Properties Of High Density Polyethylene Research Articles

Mechanical, dynamic and tribological characterization of HDPE/peanut shell composites

Polymer composites reinforced with natural fibres are more appealing than conventional materials due to their accessibility, renewability, low weight and price, low density, and biodegradability. There are a wide variety of different natural fibres, such as nutshells, flax, and palm, which can be applied as reinforcements or fillers, showing potential as replacements for inorganic fibres. Plastics are often somewhat economical when producing complex shapes, and the possibility of obtaining composite materials with reduced demoulding times, as no chemical reaction is required, makes them very interesting from an industrial point of view. Moreover, polymers are increasingly used for tribologically stressed components, whereby plastic components replace metallic bearings, gear wheels, or sliding elements. In this regard, this work's objective was to produce composites of high-density polyethylene (HDPE) with different proportions (2, 4, 6, 8. and 10 wt%) of peanut shell (PS) filler and evaluate the influence on the dynamic mechanical and tribological properties of the addition of different amounts of filler. The strain (%) increases with fibre contents of 2 and 4 wt%, but at higher fibre contents, a considerable reduction, approximately 4 times for a fibre content of 6 wt% and an even more substantial reduction for fibre contents of 8 wt% and 10 wt%, could be observed. From the Dynamic Mechanical Analysis (DMA) tests, it could be observed that E' is practically constant for composites for all fibre contents between −20 °C and ~50 °C at 1.5 Hz and 10 Hz, which is ~6 times higher than that of neat HDPE under the same conditions. The tribological assays were carried out by the reciprocating sliding wear test with loads of 10, 20, and 30 N. Although the wear rate (k) and wear volume (V) increased with increasing applied load, these values were similar for fibres with different wt% contents. Thus, the addition of fibre does not modify the tribological properties of HDPE. By Raman spectrum analysis, similar intensities and positions of the bands of the HDPE vibrational mode before and after wear tests could be observed.

Effects of Al2O3 and BaO nano-additives on mechanical characteristics of high-density polyethylene

Fabrication of polymer doped with metal oxides has been recently aimed to improve the physical, chemical, structural, morphological, thermal and mechanical characteristics. Therefore, the current study is directed to dope two nano-metal oxides into high density polyethylene (HDPE) using the roll-mixing and thermal-pressing techniques. The weight fractions of nanofillers were varied from 2.0% to 8.0% in the resulting composite. The FT-IR along with XRD and SEM were used to examine the structural properties of the new nanocomposites. Images from the scanning-electron microscopy demonstrated that Al2O3 and BaO nanoparticles were properly dispersed in the HDPE's polymeric material without essential aggregations. TGA as well as DSC were used to test the effects of Al2O3-NPs and BaO-NPs incorporation on the thermal properties of HDPE. Tensile tests were carried out to detect how the mechanical behavior of the polymeric matrix was affected by the weight fraction of the nanofiller. Elastic modulus, tensile strain (extension) at yield (%), tensile stress at break, ultimate tensile strength, tensile strain (extension) at break (%), and yield stress were determined in this research. It was concluded that the elastic modulus was found to increase with increasing the nanofiller content up to 4.0 wt% for BaO-NPs and 6.0 wt% for Al2O3-NPs to reach 229% and 208% increment, respectively with respect to the hosting matrix. The values of tensile stress at break, yield stress, tensile strain (extension) at break and tensile strain (extension) at yield of the synthesized nanocomposites decreased, as the content of both fillers increased from 2.0 to 8.0 wt%. Finally, a comparison between BaO-NPs and Al2O3-NPs, when added to the HDPE matrix, showed that the BaO nanofiller led to distinct improvements in the mechanical parameters of HDPE than Al2O3-NPs, for the same weight percentage.

Structural and optical properties of HDPE implanted with medium fluences silver ions

The implantation of high-density polyethylene (HDPE) has been conducted using Ag+ ions with energy of 60 keV, achieved fluences 1.5 and 10?1015 ions/cm2. Transmission electron microscopy (STEM) and field emission gun - scanning electron microscopy (FEG-SEM) showed the existence of nanoparticle clusters. X ray photoelectron spectroscopy (XPS) revealed the presence of silver in the sample surface region. The surface topography was studied by atomic force microscopy (AFM), while the surface composition uniformity was analyzed using phase imaging AFM. Optical characterization obtained by spectroscopic ellipsometry (SE) showed changes in refractive index, extinction coefficient and the optical band gap with the fluence of implanted ions.

Investigation on mechanical properties of sugarcane bagasse ash reinforced with incorporation of HDPE - montmorillonite composite materials

Natural Composite are the materials that have more variety of real time product usages and also many industries realize the benefits of these materials, as it offers for light-weight composite structures. The nano-composites are also the composite materials, in which the nano particles have been reinforced into a base matrix material. The result of inclusion of nano particles will have considerable improvements in the mechanical properties, like higher tensile strength, better toughness, higher hardness, etc. In this research, High-Density Polyethylene (HDPE) has been used as matrix material and nano-clay Cloisite-30B as the reinforcement material with sugarcane bagasse ash. A compatibilizer, HDPE grafted with Maleic anhydride (HDPE-g-MA) has also been used to provide a better blending of polymers that will increase their stability and better interaction between the high density polyethylene and nano-clay and montmorillonite minerals with sugarcane bagasse ash. Sample specimen of nano-composite materials had prepared by at different zone temperatures. Also the distribution of these particles such as nano clay, montmorillonite minerals and Sugarcane bagasse ash are in the range of (0-4 wt%) with HDPE in equal proportion. Various mechanical tests like flexural, tensile, hardness and impact using respective dies as per ASTM standard were prepared. In prior to the samples were tested, the investigation of four different wt. % of nano-clay-montmorillonite minerals on the mechanical properties of HDPE had examined to verify the most effective wt % of nano-clay-montmorillonite minerals for improving the strength of nano-composites. The experimental results on mechanical properties of HDPE/Cloisite-30B nano-clay montmorillonite and sugarcane bagasse ash has been analyzed and improvement of strength of materials have also been studied with various wt% (0 to 4%) of nano-clay-montmorillonite and experimental results proved that the sugarcane bagasse ash on HDPE nano-montmorillonite mineral composite yield better strength and desirable mechanical properties.

High-density polyethylene/asphaltene composites: Thermal, mechanical and morphological properties

In this work, a series of high-density polyethylene (HDPE)/asphaltene composites were fabricated via the melt blending method. The composites were characterized, and the degradability, thermal, and mechanical stabilities of the products were analyzed. TGA results showed that HDPE/asphaltene composites had better thermal properties, e.g. higher degradation temperatures than asphaltene-free pristine HDPE. The high intermolecular interactions between the asphaltene and HDPE resulted in the degradation mechanism break, delaying the decomposition of composites and increasing their thermal stabilities. The results of DSC analysis indicated that the presence of asphaltene induces higher crystallinity and melting temperature in the composite matrix. According to the XRD results, the crystalline size was increased by increasing the asphaltene loading level due to the nucleating effect of asphaltene and the proper interactions developed between the asphaltene particles and HDPE chains. The proper dispersion of asphaltene in the composite matrix was confirmed by SEM images. The obtained results from the hardness analysis indicated higher mechanical stability for the composites, proportional to the content of the incorporated asphaltene to the composite. The results showed that asphaltene can be considered as an appropriate choice to improve the HDPE properties.

Tribological properties of High Density Polyethylene based composite: The effect of mollusc shell particles under dry condition

This article highlights the importance of the addition of Mollusc shell (MS) particles, as bio-filler, on the tribological behavior of high-density polyethylene (HDPE) matrix. The elaborated biocomposites are intended to be used as an orthopedic replacement biomaterial. Different mass content of MS (0, 5, 10, 15 and 20 wt. %) have been added to the HDPE matrix. FTIR analysis, crystallinity rate and Rockwell hardness of different bio-composites were performed. A reciprocating pin-on-disc tribometer was used to fulfil dry wear tests. FTIR analysis showed that the presence of MS particles improved the crystallinity of the HDPE phase. Adding to that, it was found that MS improved the hardness, friction coefficient and wear resistance of the HDPE polymer. In fact, by adding 5 wt. % of MS to the HDPE, good tribological properties were achieved. Scanning Electron Microscopy (SEM) was performed to investigate the wear morphology of biocomposites under dry condition. SEM images showed that the morphology of the worn surfaces had been improved by the addition of MS to the polymer. Finally, a wear scenario was proposed.

Effect of Technical Carbon the Deformation-Strength Properties of Low Pressure Polyethylene

The influence of carbon black on the deformation-strength properties of high density polyethylene is considered. It was found that the deformation-strength properties of the polymer matrix change over the entire range of the filler content. The amount of carbon black that can be introduced into high-density polyethylene and obtained a composite material with the optimal combination of stiffness, strength and ductility is established. It was shown that the change in the deformation-strength properties of composites is due to the behavior and influence of carbon black particles on the structure of the polymer matrix.

Tensile Behavior of High-Density Polyethylene Including the Effects of Processing Technique, Thickness, Temperature, and Strain Rate.

The primary goal of this study was to investigate the monotonic tensile behavior of high-density polyethylene (HDPE) in its virgin, regrind, and laminated forms. HDPE is the most commonly used polymer in many industries. A variety of tensile tests were performed using plate-type specimens made of rectangular plaques. Several factors can affect the tensile behavior such as thickness, processing technique, temperature, and strain rate. Testing temperatures were chosen at −40, 23 (room temperature, RT), 53, and 82 °C to investigate temperature effect. Tensile properties, including elastic modulus, yield strength, and ultimate tensile strength, were obtained for all conditions. Tensile properties significantly reduced by increasing temperature while elastic modulus and ultimate tensile strength linearly increased at higher strain rates. A significant effect of thickness on tensile properties was observed for injection molding specimens at 23 °C, but no thickness effect was observed for compression molded specimens at either 23 or 82 °C. The aforementioned effects and discussion of their influence on tensile properties are presented in this paper. Polynomial relations for tensile properties, including elastic modulus, yield strength, and ultimate tensile strength, were developed as functions of temperature and strain rate. Such relations can be used to estimate tensile properties of HDPE as a function of temperature and/or strain rate for application in designing parts with this material.

Thermal and Mechanical Properties of HDPE Reinforced with Al2O3 Nanoparticles Processed by Thermokinectic Mixer

Polymer nanocomposites are a promising area of research due to quite superior to the conventional composites. However, obtaining a homogeneous distribution of the nanoparticles in the matrix has been a great challenge. Standard processing techniques of nanocomposites are non-practical, requiring longer periods and can affect both mechanical and thermal properties of the final product. The thermokinectic mixer is an interesting alternative due to its high-speed rotation leading to a better dispersion of the nanoparticle without compromising the polymer properties. This paper reports for the first time a nanocomposite of high-density polyethylene (HDPE)/Al2O3 processed by the thermokinetic mixer. The addition of Al2O3 nanoparticle (0 to 4% wt) to the HDPE led to an increase in both the melting and crystallization temperature. It was also observed an improvement of the mechanical properties due to the increase in the crystallinity degree, which is a consequence of the multiple nucleation sites of Al2O3 nanoparticles. An optimal composition was obtained at 4% wt of Al2O3. Thus, the nanocomposites processed by the thermokinetic mixer demonstrated a significant enhancement of the mechanical and thermal properties.

Role of percent grafting and chain length of fully fluorinated pendant units in the grafted acrylic compound on crucial characteristic properties of high density polyethylene

This comprehensive study paves way to investigate the effects of not only the extent of grafting but also the chain length of the perfluorinated pendant tail presenting in the three different fluoroalkyl acrylate monomers on the significant characteristic properties; namely the thermal behavior, crystal structure quality, mechanical performance and morphological structure of high density polyethylene (HDPE). The individual graft copolymerizations of the monomer onto HDPE were conducted at the content level from 5 % to 30 % via bulk-melt polymerization. The characterizations of copolymers were performed with differential scanning calorimeter (DSC), powder X-ray diffractometer, universal testing machine and scanning electron microscope (SEM) techniques. As for the results deduced from DSC analysis, both the melting temperatures of HDPE and degree of crystallinity were found to increase systematically with the enhancement in the percent grafting level up to 10 % beyond which the parameters were noted to decrease drastically and reach towards globally minimum values. According to the XRD results, as the percentage of grafting enhanced, the remarkable expansions were observed in unit cell parameters of HDPE crystallized in the orthorhombic symmetry. Moreover, the presence of relatively higher amount of -CF2 groups in the perfluorinated pendant tail caused the formation of three-dimensional lateral repulsions due to its helix structure. Furthermore, there seemed to remarkably improve in the mechanical performance features in case of percent grafting level of 70.6 % where the tensile strength, Modulus and impact strength parameters were measured to be about 42.51 MPa, 539.90 MPa and 41.11 kj/m2, respectively. These reinforcements were found to be explained by the improvement in the regulation, orientations, alignments of HDPE chains. Furthermore, the formation of thick, bulky and long-fibrils were observed at high percent grafting.

Co‐Monomer Type Influence on the Physical and Optical Properties of High Density Polyethylene Synthesized by Chrome Catalyst

AbstractHigh‐density polyethylene (HDPE) with similar density and Melt Index (MI) is synthesized by using a chrome‐based catalyst with different co‐monomers, 1‐hexene (HDPE‐H) and 1‐butene (HDPE‐B). Both samples have a density of 0.955 g cm−3 and MI of 0.1 g per 10 min. The same density and MI have been chosen to minimize the variable that can affect the test result. Different co‐monomers will generate different short‐chain branching (SCB) which will affect the microstructure of polymer, as well as both physical and optical properties. Physical properties are evaluated such as dart drop impact, film impact, tensile strength, and elongation. Optical properties such as gloss and haze are also evaluated. Physical properties tend to have a better result along with the length of SCB. Meanwhile, the optical properties have a better result when the SCB is shorter. The result of the study exhibits that the type of co‐monomer in HDPE affects the quality of the film in terms of physical and optical properties.

Properties evaluation of biochar/high-density polyethylene composites: Emphasizing the porous structure of biochar by activation

Activated biochars (AB-0.5, AB-1, AB-1.5, AB-2) prepared under different concentrations of an activating agent were used to manufacturing composites (ABHC-0.5, ABHC-1, ABHC-1.5, ABHC-2) based on high-density polyethylene (HDPE) by compounding and injection molding. Thermal and mechanical properties of the composites were characterized and analyzed. The addition of activated biochars improved the thermal properties of HDPE shown by Differential scanning calorimetry and Thermogravimetric analysis. Additionally, ABHC-0.5 exhibited the best flexural strength (38.66 MPa), flexural modulus (2.46 GPa), tensile strength (32.17 MPa), tensile modulus (1.95 GPa), rigidity, elasticity, creep resistance, and anti-stress relaxation ability due to the best porous structure of AB-0.5. A decrease of mechanical properties was observed in ABHC-1, ABHC-1.5, ABHC-2 compared to ABHC-0.5, which was due to the fact that the porous structure was damaged by an excessive activating agent. The results of this study provided a predictive insight in view of optimizing process parameters and establishing the meaningful relationship between biochar porous structure and its resulting composites.

Influence of chitosan on the mechanical and biological properties of HDPE for biomedical applications

High density polyethylene (HDPE) is widely used in biomedical field, except when strong cell-material interactions and high mechanical properties are required. To address this pitfall, two kinds of chitosan in different amounts were used as filler in the present research. Composites were prepared by melt extrusion process and their microstructural, thermal and mechanical properties were widely investigated. Also roughness and wettability were studied, as features of paramount importance in dictating cell response.Both types of chitosan endowed HDPE with higher Young modulus and lower elongation at break. Interestingly, fibroblast adhesion and viability were enhanced when a low amount of filler was used. The interaction of HDPE/chitosan composites with biological environment was investigated for the first time in order to assess the feasibility of these composites as materials for biomedical application.

Characterization of Wood and Graphene Nanoplatelets (GNPs) Reinforced Polymer Composites.

This paper investigates the utilization of commercial masterbatches of graphene nanoplatelets to improve the properties of neat polymer and wood fiber composites manufactured by conventional processing methods. The effect of aspect ratio of the graphene platelets (represented by the different number of layers in the nanoplatelet) on the properties of high-density polyethylene (HDPE) is discussed. The composites were characterized for their mechanical properties (tensile, flexural, impact) and physical characteristics (morphology, crystallization, and thermal stability). The effect of the addition of nanoplatelets on the thermal conductivity and diffusivity of the reinforced polymer with different contents of reinforcement was also investigated. In general, the mechanical performance of the polymer was enhanced at the presence of either of the reinforcements (graphene or wood fiber). The improvement in mechanical properties of the nanocomposite was notable considering that no compatibilizer was used in the manufacturing. The use of a masterbatch can promote utilization of nano-modified polymer composites on an industrial scale without modification of the currently employed processing methods and facilities.

The influence of polyethylene processing on the plastic containers blowing

The materials of this article are devoted to the study of the influence of polyethylene processing on the plastic containers blowing. The aim of the study was to investigate the influence of one-time processing on the properties of high-density polyethylene, used for packing of mineral oils, as well as the indication of opportunities to use recycled material in the manufacture of new packing. The material used in the study was high-density polyethylene (HDPE) and recycled polyethylene. In the course of research, it was found that the processing led to a deterioration of the thermal properties of the polymer material, and the difference in the amount of liquidity of raw materials compared with processed, was 47.7%, which is consistent with reference studies. The conditions used during the blowing process resulted in uniformity of the final product in thickness. The difference in wall thickness of products made from raw material and recycled material was within 0.02 mm. The smallest thickness of finished products was 0.66 mm for recycled material and 0.68 mm for raw materials.

Maleic anhydride grafted onto high density polyethylene with an enhanced grafting degree via monomer microencapsulation

High-density polyethylene (HDPE) is among the flexible polymers on account of its appropriate processability and adequate mechanical properties. Grafting reactive monomers such as glycidyl methacrylate (GMA) and maleic anhydride (MAH) onto polyethylene was one of the ultimate choices to improve the physicochemical properties of HDPE. MAH is an appropriate option for grafting onto HDPE owing to its low reactivity and it relatively undergoes a direct grafting onto the polymer. The grafting of MAH on HDPE copolymerization has been conducted using monomer microencapsulation method in this study. The monomer microencapsulation samples were extracted stratified using acetone and xylen. Samples were then analyzed using titration, melt flow rate, FTIR, DSC, TGA and C-NMR. The results showed the degree of paste monomer on HDPE with a microencapsulation method was greater when compared to the usual method. We were successfully improving the grafting degree of MAH onto HDPE by using a simple blending method. The pre-microencapsulated HDPE provided an increasing in grafting degree of 1.88% (HDPE-g-MAH) over the conventional one which shows the value of 1.39% (HDPE-g-MAH).

Green composites based on high density polyethylene and recycled coffee gunny: Morphology, thermal, and mechanical properties

In this study, recycled coffee gunny (RCG) was used to reinforce high density polyethylene (HDPE). Maleic anhydride grafted polyethylene (MAPE) was added as a compatibilizer. Moreover, the RCG was chemically treated to enhance the compatibility between fiber and HDPE matrix. A series of RCG reinforced composites were prepared and the effects of MAPE and chemical modification of RCG on the mechanical and thermal properties of HDPE were investigated. The results of thermal and mechanical properties of composites revealed that the increments of heat deflection temperature, tensile strength, and impact strength of HDPE were 16[Formula: see text]C, 19.64% and 43.63% by the addition of modified coffee gunny, respectively. It reveals that the HDPE was reinforced with the coffee gunny, and thus can effectively reuse the discarded resources.

A detailed survey for determination of the grafted semifluorinated acrylic compound effect on thermal, microstructural, free volume, mechanical and morphological features of HDPE

This study mainly aims to investigate the role of grafted semifluorinated acrylic compound in the crucial characteristic properties of high density polyethylene (HDPE). Graft copolymerization of the semifluorinated acrylic compound, 3,3,4,4,5,5,6,6,7,7,8,8,8-dodecafluoro-5-methyloctyl-4-(acryloyloxy) benzoate (ABCF13) onto HDPE within the different content levels of ABCF13 (5, 10, 15, 20, 30 and 40 %) was performed by bulk-melt polymerization method. The changes in the thermal, microstructural and free volume characteristics of graft coproducts with extent of grafting were investigated in detail by means of DSC, powder X-ray diffraction and PALS techniques, respectively. The experimental findings showed that the melting temperature of crystalline domains and crystallinity ofHDPE reached the maxima at the 15 % and 40 % ABCF13 contents, respectively. The grafting of ABCF13 onto HDPE also gave rise to significant expansion and contraction in lateral dimensions of orthorhombic unit cell parameters in the crystalline domains of HDPE. Moreover, PALS analyses depicted that the size of the free volumes increased almost linearly with the grafting percentage. As for mechanical behaviours of the graft products, remarkable improvements were achieved in especially tensile strength (from 18.75 MPa to 43.75 MPa) and impact strength (from 19.30 Mpa to 38.72 MPa). The morphological properties of the fractured surfaces obtained from tensile and impact tests of products were also examined by SEM analysis. The samples possessed completely homogeneous structure without any phase separation. A gradual transition from ductile behaviour to brittle nature was observed as the grafting level increased in the products.

Impact of Graphite on Thermomechanical, Mechanical, Thermal, Electrical Properties, and Thermal Conductivity of HDPE/Copper Composites

AbstractImpact of graphite on the physicochemical properties of high density polyethylene (HDPE)/copper composites has been investigated at various volume percentages of copper. The two sets of composites are prepared by simple melt blending and injection molding approach. Thermal conductivity increases from 0.5 W m−1 K−1 for pure HDPE to 6.5 and 8 Wm−1 K−1 for 30 and 40 vol.% of copper loading with and without graphite, respectively. A huge increment in synergistic efficiency has been evidenced for the mixed filled polymer composites. Incorporation of graphite has also improved the percolation threshold from 19 to 13 vol.% of copper loading to the HDPE matrix, which indicates the synergistic effect of mixed filler system. Development of leafy morphology of copper promotes large number of inter‐particle contacts and hence improves the percolation threshold of the composites. The corrosion resistive, mechanically robust, electrically and thermally conductive composites with good flexural properties and light in weight than conventional metallic bipolar plates suggest it a material of choice for fuel cell devices.

Thermo-mechanical properties of high density polyethylene with zinc oxide as a filler

This study investigates the microstructural, thermal, and mechanical behavior of high density polyethylene (HDPE)-based composites prepared using compression molding technique. HDPE was mixed with either micro-size zinc oxide (bulk ZnO) or zinc oxide nanoparticles (nano-ZnO) as fillers’ contents at 0, 10, 20, 30, and 40 wt%. The structural, morphological, and thermal properties of the composites were identified using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectrophotometer (FTIR), and thermal gravimetric analysis (TGA). The results showed good dispersion and interaction mechanisms between HDPE and the fillers at low weight percentage. The thermal stability of HDPE was enhanced by adding both bulk and nano-ZnO, especially for higher filler loading. Tensile tests at different speeds and Vickers microhardness tests conducted at different indentation loads (0.25–5 N) at t = 60 s were performed to realize how the mechanical properties of the composites were influenced. The values of stiffness, ultimate tensile strength, and yield stress increased by increasing the filler loading to 20 wt% of either bulk ZnO or nano-ZnO. The values of ultimate tensile strain and ductility were deteriorated by increasing the filler loading. Nano-ZnO, at 20 wt% content in composite, showed higher mechanical properties than bulk composite, so it has been recommended for a better tensile performance at higher strain rates. Vickers microhardness measurements showed that the tested samples exhibited reverse indentation size effect (RISE) behavior. The obtained results were analyzed using Meyer’s law which was a preferred approach for analysis of HDPE/ZnO composite.