Influence of Thermal Ratcheting on the Creep and Mechanical Properties of High-Density Polyethylene

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Rahul Palaniappan Kanthabhabha Jeya ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Creep Strain ◽  
High Density Polyethylene ◽  
Coefficient Of Thermal Expansion ◽  
Creep Property ◽  
High Density ◽  
Steady Creep ◽  
Thermal Cycles ◽  
Ratcheting Strain ◽  
Thermal Ratcheting ◽  
The Impact

Abstract The objective of this research is to describe the consequence of thermal ratcheting on the long-term creep property of the high-density polyethylene (HDPE) material. The thermal ratcheting phenomenon increases significantly the creep strain of HDPE. The magnitude of the creep strain of HDPE increases by 8% after just 20 thermal cycles between 28 and 50 °C. The creep modulus, which is inversely proportional to the creep strain, depletes further under thermal ratcheting. Both the properties change significantly with the number of thermal cycles. The coefficient of thermal expansion (CTE) of HDPE varies with the applied compressive load, with successive thermal cycles, and with the thermal ratcheting temperature. The impact of thermal ratcheting diminishes with an increase in initial steady creep exposure time period, but still the magnitude cumulative deformation induced is noteworthy. The magnitude of growth in creep strain drops from 8% to 2.4% when thermal ratcheting is performed after 1 and 45 days of steady creep, respectively. There is a notable change in the thickness of the material with each heating and cooling cycle even after 45 days of creep; however, the thermal ratcheting strain value drops by 80% in comparison with the thermal ratcheting strain after 1 day of creep and under similar test conditions.

Influence of Thermal Ratcheting on the Creep and Mechanical Properties of High Density Polyethylene (HDPE)

2018 ◽  
Author(s):  
Rahul Palaniappan Kanthabhabha Jeya ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Creep Strain ◽  
Coefficient Of Thermal Expansion ◽  
Creep Property ◽  
Compressive Load ◽  
Steady Creep ◽  
Thermal Cycles ◽  
Ratcheting Strain ◽  
Heating And Cooling ◽  
Thermal Ratcheting ◽  
The Impact

The objective of this research is to describe the consequence of thermal ratcheting on the long-term creep property of HDPE material. The thermal ratcheting phenomenon amplifies significantly the creep strain of HDPE in comparison to the steady creep strain under constant temperature. The magnitude of creep strain of HDPE increases by 8% after just 20 thermal cycles between 28 and 50°C. The creep modulus which is inversely proportional to the creep strain depletes further under thermal ratcheting. Both properties change significantly with the number of thermal cycles. The coefficient of thermal expansion (CTE) of HDPE varies with the applied compressive load, with successive thermal cycles and with the thermal ratcheting temperature. The impact of thermal ratcheting diminishes with increase in initial steady creep exposure time-period but still the magnitude cumulative damage induced is noteworthy. The magnitude of growth in creep strain drops from 8 to 2.4% when thermal ratcheting is performed after 1 and 45 days of steady creep, respectively. There is a notable change in thickness of the material with each heating and cooling cycle even after 45 days of creep however, the thermal ratcheting strain value drops by 80% in comparison to thermal ratcheting strain after 1 day of creep and under similar test conditions.

Characterisation of Polytetrafluoroethylene and Fiber Based Gaskets Under Creep and Thermal Ratcheting

2017 ◽  
Author(s):  
Rahul Palaniappan Kanthabhabha Jeya ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Research Work ◽  
Creep Property ◽  
Compressive Load ◽  
Cumulative Damage ◽  
Thermal Ratcheting ◽  
Different Temperatures ◽  
Leak Tightness ◽  
The Impact ◽  
Applied Stresses

The objective of this research work is to typify PolyTetraFluoroEthylene (PTFE) and fiber based gaskets. Recurrent employment of Teflon based gaskets as asbestos gasket replacement in certain applications is due to their effective leak tightness and excellent chemical resistance. The research investigates the effect of cyclic and determinant temperature on the phenomenon of creep and thermal ratcheting under compressive load. The tests are performed at 4000 and 6000 psi compressive stress on virgin PTFE (vPTFE) and expanded PTFE (ePTFE) along with Inorganic Fiber Gaskets (IFG) at different temperatures. The Universal Gasket Rig (UGR) is utilized to perform the convoluted analysis of creep-thermal ratcheting coupling at different stress levels on selected gasket materials. The actual cumulative damage due to thermal ratcheting is separable into upper and lower bound regions indicating the highest and lowest of ratcheting temperature regions. The effect of thermal ratcheting tends to saturate after 12 and 15 cycles for expanded PTFE and fiber gaskets while no saturation is observed with virgin PTFE gaskets even after 20 thermal cycles. IFG and virgin PTFE gaskets exhibited similar percentage of thickness reduction under different applied stresses while expanded PTFE showed a maximum reduction under the least applied stress. The influences of temperature and load are manifested in the compressive creep property which in turn dictates the magnitude of cumulative damage due to thermal ratcheting. Lastly, the impact of creep and thermal ratcheting on the Coefficient of Thermal Expansion (CTE) is evident as the magnitude of CTE upsurges with the extent of induced damage.

Evaluation of the Aging Behavior of High Density Polyethylene in Thermal Oxidative Environment by Principal Component Analysis

2017 ◽  
Vol 727 ◽  
pp. 447-449 ◽  
Author(s):  
Jun Dai ◽  
Hua Yan ◽  
Jian Jian Yang ◽  
Jun Jun Guo
Keyword(s):  
Principal Component Analysis ◽  
Impact Strength ◽  
High Density Polyethylene ◽  
Tensile Modulus ◽  
Principal Component ◽  
Component Analysis ◽  
High Density ◽  
Aging Behavior ◽  
Data Set ◽  
The Impact

To evaluate the aging behavior of high density polyethylene (HDPE) under an artificial accelerated environment, principal component analysis (PCA) was used to establish a non-dimensional expression Z from a data set of multiple degradation parameters of HDPE. In this study, HDPE samples were exposed to the accelerated thermal oxidative environment for different time intervals up to 64 days. The results showed that the combined evaluating parameter Z was characterized by three-stage changes. The combined evaluating parameter Z increased quickly in the first 16 days of exposure and then leveled off. After 40 days, it began to increase again. Among the 10 degradation parameters, branching degree, carbonyl index and hydroxyl index are strongly associated. The tensile modulus is highly correlated with the impact strength. The tensile strength, tensile modulus and impact strength are negatively correlated with the crystallinity.

Effect of inorganic nanofillers on the impact behavior and fracture probability of industrial high-density polyethylene nanocomposite

2017 ◽  
Vol 52 (18) ◽  
pp. 2431-2442 ◽  
Author(s):  
Harun Sepet ◽  
Necmettin Tarakcioglu ◽  
RDK Misra
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Density Polyethylene ◽  
Fracture Probability ◽  
High Density ◽  
Impact Behavior ◽  
Inorganic Filler ◽  
Melt Mixing ◽  
The Impact ◽  
Scanning Electron

The main purpose of this work is to study how the morphology of nanofillers and dispersion and distribution level of inorganic nanofiller influence the impact behavior and fracture probability of inorganic filler filled industrial high-density polyethylene nanocomposites. For this study, nanoclay and nano-CaCO3 fillers–high-density polyethylene mixings (0, 1, 3, 5 wt.% high-density polyethylene) was prepared by melt-mixing method using a compounder system. The impact behavior was examined by charpy impact test, scanning electron microscopy, and probability theory and statistics. The level of the dispersion was characterized with scanning electron microscopy energy dispersive X-ray spectroscopy analysis. The results showed rather good dispersion of both of inorganic nanofiller, with a mixture of exfoliated and confined morphology. The results indicated that the impact strength of the industrial nanocomposite decreased with the increase of inorganic particulate content. The impact reliability of the industrial nanocomposites depends on the type of nanofillers and their dispersion and distribution in the matrix.

Pre-Fibrillation of Pulps to Manufacture Cellulose Nanofiber Reinforced High-Density Polyethylene using the Dry-Pulp Direct Kneading Method

2021 ◽  
Author(s):  
Yuko Igarashi ◽  
Akihiro Sato ◽  
Hiroaki Okumura ◽  
Fumiaki Nakatsubo ◽  
Takashi Kuboki ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
Coefficient Of Thermal Expansion ◽  
Tensile Modulus ◽  
Cellulose Fibers ◽  
High Density ◽  
Cellulose Nanofiber ◽  
Feed Material ◽  
Alkenyl Succinic Anhydride ◽  
Melt Compounding ◽  
Kneading Method

Abstract The dry-pulp direct-kneading method is an industrially viable, low-energy process to manufacture cellulose nanofiber (CNF) reinforced polymer composites, where chemically modified pulps can be nanofibrillated and dispersed uniformly in the polymer matrix during melt-compounding. In this study, cellulose fibers with different sizes, ranging from surface-fibrillated pulps with 20 µm in width to fine CNFs with 20 nm in width were prepared from softwood bleached kraft pulps (NBKPs) using a refiner and high-pressure homogenizer (HPH). These cellulose fibers were modified with alkenyl succinic anhydride (ASA), and then dried. The dried ASA-treated cellulose fibers were used as a feed material for melt-compounding in the dry-pulp direct kneading method to fabricate CNF reinforced high-density polyethylene (HDPE). When surface-fibrillated pulps were employed as a feed material, the pulps were nanofibrillated and dispersed uniformly in the HDPE matrix during the melt-compounding, and the composites had much better properties (i.e., much higher tensile modulus and strength and much lower coefficient of thermal expansion) than the composites produced using the pulps without pre-fibrillation. However, when CNFs were used as a feed material, the CNFs were shortened and agglomerated during the melt-compounding, thus deteriorating the properties of the composites. The study concludes that the pre-fibrillation of pulps had a significant impact on the morphology and properties of the composites. Unexpectedly, the surface-fibrillated pulp, which can be produced cost-effectively using a refiner at an industry scale, was a more suitable form than the CNF as a feed material for melt-compounding in the dry-pulp direct kneading method.

scholarly journals Impact of Polymer Binders on the Structure of Highly Filled Zirconia Feedstocks

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2247
Author(s):  
Claire Delaroa ◽  
René Fulchiron ◽  
Eric Lintingre ◽  
Zoé Buniazet ◽  
Philippe Cassagnau
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
High Density Polyethylene ◽  
Mercury Porosimetry ◽  
High Density ◽  
Organic Binder ◽  
Molten State ◽  
Homogeneous Dispersion ◽  
The Impact

The impact of polypropylene and high-density polyethylene backbone binders on the structure of organic matrix, feedstock, and ceramic parts is investigated in terms of morphology in this paper. The miscibility of wax with polyethylene and polypropylene is investigated in the molten state via a rheological study, revealing wax full miscibility with high-density polyethylene and restricted miscibility with polypropylene. Mercury porosimetry measurements realized after wax extraction allow the characterization of wax dispersion in both neat organic blends and zirconia filled feedstocks. Miscibility differences in the molten state highly impact wax dispersion in backbone polymers after cooling: wax is preferentially located in polyethylene phase, while it is easily segregated from polypropylene phase, leading to the creation of large cracks during solvent debinding. The use of a polyethylene/polypropylene ratio higher than 70/30 hinders wax segregation and favors its homogeneous dispersion in organic binder. As zirconia is added to organic blends containing polyethylene, polypropylene, and wax, the pore size distribution created by wax extraction is shifted towards smaller pores. Above zirconia percolation at 40 vol%, the pore size distribution becomes sharp attesting of wax homogeneous dispersion. As the PP content in the organic binder decreases from 100% to 0%, the pore size distribution is reduced of 30%, leading to higher densification ability. In order to ensure a maximal densification of the final ceramic, polyethylene/polypropylene ratios with a minimum content of 70% of high-density polyethylene should be employed.

Mechanical Properties and Thermal Conductivity of Coal Ash-Recycled High-Density Polyethylene Composite

2018 ◽  
Vol 06 (01n02) ◽  
pp. 1850002
Author(s):  
Ban M. Alshabander ◽  
Awattif A. Mohammed ◽  
Asmaa Sh. Khalil
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
High Density Polyethylene ◽  
Waste Product ◽  
Construction Materials ◽  
Coal Ash ◽  
High Density ◽  
Plastic Composite ◽  
The Impact ◽  
Recycled Hdpe

In this study, coal ash/recycled plastic composite material was fabricated with post-consumer high-density polyethylene (HDPE) and coal ash particles. The main idea of using coal ash, since it is also a waste product, as reinforcing filler in recycled HDPE is to reduce the cost, develop lightweight and produce environmental-friendly materials. Coal ash/recycled plastic composite have been used in significant applications as construction materials including flooring, landscaping, fencing, railing window framing and roof tiles. Effect of coal ash loading on the mechanical properties and thermal conductivity of coal ash/recycled HDPE composite were determined. It is expected to use waste materials in new field by getting novel composite materials with developed mechanical properties. It was found that coal ash filler indicated significant improvement on the mechanical properties of composites. The results show that the impact decreased tremendously from 57.32 to 15.8[Formula: see text]kJ/m2 with only 30[Formula: see text]wt.% loading of coal ash. The filler increases the elasticity of the material and reduces its ability to absorb deformation energy.

Performance characteristics of polyethylene/old corrugated container composites reinforced with carbon nanotubes

2016 ◽  
Vol 51 (18) ◽  
pp. 2665-2673 ◽  
Author(s):  
Behzad Kord ◽  
Mehdi Roohani
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
High Density Polyethylene ◽  
Analysis Data ◽  
High Density ◽  
Scanning Calorimetry ◽  
Polyethylene Matrix ◽  
Melt Compounding ◽  
The Impact ◽  
Thermal Stability Of

The physical, mechanical, thermal, and flammability properties of high-density polyethylene/old corrugated container composites reinforced with carbon nanotubes are presented in this study. High-density polyethylene/old corrugated container composites with different loadings of carbon nanotube (0, 1, 3, and 5 phc) were prepared by melt compounding followed by injection molding. Results indicated that the incorporation of carbon nanotube into high-density polyethylene, significantly improved the mechanical properties of the composites. The tensile and flexural properties achieved the maximum values when 3 phc carbon nanotube was added. Meanwhile, the impact strength of the composites progressively decreased with increasing carbon nanotube content. Furthermore, the water absorption and thickness swelling of the samples remarkably reduced with the addition of carbon nanotube. From thermogravimetric analysis data, the presence of carbon nanotube could enhance the thermal stability of the composites, especially the maximum weight loss rate temperature and also the better char residual was obtained at high loading level of carbon nanotube. Simultaneous differential scanning calorimetry thermograms revealed that the thermal degradation temperatures for the samples with carbon nanotube were much higher than those made without carbon nanotube. Moreover, it was found that the addition of carbon nanotube results in a significant enhancement in flame retardancy of the composites. Morphological observations showed that the nanoparticles were predominantly dispersed uniformly within the high-density polyethylene matrix.

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