agent

This study investigated the influence of fiber loading and maleated polyethylene (MAPE) coupling agent on the structural, thermal, mechanical, morphological properties, and torque rheology of high-density polyethylene (HDPE) reinforced with Posidonia oceanica fiber (POF) composites. HDPE/POF composites, both with and without MAPE, were manufactured using a two-step process: composite pellets extrusion, followed by test samples injection molding with various POF loadings (0, 20, 30, and 40 wt%). HDPE/POF composites reinforced with higher loading of POF (40 wt%) exhibit superior stiffness, better crystallinity, and higher stabilized torque and mechanical energy (Em) compared to other composite formulations. Therefore, varying the POF loading leads to extrusion and injection processing variations. Furthermore, the coupling agent significantly enhances the tensile strength, ductility, impact strength, crystallinity, stabilized torque, and Em of the HDPE/POF composite. This improvement is due to the enhanced interfacial adhesion between the POF and the HDPE matrix with the addition of the MAPE, as supported by the Scanning Electron Microscopy (SEM) micrographs.

Optimization Course of Titanium Nitride Nanofiller Loading in High-Density Polyethylene: Interpretation of Reinforcement Effects and Performance in Material Extrusion 3D Printing.

In this study, titanium nitride (TiN) was selected as an additive to a high-density polyethylene (HDPE) matrix material, and four different nanocomposites were created with TiN loadings of 2.0-8.0 wt. % and a 2 wt. % increase step between them. The mixtures were made, followed by the fabrication of the respective filaments (through a thermomechanical extrusion process) and 3D-printed specimens (using the material extrusion (MEX) technique). The manufactured specimens were subjected to mechanical, thermal, rheological, structural, and morphological testing. Their results were compared with those obtained after conducting the same assessments on unfilled HDPE samples, which were used as the control samples. The mechanical response of the samples improved when correlated with that of the unfilled HDPE. The tensile strength improved by 24.3%, and the flexural strength improved by 26.5% (composite with 6.0 wt. % TiN content). The dimensional deviation and porosity of the samples were assessed with micro-computed tomography and indicated great results for porosity improvement, achieved with 6.0 wt. % TiN content in the composite. TiN has proven to be an effective filler for HDPE polymers, enabling the manufacture of parts with improved mechanical properties and quality.

Effects of incorporating cellulose fibers from Yucca treculeana L. on the thermal characteristics of green composites based on high-density poly-ethylene: An eco-friendly material for cleaner production

This work has developed advanced technical applications in clean production based on a biocomposite high-density polyethylene (HDPE) reinforced cellulosic Yucca treculeana L. fibers (YTFs) from agriculture waste leaves. Once the extraction was complete, the fibers were chemically treated with a low concentration (3% for 4 h) of sodium bicarbonate (NaHCO₃) to remove impurities from their surface and increase their adhesion capacity. Furthermore, this work aimed to understand how adding YTFs (10%, 20%, and 30%) influences the dynamic properties of the polymer-based clean production biocomposites. The impact of the additions on the damping behavior in terms of loss modulus (E″), storage modulus (E′), glass transition temperature (Tg), and loss factor (tanδ) of YTFs/HDPE biocomposites was evaluated at a frequency of 1 Hz using the dynamic mechanical analysis. In particular. According to the results, E′ is significantly improved by adding YTFs. Furthermore, to reach a Tg of about 80 °C, YF30/HDPE offers a tanδ of 0.164, an E′ of 2491 MPa, and an E″ of 223 MPa. Scanning electron microscope images reveal a fiber-polymer interface that adheres firmly to the HDPE matrix. This study highlights the promising potential of YF/HDPE biocomposites as sustainable and cost-effective replacements for conventional materials in diverse applications. Indeed, given its load-bearing capacity and recyclability, this type of biocomposites would be a wise choice for manufacturing automotive interior trim, sporting goods, and eco-friendly building materials. Further research and development could optimize the properties of these biocomposites and extend their use to various cleaner production industries.

Effect of temperature on the uniaxial tensile properties of wood plastic composites: Experimental investigation and numerical analysis

Seven groups of uniaxial tensile experiments on wood plastic composites with a High Density Polyethylene (HDPE) matrix at different temperatures were completed in this paper. The test temperatures ranged from -60 °C to 60 °C, with a temperature difference of 20 °C for each group. All samples exhibited tensile brittle fracture. The test results showed that the tensile strength of the specimens decreased continuously with increasing temperature. Taking 0 °C as the reference temperature, the ultimate strength of the sample at -60 °C was 1.63 times that at 0 °C. When the temperature was 60 °C, this value was 0.41. Then, it can be calculated that the ratio of the strength of the sample at -60 °C to that at 60 °C was approximately 3.93, and the corresponding ratio of the elastic modulus was approximately 4.52. This shows that the mechanical properties of WPC are sensitive to changes in temperature. The variation coefficient of the average strength and elastic modulus of WPC for different specimens at different temperatures was less than 0.17, showing good stability due to the small dispersion of mechanical properties among different samples at any specific temperature.

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.

Shish‐kebab structure evolution of HDPE/UHMWPE during hot drawing

AbstractUsing a solution‐mixing method, this research aimed to fabricate high‐density polyethylene (HDPE)/ultra‐high molecular weight polyethylene (UHMWPE) composite materials with uniform dispersion. By incorporating a small quantity of UHMWPE as a nucleating agent, additional contact points were introduced to enhance the crystallization rate of the HDPE matrix. Thermal stretching experiments were conducted on composite systems with varying UHMWPE contents and molecular weight additions at different temperatures. Elevating the stretching temperature was found to decrease the yield strain and yield strength, extend the stage of tensile plastic deformation, and diminish the overall mechanical properties of the composite material. Notably, stretching at temperatures ranging from 90 to 110°C accentuated the development of internal crystal orientation structures. Under low strain conditions, crystal slip was observed to be concentrated, with single crystals undergoing continuous stretching and breaking, resulting in a decrease in the long period. Conversely, at high strains, the induced formation of oriented lamellar structures was observed.Highlights Prepared HDPE/UHMWPE blends by UHMWPE with varying molecular weights. Analyzed the alterations in the HDPE/UHMWPE blends' internal crystal structure. Influence of UHMWPE addition, temperature on the evolution of crystal structure.

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.

Developing Eco-Friendly 3D-Printing Composite Filament: Utilizing Palm Midrib to Reinforce High-Density Polyethylene Matrix in Design Applications.

Designers actively pursue the use of novel materials and concepts in furniture and interior design. By providing insights into their processing behavior and suitability for 3D-printing processes, this research helps to highlight the potential of using waste materials to create more environmentally friendly and sustainable 3D-printing filaments that can be used in furniture and interior design. Furthermore, the study evaluates the effect of incorporating palm midrib nanoparticles (DPFNPs) to reinforce a high-density polyethylene (HDPE) matrix with different loadings such as 10, 20, 30, 40, and 50 wt.%. The composites were extruded into filaments using a manual extruder, which was then utilized to fabricate 3D-printed specimens using a 3D-printing pen. The effect of adding DPFNPs on the composite's chemical, thermal, and mechanical properties was evaluated, with a particular focus on how these modifications influence the melt flow rate (MFR) and, subsequently, the material's printability. The results revealed that HDPE and filament composites presented similar FTIR spectra. On the other hand, the filament composites presented an increase in the thermal stability and a decrease in the mechanical strength with increasing DPFNP content in the HDPE matrix. The filaments were successfully printed using a 3D-printing pen. Thus, using DPFNPs in the HDPE matrix presents a low-cost alternative for filament production and may expand 3D-printing applications in interior and furniture design with more sustainable materials. Future work will delve into optimizing these composites for improved printability and assessing their recyclability, aiming to broaden their applications in 3D printing and beyond.

Assessment of mechanical and physicochemical properties of palm fiber composites: Effect of alkaline treatment and volume alterations

This study assesses the impact of alkaline treatments and volume fractions on biocomposites composed of a high-density polyethylene (HDPE) matrix reinforced with date palm tree fibers (FPDS). Tensile tests were conducted on both untreated and NaOH-treated biocomposites. Additionally, fiber analysis was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results reveal higher strength and stiffness compared to HDPE, albeit with limited plasticity making the material brittle. The NaOH treatment enhances certain mechanical properties. Further assessments encompassed hardness, density, melt index, and Izod impact tests. Two volume fractions, 20% and 25%, of FPDS were tested. The study establishes a correlation between empirical predictions and artificial neural network (ANN) models. Notably, an ANN architecture consisting of two input factors, 10 hidden nodes, and one output provides the analysis of mechanical properties. This investigation highlights the potential of FPDS-reinforced HDPE biocomposites, emphasizing their mechanical performance under various treatments and fiber levels.

Influence of Strong Shear Field on Structure and Performance of HDPE/PA6 In Situ Microfibril Composites.

As one of the most widely applied general-purpose plastics, high-density polyethylene (HDPE) exhibits good comprehensive performance. However, mechanical strength limits its wider application. In this work, we introduced the engineering plastic PA6 as a dispersed phase to modify the HDPE matrix and applied multiple shears generated by vibration to the polymer melt during the packing stage of injection molding. SEM, 2D-WXRD and 2D-SAXS were used to characterize the morphology and structure of the samples. The results show that under the effect of a strong shear field, the dispersed phase in the composites can form in situ microfibers and numerous high-strength shish-kebab and hybrid shish-kebab structures are formed. Additionally, the distribution of fibers and high-strength oriented structures in the composites expands to the core region with the increase in vibration times. As a result, the tensile strength, tensile modulus and surface hardness of VIM-6 can reach a high level of 66.5 MPa, 981.4 MPa and 72, respectively. Therefore, a high-performance HDPE product is successfully prepared in this study, which is of great importance for expanding the application range of HDPE products.

Assessing the recycling potential of thermosetting polymer waste in high-density polyethylene composites for safety helmet applications

Abstract The rising demand for thermosetting polymers has resulted in the production of large amounts of industrial waste. Environmental issues due to waste landfills and increased raw material costs for new product development have led to the development of innovative recycling methods. This study focuses on the development of a product (helmet shell) by reinforcing thermosetting polymer waste (TPW) as a filler in a high-density polyethylene (HDPE) matrix. The HDPE and TPW were converted into extrudates using a twin-screw extruder. Then, the extrudate was pelletized to use as raw material for the injection molding machine. The HDPE/TPW composites were fabricated using injection molding. Maleic anhydride-grafted polyethylene was employed as a compatibilizer. In the composite, the TPW volume was reinforced at various weight percentages, ranging from 0 to 35 wt%. The mechanical, thermal, and viscoelastic properties of the composites can be enhanced by uniformly dispersing TPW in the HDPE matrix. However, it is difficult to achieve uniform dispersion at higher TPW volumes owing to the agglomeration effect. According to these findings, the mechanical properties were enhanced by up to 30 wt% addition of TPW. The findings suggest that the proposed composite has sufficient mechanical properties to be suitable for the fabrication of helmet shells.