Tuning the Mechanical Properties of High-Density Polyethylene by ECAE Process

2015 ◽  
Author(s):  
Catalin Fetecau ◽  
Felicia Stan ◽  
Laurentiu Sandu ◽  
Florin Susac
Keyword(s):  
Mechanical Properties ◽  
High Density Polyethylene ◽  
Equal Channel Angular Extrusion ◽  
Morphological Changes ◽  
Longitudinal Axis ◽  
High Density ◽  
Scanning Calorimetry ◽  
Plastic Deformations ◽  
The Third ◽  
Indentation Tests

This paper investigates the ability of the equal channel angular extrusion (ECAE) process to induce morphological changes and hence tune the mechanical properties of high-density polyethylene (HDPE). In this study, differential scanning calorimetry (DSC), compression and cylindrical macro-indentation tests have been used to investigate the evolution of the mechanical properties of HDPE processed by ECAE up to four passes via route BC, i.e. counter clockwise 90° billet rotation about its longitudinal axis. It was found that the ECAE process induces significant plastic deformations with changes in the crystalline structure. The ECAE process increased the HDPE crystallinity by 10 to 15%. The number of ECAE passes has a significant effect on the magnitude of the mechanical properties especially on the elastic modulus and yield stress. Young’s modulus and yield strength decreased with increasing the number of ECAE passes and reached a stationary state after the third pass.

Morphological characterization, thermal, and mechanical properties of compatibilized high density polyethylene/polystyrene/organobentonite ternary nanocomposites

2018 ◽  
Vol 38 (9) ◽  
pp. 827-837 ◽  
Author(s):  
Farida Yahiaoui ◽  
Ouahida Bensebia ◽  
Assia Siham Hadj-Hamou
Keyword(s):  
Mechanical Properties ◽  
High Density Polyethylene ◽  
Morphological Changes ◽  
Tensile Modulus ◽  
Bentonite Clay ◽  
Morphological Characterization ◽  
High Density ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Melt Mixing

Abstract Composite materials made from high density polyethylene (HDPE) and polystyrene (PS) were successfully prepared in different HDPE/PS weight ratios, by melt mixing 3 wt% of bentonite clay organically modified with hexadecyl ammonium chloride (organo-modified bentonite, OBT). The structure and morphology of these composites were examined by X-ray diffraction and scanning electron microscopy. Morphological changes between the composite and the constituent materials were observed. The decrease in PS (or HDPE) particle size in HDPE/PS 70/30 (or 30/70) that blend after the OBT addition reflects a clear improvement in the HDPE/PS blend compatibility. The effect of OBT on the thermal and mechanical properties was investigated by differential scanning calorimetry, thermogravimetric analysis, and tensile measurements. The main results show a decrease in the HDPE crystallinity in the composite matrices, which reaches 25% for HDPE/PS/OBT 29/68/3 composite, also an improvement of the thermal stability, as evidenced by the higher Tonset values, and finally a reinforcement of the tensile properties as compared to the unfilled blends. Indeed, a significant enhancement of the tensile modulus (~130%) is observed for the 68/29/3 composite matrix as compared to the 70/30 unfilled blend.

Effect of Silane Coupling Agents on Mechanical Properties of Nano-SiO2 Filled High-Density Polyethylene Composites

2007 ◽  
Vol 555 ◽  
pp. 479-484 ◽  
Author(s):  
D. Stojanović ◽  
P. S. Uskoković ◽  
I. Balać ◽  
V.J. Radojević ◽  
R. Aleksić
Keyword(s):  
Mechanical Properties ◽  
High Density Polyethylene ◽  
Particle Surface ◽  
High Density ◽  
Coupling Agents ◽  
Stress Concentrations ◽  
Silane Coupling Agents ◽  
Silane Coupling ◽  
The Matrix ◽  
Indentation Tests

Composites with nano-SiO2 particles and high density polyethylene (HDPE) matrix were produced by hot pressing with various particle contents and particle surface treatment using commercially available silane coupling agents: γ-methacryloxypropyltrimethoxy silane and γ- glycidyloxypropyltrimethoxysilane. The influence of the particle treatment on the mechanical properties of composites was determined by compression and indentation tests. Additionally, numerical analysis was performed in order to calculate Young’s modulus and stress concentrations for various particle contents in order to provide reference data by simulating micro- and macro particle composites with perfect bonding to the matrix.

scholarly journals Mechanical Properties, Wettability and Thermal Degradation of HDPE/Birch Fiber Composite

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1459
Author(s):  
Agbelenko Koffi ◽  
Fayçal Mijiyawa ◽  
Demagna Koffi ◽  
Fouad Erchiqui ◽  
Lotfi Toubal
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Thermal Degradation ◽  
Coupling Agent ◽  
High Density Polyethylene ◽  
Fiber Composite ◽  
Flexural Modulus ◽  
High Density ◽  
Wood Fibers ◽  
Scanning Calorimetry

Wood–plastic composites have emerged and represent an alternative to conventional composites reinforced with synthetic carbon fiber or glass fiber–polymer. A wide variety of wood fibers are used in WPCs including birch fiber. Birch is a common hardwood tree that grows in cool areas such as the province of Quebec, Canada. The effect of the filler proportion on the mechanical properties, wettability, and thermal degradation of high-density polyethylene/birch fiber composite was studied. High-density polyethylene, birch fiber and maleic anhydride polyethylene as coupling agent were mixed and pressed to obtain test specimens. Tensile and flexural tests, scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetry analysis and surface energy measurement were carried out. The tensile elastic modulus increased by 210% as the fiber content reached 50% by weight while the flexural modulus increased by 236%. The water droplet contact angle always exceeded 90°, meaning that the material remained hydrophobic. The thermal decomposition mass loss increased proportional with the percentage of fiber, which degraded at a lower temperature than the HDPE did. Both the storage modulus and the loss modulus increased with the proportion of fiber. Based on differential scanning calorimetry, neither the fiber proportion nor the coupling agent proportion affected the material melting temperature.

Exploration on compatibilizing effect of nonionic, anionic, and cationic surfactants on mechanical, morphological, and chemical properties of high-density polyethylene/low-density polyethylene/cellulose biocomposites

2015 ◽  
Vol 30 (6) ◽  
pp. 855-884 ◽  
Author(s):  
AK Sudari ◽  
AA Shamsuri ◽  
ES Zainudin ◽  
PM Tahir
Keyword(s):  
Mechanical Properties ◽  
High Density Polyethylene ◽  
Sodium Stearate ◽  
High Density ◽  
Low Density Polyethylene ◽  
Hexadecyltrimethylammonium Bromide ◽  
Low Density ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Compatibilizing Effect

Three types of surfactants, specifically cationic, anionic, and nonionic, at different weight percentages were added into high-density polyethylene/low-density polyethylene/cellulose (HDPE/LDPE/cellulose) biocomposites via melt mixing. The cationic and anionic surfactants which are hexadecyltrimethylammonium bromide (HTAB) and sodium stearate (SS), respectively, were added from 4 to 20 wt%, whereas the nonionic surfactant which is sorbitan monostearate (SM) was added from 1 to 5 wt%. The mechanical testing results exhibited that the addition of HTAB increased tensile strength and tensile modulus, while SS deteriorated mechanical properties, while SM increased impact strength and tensile extension of the biocomposites. Based on the mechanical properties results, optimum weight percentages of HTAB and SM were 12 wt% and 4 wt%, respectively. The scanning electron microscopic micrographs displayed that the amount of cellulose fillers pullout decreased with the addition of HTAB, followed by SM, but it increased with SS. Fourier transform infrared spectra, X-ray diffractometer patterns, thermogravimetric analysis results, and differential scanning calorimetry thermograms have confirmed the presence of physical interactions only with the addition of HTAB and SM. Based on the results, compatibilizing effect was found in HTAB, whereas SM has not showed compatibilizing effect but instead plasticizing effect. However, neither compatibilizing nor plasticizing effect was exhibited by SS.

scholarly journals Durability of Basalt/Hemp Hybrid Thermoplastic Composites

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 603 ◽  
Author(s):  
Claudia Sergi ◽  
Jacopo Tirillò ◽  
Maria Carolina Seghini ◽  
Fabrizio Sarasini ◽  
Vincenzo Fiore ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Uv Radiation ◽  
High Density Polyethylene ◽  
High Density ◽  
Thermoplastic Composites ◽  
Accelerated Ageing ◽  
Special Focus ◽  
Scanning Calorimetry ◽  
Hemp Fibre ◽  
Fibre Composites

The Achilles heel of thermoplastic natural fibre composites is their limited durability. The environmental degradation of the mechanical properties of hemp and hemp/basalt hybrid-reinforced high-density polyethylene (HDPE) composites has been investigated with a special focus on the effects of water ageing and accelerated ageing, including hygrothermal and UV radiation. Modification of the matrix was carried out using a maleic anhydride high-density polyethylene copolymer (MAPE) as a compatibilizer. Hybridization of hemp fibres with basalt fibres and the incorporation of MAPE were found to significantly decrease the water uptake (up to 75%) and increase the retention of mechanical properties after accelerated ageing. Secondary crystallization phenomena occurring in the composites, as confirmed by differential scanning calorimetry (DSC) analysis, were able to counteract the severe combined effects of hygrothermal stress and UV radiation, with the exception of hemp-fibre composites where permanent damage to the fibres occurred, with 2% and 20% reduction in tensile strength and modulus, respectively, for a 30 wt % hemp fibre-reinforced HDPE.

Role of Multiwalled Carbon Nanotube on Mechanical Reinforcement of High-Density Polyethylene

2013 ◽  
Vol 652-654 ◽  
pp. 15-24 ◽  
Author(s):  
Xia Ran Miao ◽  
Yuan Jiang Qi ◽  
Xiao Yun Li ◽  
Yu Zhu Wang ◽  
Xiao Long Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
High Density Polyethylene ◽  
High Density ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Multiwalled Carbon ◽  
Mechanical Reinforcement ◽  
Multi Wall Carbon Nanotubes ◽  
X Ray Scattering

The high density polyethylene (HDPE) nanocomposites were prepared by melt mixing HDPE with multi-wall carbon nanotubes (MWCNTs). In this work, the morphological, nucleation, crystallization and mechanical properties of the HDPE nanocomposites were studied by scanning electron microscopy, different scanning calorimetry, small-angle X-ray scattering and tensile testing. It was found that the tensile strength and Young’s modulus is increased by 42.4% and 116.5% at 3.wt% MWCNT loading compared to the pure HDPE. According to SEM results combined with SAXS, well-defined nanohybird shish-kebab (NHSK) entities exist in the composites, and in the shish-kebab structures fibrillous carbon nanotubes (MWCNTs) act as shish while HDPE lamellae act as kebab. The crystallization behavior, probed by DSC, suggests that MWCNTs have strong nucleation ability and shear stress plays an important role in polymer crystallization process. The mechanical properties demonstrated that the formation of the Shish-kebab structures improved the interfacial adhesion and brought obvious mechanical enhancement for the HDPE/MWCNTs nanocomposites.

Effect of waste polyethylene terephthalate content on the durability and mechanical properties of composites with tire rubber matrix

2016 ◽  
Vol 51 (3) ◽  
pp. 357-372 ◽  
Author(s):  
Mihaela Cosnita ◽  
Cristina Cazan ◽  
Anca Duta
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
High Density Polyethylene ◽  
Water Immersion ◽  
High Density ◽  
Rubber Matrix ◽  
Scanning Calorimetry ◽  
Long Time ◽  
Waste Polyethylene ◽  
Prior Application

The paper investigates new composites fully based on wastes of polyethylene terephthalate, rubber, high-density polyethylene, and wood, aiming at multifunctional, environmental-friendly materials, for indoor and outdoor applications. The rubber: polyethylene terephthalate: high-density polyethylene: wood ratio and compression molding temperatures are optimized considering the output mechanical properties, focusing on increasing the waste polyethylene terephthalate content. To investigate the durability in the working conditions, the water-stable composites, with good tensile and compression strengths were exposed to surfactant systems, saline aerosols, and ultraviolet radiations. The results prove that surfactant immersion improves the interfaces and the mechanical properties and a pre-conditioning step involving the dodecyltrimethylammonium bromide surfactant is recommended, prior application. The interfaces and the bulk composites were investigated by X-ray diffraction, Fourier-transform infrared, differential scanning calorimetry, contact angle measurements, scanning electron microscopy, atomic force microscopy, to identify the properties that influence the mechanical behavior and durability. The composites containing 30% of polyethylene terephthalate, obtained at 160℃ and 190℃ have a good combination of mechanical properties and durability that is enhanced by the plasticizing effect of water and surfactants. The compressive strength of the composite processed at 190℃ was 51.2 MPa and the value increased to 58.4 MPa after water immersion. The ultraviolet and saline exposure slightly diminished this effect; however, long time testing (120 h) ended up with values higher than those corresponding to the pristine composite: 55.3 MPa after ultraviolet and 57.1 MPa after saline exposure.

Long-term closed-loop recycling of high-density polyethylene/flax composites

2018 ◽  
Vol 34 (4) ◽  
pp. 171-199 ◽  
Author(s):  
Nathalie Benoit ◽  
Rubén González-Núñez ◽  
Denis Rodrigue
Keyword(s):  
Mechanical Properties ◽  
Coupling Agent ◽  
High Density Polyethylene ◽  
Closed Loop ◽  
Fibre Length ◽  
Chain Scission ◽  
High Density ◽  
Scanning Calorimetry ◽  
Initial Processing

This work investigates the loss of performance and the recyclability of natural fibre composites for a long-term closed-loop process. Composites based on flax fibres and high-density polyethylene are subjected up to 50 extrusion cycles under constant processing conditions with or without maleic anhydride grafted polyethylene as a coupling agent. The results show that the addition of fibre increases the rigidity but decreases the elongation properties. The initial processing cycle leads to an important decrease of the fibre length and modification of the molecular weight distributions, thus indicating that the addition of fibre enhances chain scission and that fibre breakup mainly happens during the initial processing. The effect of recycling is much less significant, except for the mechanical properties. Negligible variations are observed for density, differential scanning calorimetry, thermogravimetric analysis, gel permeation chromatography and impact results. On the contrary, the mechanical properties are strongly affected by recycling as most of them increase with recycling. The addition of a coupling agent improves the composite properties, but this effect disappears with recycling. These trends are associated to a balance between fibre breakup and macromolecular chain scission compared to more homogeneous materials (better fibre distribution) taking place in the materials during recycling. The results show that long-term recycling of composites is possible as their overall performances remain acceptable.

scholarly journals Structure and Mechanical Properties of High-Density Polyethylene Composites Reinforced with Glassy Carbon

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4024
Author(s):  
Piotr Olesik ◽  
Marcin Godzierz ◽  
Mateusz Kozioł ◽  
Jakub Jała ◽  
Urszula Szeluga ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Glassy Carbon ◽  
High Density Polyethylene ◽  
Mechanical Performance ◽  
High Density ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Carbon Fillers ◽  
Composite Samples

In this paper, we investigated theimpact of glassy carbon (GC) reinforcement oncrystal structure and the mechanical performance of high-density polyethylene (HDPE). We made composite samples by mixing HDPE granules with powder in ethanol followed bymelt mixing in a laboratory extruder. Along with the investigated composite, we also prepared samples with carbon nanotubes (CNT), graphene (GNP) and graphite (Gr) to compare GC impact with already used carbon fillers. To evaluate crystal structure and crystallinity, we used X-ray diffraction (XRD) and differential scanning calorimetry (DSC). We supported the XRD results with a residual stress analysis (RSA) according to the EN15305 standard. Analysis showed that reinforcing with GC leads to significant crystallite size reduction and low residual stress values. We evaluated the mechanical properties of composites with hardness and tensile testing. The addition of glassy carbon results inincreased mechanical strength incomposites with CNT and GNP.

Measurement and Analysis on Tensile Strength and Crystallinity of Vibrating Extruded High-Density Polyethylene (HDPE) Sheet

2011 ◽  
Vol 291-294 ◽  
pp. 561-564
Author(s):  
Bao Shan Shi ◽  
Xue Mei Qin ◽  
Bing Li
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Low Temperature ◽  
High Density Polyethylene ◽  
High Density ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Scanning Electron Microcopy ◽  
Measurement And Analysis ◽  
Result Show

By the apparatus of differential scanning calorimetry (DSC), scanning electron microcopy (SEM) and wide angle X-ray diffraction (WAXD), The effect of vibration on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through vibration plasticating extruder in low temperature, were measured and analysed. The result show that the tensile strength was much improved under the reciprocating axial vibration in low temperature. The phenomenon indicate that the vibration extrudate in low temperature has higher crystallinity, perfect crystallite, and strong inter-spherulite ties, which account for enhancement of the mechanical properties of sheets, compared to conventional static extrusion.

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