High Density Polyethylene Composites Research Articles

Effect of Agricultural Biomass Residues on the Properties of Recycled Polypropylene/Polyethylene Composites.

The aim of the study was to assess the usefulness of agricultural biomass residues as reinforcement in recycled polymer matrices. In this study, recycled polypropylene and high-density polyethylene composites (rPPPE) filled with three types of biomass residues, sweet clover straws (SCS), buckwheat straws (BS) and rapeseed straws (RS), are presented. The effects of the fiber type and the fibers content on the rheological behavior, mechanical properties (including tensile, flexural and impact strength), thermal stability and moisture absorbance were determined, in addition to morphological analysis. It was revealed that the addition of SCS, BS or RS increased the materials' stiffness and strength. The reinforcement effect increased as the loading of the fibers was increased, especially for BS composites in the flexural test. After the moisture absorbance test, it was found that the reinforcement effect slightly increased for the composites with 10% fibers but decreases with 40% fibers. The results highlight that the selected fibers are a feasible reinforcement for recycled polyolefin blend matrices.

Morphology and physical properties of composites based on high-density polyethylene/propylene-ethylene random copolymers blends and carbon black

High-density polyethylene (HDPE) composites containing propylene-ethylene random copolymers (PEC) elastomer and carbon black (CB) were prepared by melt blending in an effort to obtain excellent balance of properties. HDPE matrix and PEC elastomer were immiscible, and CB fillers were selectively located in HDPE matrix. The introduction of CB fillers into the HDPE/PEC blend significantly improved the viscoelasticity of the composite melts. Percolation network of CB particles was formed at CB content of 5 wt%, which consequently largely improved the conductivity of composites, and the surface resistance decreased to 106 Ω (square)−1, equal to the antistatic range. DSC results suggested that CB with a content more than 5 wt% showed nucleation effect, improving the degree of crystallinity of HDPE. Moreover, the incorporation of CB improved stiffness of composites, and decreased ductility compare with HDPE/PEC blend. The combination of adjustable conductivity and mechanical properties, as well as improved melt viscoelasticity wold further broaden the application fields of HDPE based composites.

Remarkable effects of silicone rubber on flame retardant property and mechanical properties of crosslinked high‐density polyethylene/bio‐based magnesium phosphate flame retardant (MHPA) composite

AbstractIn this paper, a new bio‐based flame retardant MHPA was prepared by the reaction of magnesium hydroxide (MH) and phytic acid (PA). Then the crosslinked high‐density polyethylene (HDPE) flame‐retardant composite was prepared by adding it and silicone rubber (SR) into HDPE and using electron beam irradiation. The test results of limiting oxygen index (LOI) and cone calorimeter test (CCT) show that the combination of MHPA and SR can increase the flame retardancy and smoke suppression performance of HDPE. The LOI of HDPE composite with 10 parts of SR is 28.3%, and its pHRR, THR and TSP values are reduced to 454.1 kW/m2, 99.7 MJ/m2 and 8.3 m2, respectively, which is because MHPA and SR jointly promote the formation of continuous and high‐density carbon slag in the combustion process of HDPE and inhibit the penetration of flame. In addition, the HDPE composite with 10 parts of SR has significant tensile strength, elongation breaking strength and tear strength, because SR can produce continuous stable structure with HDPE after irradiation and crosslinking. Therefore, this study verified that MHPA and SR together can effectively improve the flame retardancy, smoke suppression and mechanical properties of HDPE composite.

Development of bio‐based magnesium phosphate flame retardant for simultaneously improved flame retardancy, smoke suppression and mechanical properties of HDPE

AbstractIn this article, MHPA, a novel bio‐based flame retardant, was prepared by a reaction of magnesium hydroxide (MH) and phytic acid (PA). Then, MHPA was added into high‐density polyethylene (HDPE) to prepare flame‐retardant HDPE composite. This work aims to add MHPA into HDPE to flame‐retardant HDPE composites by melt blending to significantly reduce the smoke and toxic gases produced during combustion. The limiting oxygen index (LOI) and cone calorimeter test (CCT) results show that the flame retardancy and smoke suppression of HDPE can be improved by the mixture of MHPA and MH. The LOI of HDPE/MHPA/MH was 26.3%, and its peak heat release rate (pHRR), total heat release (THR) and total smoke production (TSP) values decreased by 38.6%, 27.3%, and 65.2%, respectively, compared with pure HDPE. In addition, HDPE/MHPA/MH composites have significant tensile strength, elongation breaking strength, and tear strength because of the interface compatibility of bio‐based MHPA. Therefore, this study verified that the flame retardancy, smoke suppression, and mechanical properties of HDPE composites could be effectively improved when MHPA and MH are added to HDPE simultaneously.

Low cost and easily scalable microwave absorbing material based on three-layer honeycomb sandwich structures

The present work describes a new three-layer structure for developing lightweight and low-cost microwave absorbing material using available honeycomb (HC) structures sandwiched by high density polyethylene (HDPE) composites loaded with a 3% of hybrid mixture of carbon black (CB) and graphite (GF) as dielectric filler (HDPE/HB) or 5% of granitic quarry waste (HDPE/GQW) as magnetic material. The microwave absorbing properties was studied in the X-band frequency range, which is useful for military purpose. Uncoated HC structure presented reasonable microwave absorbing properties, which could be improved by a proper choice of the thickness and cell size. The three-layer structure constituted by HC (4 mm thick) sandwiched by HDPE composites (1 mm thick) with HDPE/GQW composite as the matching layer resulted in minimum reflection loss of − 30.0 dB, which corresponds to electromagnetic wave attenuation higher than 99.9%. The present work illustrates the possibility of developing low cost and lightweight microwave absorbing material with easy and scalable fabrication procedures, for applications in both civil and military fields. The results also provide useful application of the waste generated from crushed gneiss rock during the production of fine aggregates, which is important for the environmental sustainability purpose.

Gamma-ray attenuation parameters of HDPE filled with different nano-size and Bulk WO3

High-density polyethylene (HDPE) was obtained through a compression molding technique, and incorporated with different filler weight fractions (0, 10, 15, 25, and 35%) of bulk WO3, and two different WO3 nanoparticle sizes (45 nm and 24 nm). The radiation attenuation ability of the new category of polymer composite HDPE/WO3 was evaluated using gamma-ray energies ranging from 59.53 up to 1332.5keV of four radioactive sources 241Am, 133Ba, 137Cs, and 60Co. The mass attenuation coefficients μm, the total molecular cross-section σmol, the effective atomic cross-section σatom, the total electronic cross-section σel, the effective atomic number Zeff, electron density Neff, the half value layer (HVL), the tenth value layer (TVL), and the relaxation length were investigated. The obtained results of the gamma-ray attenuation parameters exhibited an outstanding influence of the size and weight fraction of WO3 filler on the gamma-ray shielding ability of the HDPE composite. A significant improvement was detected at low gamma-ray energies. The HVL of the synthesized HDPE composites is compared with that of pure lead as a conventional shielding material. HDPE composite filled with the smaller size of WO3 nanoparticle shows good improvement in the attenuation parameters, which suggests promising applications in radiation protection and gamma-ray shielding.

Strengthening effect of phosphate sludge by-product and styrene-butadiene rubber on the properties of high-density polyethylene composites

Strengthening effect of phosphate sludge by-product and styrene-butadiene rubber on the properties of high-density polyethylene composites

Comparative Evaluation of the Stiffness of Abaca-Fiber-Reinforced Bio-Polyethylene and High Density Polyethylene Composites

The use of bio-based matrices together with natural fibers as reinforcement is a strategy for obtaining materials with competitive mechanical properties, costs, and environmental impacts. However, bio-based matrices, unknown by the industry, can be a market entry barrier. The use of bio-polyethylene, which has properties similar to polyethylene, can overcome that barrier. In this study, composites reinforced with abaca fibers used as reinforcement for bio-polyethylene and high density polyethylene are prepared and tensile tested. A micromechanics analysis is deployed to measure the contributions of the matrices and reinforcements and to measure the evolution of these contributions regarding AF content and matrix nature. The results show that the mechanical properties of the composites with bio-polyethylene as a matrix were slightly higher than those of the composites with polyethylene as a matrix. It was also found that the contribution of the fibers to the Young's moduli of the composites was susceptible to the percentage of reinforcement and the nature of the matrices. The results show that it is possible to obtain fully bio-based composites with mechanical properties similar to those of partially bio-based polyolefin or even some forms of glass fiber-reinforced polyolefin.

Analysis of Recycled HDPE Composite with OPEFB-Based Cellulose Fiber Reinforcement Characteristics for Casing Electronic Materials

Composite is a product of advanced material innovation which has better mechanical properties than a single material. In addition, composites also have high impact strength so they can be applied as cassing electronic, construction of boat walls, car dashboards, and others. This innovative product can be made from high density polyethylene (HDPE) thermoplastic waste material with cellulose filler based empty palm oil fruit bunches (OPEFB). In this study, a comparison of composite modifications between HDPE and cellulose fibers was carried out. The ratio of matrix and filler composition used in this study is 90:10. The mixing of HDPE : Cellulose fibers using injection melt blending system and extruder technique. The composites are then made into specimens for tensile strenght and impact tests. The results of the tensile strenght and impact test HDPE : Cellulose fiber composite with ratio 90:10 is 27.000 Mpa and 0.261750877 Joules. Analysis results Scanning Electron Microscopy (SEM) on the morphology of the composite fracture, it is known that there is a bond between the matrix (HDPE) and filler (cellulose fiber). The results of this study indicate that composite of HDPE: cellulose fiber based OPEFB (90:10) has potential as a material for cassing electronic.

Grafting of poly(stearyl acrylate) on cellulose fibers as 3D-printable HDPE composites

This paper aimed to produce a bio-based filament, suitable for 3D printing (fused deposition modeling), made of surface modified cellulose fiber and high density polyethylene. The cellulose fibers (CF) were first surface modified and transformed into a CF-based macroinitiator through an esterification reaction with the 2-bromoisobutyric acid. We finally studied the ability of this CF-based macroinitiator to initiate a single electron transfer-living radical polymerization (SET-LRP) with an hydrophobic monomer: the stearyl acrylate. The grafting of poly(stearly acrylate) onto the cellulose fibers did strongly increased the adhesion, compatibility of the modified fibers with the hydrophobic host matrix (HDPE). Finally, the resulting hydrophobic fibers were extruded with the high density polyethylene (HDPE) through a counter-rotating twin-screw extruder, yielding a bio-based filament suitable for FDM 3d printing. The successful surface modification, such as the correct incorporation of the modified fibers into the thermoplastic matrix, were characterized through ATR-FTIR, 13C CP-MAS NMR, FE-SEM, and mechanical testing. Throughout those characterization techniques, it was concluded that the fiber surface modification significantly improved the compatibility of the fibers with HDPE. Finally, the 3D printing properties of the composite were tested and compared to those of pure HDPE through the 3d printing of simple objects. It was concluded that the printability of the composite made with poly(stearyl acrylate)-grafted cellulose overcomes the problem (shrinkage, warpage, print fidelity) encountered with the printing of pure HDPE.Graphical abstract

Thermal and Acoustic Performance of Green Polyethylene/Cork Composite for Civil Construction Applications

In this study, green high-density polyethylene (GHDPE) composites with 5, 10 and 15% natural powdered cork (CP) with and without 5% maleic anhydride (PE-g-MA) were developed in order to evaluate the potential of these materials for civil construction applications. The composites were produced in a co-rotating twin-screw extruder and injection molded. An impedance tube was used to determine the acoustic behavior of the composites, which were then used as ceiling tiles in prototypes of provisional constructions in order to study ascertain their performance with respect to thermal comfort in the City of Teresina, PI - Brazil. Our data indicates that composites sound absorption coefficient values are good between 500 and 1200 Hz, especially for those with a higher percentage of cork, with the lowest absorption rate observed for composites containing PE-g-MA. The composites used in the prototypes provided a decrease in the internal temperature of the built structure.

Microstructural Characterization and Property of Carbon Fiber Reinforced High-Density Polyethylene Composites Fabricated by Fused Deposition Modeling.

As a promising industrial thermoplastic polymer material, high-density polyethylene (HDPE) possesses distinct properties of ease to process, good biocompatibility, high recyclability, etc. and has been widely used to make packaging, prostheses and implants, and liquid-permeable membranes. Traditional manufacturing processes for HDPE, including injection molding, thermoforming, and rotational molding, require molds or post processing. In addition, part shapes are highly restricted., Thus, fused deposition modeling (FDM) is introduced to process HDPE materials to take advantage of FDM's free of design, no mold requirement, ease and low cost of processing. To improve the mechanical properties (such as stiffness and strength) and thermal resistance of HDPE, carbon fiber (CF) was incorporated into HDPE, and CF-reinforced HDPE composites were successfully fabricated using FDM process. In addition, the effects of CF content on surface quality, microstructure characterizations, tensile properties, dynamic mechanical properties, and thermal properties have been investigated. Experimental results show that an appropriate CF content addition is beneficial for improving surface quality, and mechanical and thermal properties.

AFM Measurements and Testing Properties of HDPE and PBT Composites with Fillers in the Form of Montmorillonite and Aluminum Hydroxide.

This paper presents the effect of the addition of fillers such as aluminum hydroxide or montmorillonite on the structure and properties of polymers such as high-density polyethylene (HDPE) and polybutylene terephthalate (PBT). Both types of specimens were obtained by injection molding. X-ray diffraction examinations were performed on the materials obtained to determine the effect of the addition of the fillers used on the degree of crystallinity of the composites. The density and hardness of the composites were evaluated, and the static tensile test and the analysis of the structure parameters using atomic force microscopy (AFM) were also carried out. It was shown that the addition of powder fillers to polymers such as high-density polyethylene and polybutylene terephthalate affects the structure parameters such as surface roughness, mean grain size, anisotropy ratio, fractal dimension, the corner frequency of the composites, and mechanical properties such as Young's pseudo-modulus, average adhesion force, hardness, and tensile strength.

Evaluation of crystallinity, thermal, mechanical and morphological features of high density polyethylene composites reinforced with crosslinked semifluorinated acrylate polymer microspheres

This study mainly aims both to prepare well-shaped crosslinked 3,3,4,4,5,5,6,6,7,7,8,8,8 tridecafluorooctyl-4-(acrloyloxy) benzoate (ABCF13) polymer microspheres and to investigate the influences of the prepared microspheres addition on the crystallinity, thermal, mechanical and morphological features of high density polyethylene (HDPE). The suspension polymerization method was used for the production of well-defined microspheres and, the content of the microspheres varied from 1.0% to 10.0% in the composites. The characterization of crosslinked poly(ABCF13) microsphere-loaded HDPE composites were performed via powder X-ray diffraction, differential scanning calorimeter, universal mechanical (tensile and impact) testers and scanning electron microscope (SEM) techniques. According to the experimental findings, a and b unit cell parameters increased initially and reached maxima with the sample including 5.0% microsphere, which were followed by dramatic decreases, while c parameter remained relatively unchanged. Thermal analysis also showed that the melting temperature of HDPE reduced with the initial loading of the microspheres, then stayed at a plateau value of about 129°C due to the formation of lattice distortions, generation of microstructural disorders and the defects in the crystal structures. The mechanical test results revealed that there existed considerable improvements in tensile strength, modulus and impact strength. The maximum tensile strength 25.66 MPa, elastic modulus 499.30 MPa and maximum absorbed energy in the impact test 26.84 kJ/m2 (29%, 42% and 41% improvement, respectively) were achieved with the blend involving 5.0% microsphere. After the maxima, the mechanical characters depicted weakening trend as the microsphere content increased in the matrix. The SEM analyses revealed that although there existed fibrillar formations in all samples, the extensions decreased with the increase of the microsphere content. While ductile behavior was observed with the formation of long-bulky extensions at low contents, brittleness started to prevail at high contents with some short and thin fibrils.

Research on Microstructure and Mechanical Properties of Nylon6/Basalt Fiber/High-Density Polyethylene Composites.

As a representative polyolefin, high-density polyethylene (HDPE) has become one of the most commonly used commercial plastics with a wide range of applications in the world. However, its applications are limited due to poor mechanical properties. Hence, it is indispensable to develop composites with improved mechanical properties to overcome this disadvantage. In our work, basalt fiber (BF) and polyamide 6 (PA6)-reinforced HDPE composites were prepared. The effects of adding fiber, organic filler, and polar component maleic anhydride (MAH) on the microstructural characteristics of composites were investigated. Microstructural characterization evidenced that the binary-dispersed phase (PA6/BF) possesses a core-shell structure in which the component PA6 encapsulates the component BF, and the extent of encapsulation declines with the increase of MAH addition. It has been confirmed by scanning electron microscopy (SEM) observation that the microstructure is related to the interfacial tension of components. The effects of multicomponents on the crystallization behavior of composites were studied. The differential scanning calorimeter (DSC) analysis exhibited a significant change in the HDPE microstructure. Results showed that, as nucleating agents, PA6 and BF improve the crystallization rate in the cooling process. Furthermore, the rheological behavior of multicomponent composites was studied. With the increase of MAH, a clear improvement of complex viscosity and storage modulus was observed, of which the mechanism has been discussed in detail. The relationship between microstructure and heat resistance of composites was studied by a thermal deformation test under static fore. It is confirmed that the thermally conductive fiber BF and other components can form a thermally conductive network and channels, thus improving the heat resistance. It can become a composite material, which is suitable for special environments.

Investigation of Mechanical Properties of Coffee Husk-HDPE-ABS Polymer Composite Using Injection-Molding Method

Waste biomass-based natural fibers are being extensively researched nowadays as a composite material with various waste-based high-density polyethylene (HDPE) to utilize the waste biomass and recycle the plastic waste in an effective approach. In this study, chemically modified spent coffee husk (CH) has been applied with different ratios of HDPE to produce composite material and characterized comprehensively to determine the mechanical stability of the products. The injection molding method was used for composite development containing HDPE with untreated and 10 wt% NaOH-treated CH weight ratios of 0%, 15%, 20%, and 25% together with 10 wt% coupling agent and filler materials of acrylonitrile butadiene styrene (ABS) and kaolin clay, respectively. Physicochemical characteristics of untreated CH, 10 wt% NaOH treated CH, pristine HDPE and HDPE-CH composites have been analyzed comprehensively in this study. Adding 25 wt% fiber with 65 wt% HDPE and 10 wt% of ABS (7 wt%)-kaolin clay (3 wt%) increased the tensile and bending properties significantly. This composite presented the maximum tensile, flexural, and impact strengths, which were 36 MPa, 7.5 MPa, and 2.8 KJ/m2, respectively. The tensile strength and bending strength of NaOH-treated coffee husk fibers (CHF) were enhanced by 32% and 29%, respectively. The microstructural characteristics of HDPE with treated and untreated CHF composites analyzed by scanning electron microscopy (SEM) demonstrated the fibers’ and matrix’s excellent adhesion and compatibility. Thus, HDPE polymer-treated CH composite presented excellent stability, which can be expected as a new addition for construction, food packaging, and other industrial applications.

Synthesis and characterization of recycled HDPE polymer composite reinforced with nano-alumina particles

Recycling of High-density Polyethylene (HDPE) plastic is a viable and economical method to progress in the path of a sustainable and eco-friendly initiative towards the eco-sustainable environment. This work is a pilot study to synthesize a polymer nanocomposite material from recycled HDPE reinforced with aluminium oxide nanoparticles to assess its potential applications as a packaging material. The microstructure of the newly synthesized material is characterized using scanning electron microscopy (SEM) analysis, and energy dispersive X-ray spectroscopy (EDS) analysis. X-ray diffraction (XRD) analysis was done to determine the crystallographic structure, while the thermal behaviour was analyzed through Thermogravimetric analysis (TGA) and differential Scanning Calorimetry (DSC) test. Recycled HDPE is already being used in a variety of applications, however, reinforcing with nano alumina particles will alter the properties of HDPE composite which opens up a new arena of possibilities in the field of electronic packaging.

A Study on the Susceptibility of PLA Biocomposites to Drilling

Wood–plastic composites (WPCs) increase the range of applications of materials by creating new material solutions. As part of this research, PLA (polylactic acid)- and HDPE (high-density polyethylene)-based composites were manufactured. Softwood sawdust or conifer bark with different sizes (large and small) were used as filler. In selected cases, the addition of 3% additives, such as calcium oxide in the case of PLA or polyethylene-graft-maleic anhydride in the case of HDPE, were tested. The manufactured composites were examined for their density profile and their susceptibility to drilling, defined by the value of the axial force occurring during drilling. The obtained results revealed that the type of matrix had the greatest influence on the axial forces during drilling. Regardless of the composite formulation, composites based on PLA had 25% to 56% higher axial forces during drilling than those based on HDPE. Furthermore, increasing the proportion of lignocellulosic fillers resulted in a decrease in the value of axial forces during drilling, with PLA composites experiencing a greater decrease than HDPE composites. The type and size of the filler had a minor impact on the axial force values during drilling. The statistical analysis indicated that the additives had a greater influence on HDPE than on PLA.

Fabrication of silver ions aramid fibers and polyethylene composites with excellent antibacterial and mechanical properties

Abstract Nowadays, with the continuous understanding of the pathogenic mechanism of bacterium, the demand for antibacterial plastic products had significantly increased. Besides that, many counties issued mandatory standards for plastic products, which imposed strict requirements on ash content to prevent the addition of excessive inorganic matter to plastics in order to avoid weakening the properties of plastics and deteriorating the recyclable property. Based on this, the development of composites with organic fiber-loaded antibacterial agents is of practicable value and urgency. We used an open-ring addition reaction to modified aramid fiber (AF) by utilizing epoxypropyltrimethoxysilane to react with the reactive groups on the surface of AFs. Subsequently, the modified fibers were surface loaded with silver ionic glass beads. After that, a series of high-density polyethylene composites with excellent mechanical properties and antibacterial properties were prepared using melt mixing method. It was shown that the composite had a low ash value (1.88 wt%) even at a higher filling concentration (7 wt%) and the fibers could change the crystalline properties and morphology of the composite. Because of the fiber reinforcement and crystallization induction effects, the tensile strength and elasticity module of the composites could be improved by 141% and 136%, respectively. In addition, the composites had excellent long-lasting contact antibacterial effects against the inhibition of E. coli. The proposed organic fiber loading technique and antibacterial composites will provide a method for designing and preparing eco-friendly and high-performance plastic products.

The Use of Glasswort (Salicornia europaea) in High Density Polyethylene Composites

ABSTRACT In pursuit of new biobased materials for a sustainable world, glasswort (Salicornia europaea) was utilized in this study as a natural fiber to develop a biocomposite material. Glasswort (GW) reinforced high-density polyethylene (HDPE) composites at different GW percentages were prepared with a high-speed thermo-kinetic mixer. The effect of GW on HDPE composites was thoroughly investigated with Fourier transform infrared (FTIR) spectroscopy, tensile and flexural tests, dynamic mechanical analysis, water contact angle measurements, and scanning electron microscopy (SEM). A new method was also developed by seawater immersion of samples to conduct microbiological analysis. The method included bacteria population count with respect to time. Biointegration was reported to increase as 25% for 20 wt% GW-filled HDPE. The tensile modulus of HDPE increased up to 20% with GW inclusion. The unique properties of this novel composite material proved that GW can be a promising natural fiber for polymer composites.