Effect of bark flour on viscoelastic behavior of high density polyethylene

2010 ◽  
Vol 45 (9) ◽  
pp. 1007-1016 ◽  
Author(s):  
Kamini Sewda ◽  
S.N. Maiti
Keyword(s):  
Storage Modulus ◽  
High Density Polyethylene ◽  
Volume Fraction ◽  
Viscoelastic Behavior ◽  
Peak Shift ◽  
High Density ◽  
Mechanical Restraint ◽  
Higher Temperature ◽  
Tan Δ ◽  
Damping Peak

The dynamic mechanical behavior of high density polyethylene (HDPE) in HDPE/bark flour (BF) composites on varying the volume fraction (Φf) of BF (filler) from 0 to 0.26 has been studied. The storage modulus decreases with increase in BF content up to Φf = 0.07, which is attributed to a pseudolubricating effect by the filler. The storage modulus for the composites at Φ f = 0.20 is higher than HDPE in all other temperature zones due to enhanced mechanical restraint by the dispersed phase. At Φf = 0.07, the loss moduli were either marginally lower or similar to that of HDPE, which is due to the ball-bearing effect of the filler as well as decrease in the crystallinity of HDPE. Above Φf = 0.07, the loss moduli were higher than HDPE. The α-relaxation region of the damping peak shifted toward the higher temperature side with increase in BF content. In the presence of the coupling agent, maleic anhydride-grafted HDPE (HDPE-g-MAH), the storage modulus values were marginally lower than those of the HDPE/BF systems. In the HDPE/BF/HDPE—g—MAH composites, the variations of the loss moduli were similar but values lower than those of the HDPE/BF systems. Damping peak shift in the α-region toward higher temperature was more than those of the HDPE/BF systems, which may be due to the hindrance to the relaxation due to an enhanced phase interaction. The values of tan δ were higher than the rule of mixture for both the composites.

Influence of eco-friendly pretreatment of lignocellulosic biomass using ionic liquids on the interface adhesion and characteristics of polymer composite boards

2020 ◽  
Vol 54 (25) ◽  
pp. 3717-3729 ◽  
Author(s):  
Behzad Kord ◽  
Farnaz Movahedi ◽  
Laleh Adlnasab ◽  
Hassan Masrouri
Keyword(s):  
Ionic Liquids ◽  
High Density Polyethylene ◽  
Wood Flour ◽  
Treated Wood ◽  
Interfacial Strength ◽  
Untreated Wood ◽  
High Density ◽  
Interfacial Behavior ◽  
Higher Temperature ◽  
Tan Δ

In this investigation, the effect of ionic liquids (ILs) pretreatment on the interfacial behavior, physical, and thermal properties of compression-molded composite boards produced from wood flour and high-density polyethylene was studied. Firstly, wood flour was pretreated with with two types of synthesized ILs, namely 1-(3-trimethoxysilylpropyl)-3-methylimidazolium chloride (IL-Cl) and 1-(3-trimethoxysilylpropyl)-3-methylimidazolium thiocyanate (IL-SCN). Thereafter, the interfacial strength, weight loss, water absorption, and thickness swelling of the specimens prepared from untreated and ILs-treated were evaluated. Further, the chemical treatment of wood flour with ILs was tracked by Fourier transform infrared spectroscopy. The morphological aspects of the specimens were characterized using Field Emission Scanning Electron Microscope (FESEM). Results demonstrated that the strong interaction between the wood flour and high-density polyethylene occurred in the presence of ILs pretreatment, which corresponded with the minimum amounts of adhesion factor. The tan δ peak was shifted to higher temperature for the modified samples than unmodified ones. It was noted that thermal stability of the composite boards improved as a result of ILs pretreatment. The residual weight in temperature of 600℃ was increased to 21.09% and 17.28% for the composite panels made from IL-SCN- and IL-Cl-treated wood, respectively, as compared to a residual mass of 16.35% for the composite based on untreated wood. Furthermore, physical testing revealed that the specimens produced from ILs-treated wood exhibited superior water resistance and dimensional stability compared to that of untreated ones.

Coupling of Nanocavitation With Cyclic Deformation Behavior of High-Density Polyethylene Below the Yield Point

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Kamel Hizoum ◽  
Yves Rémond ◽  
Stanislav Patlazhan
Keyword(s):  
Yield Point ◽  
High Density Polyethylene ◽  
Volume Fraction ◽  
Viscoelastic Behavior ◽  
High Density ◽  
Model Parameters ◽  
Mechanical Modeling ◽  
Lower Stress ◽  
Structure Sensitive ◽  
The Common

The peculiarities of viscoelastic behavior of high-density polyethylene (HDPE) subjected to the uniaxial cyclic tensions and retractions below the yield point are studied. This required using three different deformation programs including (i) the successive increase in strain maximum of each cycle, (ii) the controlled upper and lower stress boundaries, and (iii) the fixed strain at the backtracking points. The experimental data are analyzed in a framework of the modified structure-sensitive model (Oshmyan et al., 2006, “Principles of Structural–Mechanical Modeling of Polymers and Composites,” Polym. Sci. Ser. A, 48, pp. 1004–1013) of semicrystalline polymers. It is supposed that increase in the interlamellar nanovoid volume fraction results in speeding-up the plastic flow rate while decreasing cavitation rate. Consequently, a proper fitting of the stress–strain cyclic diagrams is obtained for the applied deformation programs within the common set of model parameters. This makes it possible to reveal evolution of nanovoid volume fraction in HDPE during cyclic deformations.

Poly(4-methyl-1-pentene)/MWNT nanocomposites

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Prashant A Patil ◽  
Santosh D Wanjale ◽  
Jyoti P. Jog
Keyword(s):  
Storage Modulus ◽  
Multiwall Carbon Nanotubes ◽  
Viscoelastic Behavior ◽  
Complex Viscosity ◽  
Dielectric Analysis ◽  
Melt Compounding ◽  
Tan Δ ◽  
Multiwall Carbon ◽  
Thermal Stability Of ◽  
Scanning Electron

AbstractNanocomposites of poly(4-methyl-1-pentene) (PMP) with various weight fractions of multiwall carbon nanotubes (MWNT’s) were prepared by melt compounding. The nanocomposites are characterized for structure using scanning electron microscopy. The viscoelastic behavior of the nanocomposites is investigated in solid as well as melt state. The study reveals a significant increase in storage modulus especially in the rubbery regime of the polymer matrix and reduced tan δ. Rheological properties in melt show that the complex viscosity and shear storage modulus are increased as a result of incorporation of MWNT. A systematic decrease in the cross over frequency is noted which is attributed to the increased relaxation time. In dielectric analysis, composition dependent enhanced permittivity and conductivity are observed. The thermal stability of the polymer is found to be significantly improved in presence of MWNT’s.

Mathematical modeling of viscoelastic material under impact load

2019 ◽  
Vol 54 (2) ◽  
pp. 130-138
Author(s):  
Md Fazlay Rabbi ◽  
Vijaya B Chalivendra
Keyword(s):  
Storage Modulus ◽  
Viscoelastic Material ◽  
Impact Force ◽  
Impact Load ◽  
Viscoelastic Behavior ◽  
Maximum Displacement ◽  
Drop Weight ◽  
Tan Δ ◽  
The One ◽  
The Impact

A linear physics-based model is developed to investigate the one-dimensional impact on a viscoelastic material. A generalized model with three Maxwell elements is considered to describe the viscoelastic behavior. An analytical method based on Laplace transformation is used to solve the impact problem. To have a comprehensive understanding of viscoelastic material response, drop-weight impact is also considered in this study. For both linear impact and drop-weight cases, a maximum reduction of 15% of the impact force as well as 32% higher energy absorption can be achieved with the increase in tan δ from 0.01 to 0.8 of viscoelastic material. In addition, for linear impact, impact force decreases by 20% when tan δ = 1. With the increase in tan δ, storage modulus decreases by around 57% for maintaining a predetermined deformation. Moreover, for almost constant maximum displacement, materials with a higher storage modulus absorb more impact energy and experience higher impact force as compared to materials with a lower storage modulus.

Time-dependent uniaxial piezoresistive behavior of high-density polyethylene/short carbon fiber conductive composites

2004 ◽  
Vol 19 (9) ◽  
pp. 2625-2634 ◽  
Author(s):  
Q. Zheng ◽  
J.F. Zhou ◽  
Y.H. Song
Keyword(s):  
Carbon Fiber ◽  
High Density Polyethylene ◽  
Volume Fraction ◽  
High Density ◽  
Constant Stress ◽  
Time Dependent ◽  
Short Carbon Fiber ◽  
Conductive Composites ◽  
Short Carbon ◽  
Resistance Relaxation

Short carbon fiber (SCF) filled high-density polyethylene conductive composites were studied in terms of time-dependent piezoresistive behaviors. The time-dependent change of resistance under constant stress or strain was found to be the succession of the previous pressure-dependent piezoresistance. Depending on the filler volume fraction and the level of the constant stress or strain, resistance creep and resistance relaxation with different directions were observed. An empirical expression similar to the Burgers equation could be applied to fit the data for both the resistance creep and the resistance relaxation. The fitted relaxation time as a function of pressure showed that there exist two competing processes controlling the piezoresistive behavior and its time dependence. Mechanical creep and stress relaxation of the composites were also studied, and a comparison with the time-dependent resistance implied that there is a conducting percolation network attributed to the physical contacts between SCF and a mechanical network formed by the molecular entanglement or physical crosslinking of the polymer matrix and the interaction between the filler and the matrix. It is believed that the two networks dominate the electrical and the mechanical behaviors, respectively.

High Density Polyethylene/Date Palm Fiber Composites: Effect of Fiber Loadings on the Dynamic Mechanical Thermal Properties

2018 ◽  
Vol 777 ◽  
pp. 22-26
Author(s):  
Achmad Chafidz ◽  
R.M. Faisal ◽  
Lilis Kistriyani ◽  
Ajeng Y.D. Lestari ◽  
Dhoni Hartanto ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermal Properties ◽  
Storage Modulus ◽  
High Density Polyethylene ◽  
Date Palm ◽  
High Density ◽  
Plant Fibers ◽  
Palm Fiber ◽  
Dynamic Mechanical ◽  
Logarithmic Equation

The increasing environmental issues has resulted in the trend of the use of renewable or natural source (green) fillers in the polymer composites fabrication. Among these green fillers is called natural fibers or plant fibers. One particular plant fibers that became the topic of the present work is date palm fiber (DPF). In the present work, DPF at different loadings (i.e. 0, 5, 10, 20, 30 wt%) were incorporated (as fillers) in the high density polyethylene (HDPE) matrix to fabricate HDPE/DPF composites. Further, we have investigated the effect of DPF loadings on the dynamic mechanical thermal properties of the composites. The dynamic mechanical thermal analysis (DMTA) results exhibited that the storage modulus of the composites increased with increasing DPF loadings. Additionally, all the storage modulus values of the composites were higher than the neat HDPE in all temperature ranges. For example, at temperature of 60°C, the storage modulus enhancement of the composites as compared to the neat HDPE were about 26, 76, 134, and 225% for 5, 10, 20, 30 wt% of DPF loadings, respectively. Additionally, the relationship between the DPF loadings (wt%) and temperature (°C) on the storage modulus of the HDPE/DPF composites was modeled using a logarithmic equation. Based on the data plotting between the experimental data and modeled data, the logarithmic equation was found to be fitted with the experimental data satisfactory.

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