Dynamic Mechanical Properties of Polyethylene Melts: Calculation of Relaxation Spectrum from Loss Modulus

1971 ◽  
Vol 15 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Ramesh N. Shroff
Keyword(s):  
Mechanical Properties ◽  
Relaxation Spectrum ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Polyethylene Melts

scholarly journals Dynamic Mechanical Properties of Hybrid Layered Silicates/Kaolin Geopolymer Filler in Epoxy Composites

2017 ◽  
Vol 54 (3) ◽  
pp. 543-545 ◽  
Author(s):  
Yusrina Mat Daud ◽  
Kamarudin Hussin ◽  
Azlin Fazlina Osman ◽  
Che Mohd Ruzaidi Ghazali ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Hybrid Composites ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Layered Silicates ◽  
Epoxy Composites ◽  
Damping Factor ◽  
Dynamic Mechanical

Preparation epoxy based hybrid composites were involved kaolin geopolymer filler, organo-montmorillonite at 3phr by using high speed mechanical stirrer. A mechanical behaviour of neat epoxy, epoxy/organo-montmorillonite and its hybrid composites containing 1-8phr kaolin geopolymer filler was studied upon cyclic deformation (three-point flexion mode) as the temperature is varies. The analysis was determined by dynamic mechanical analysis (DMA) at frequency of 1.0Hz. The results then expressed in storage modulus (E�), loss modulus (E�) and damping factor (tan d) as function of temperature from 40 oC to 130oC. Overall results indicated that E�, E�� and Tg increased considerably by incorporating optimum 1phr kaolin geopolymer in epoxy organo-montmorillonite hybrid composites.

scholarly journals Influence of Thermally-Accelerated Aging on the Dynamic Mechanical Properties of HTPB Coating and Crosslinking Density-Modified Model for the Payne Effect

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 403 ◽  
Author(s):  
Yongqiang Du ◽  
Jian Zheng ◽  
Guibo Yu
Keyword(s):  
Mechanical Properties ◽  
Aging Time ◽  
Loss Modulus ◽  
Accelerated Aging ◽  
Crosslinking Density ◽  
Dynamic Mechanical Properties ◽  
Maximum Elongation ◽  
Solid Rocket Motor ◽  
Payne Effect ◽  
Dynamic Mechanical

Hydroxyl terminated polybutadiene (HTPB) coating is widely used in a solid rocket motor, but an aging phenomenon exists during long-term storage, which causes irreversible damage to the performance of this HTPB coating. In order to study the effect of aging on the dynamic mechanical properties of the HTPB coating, the thermally-accelerated aging test was carried out. The variation of maximum elongation and crosslinking density with aging time was obtained, and a good linear relationship between maximum elongation and crosslinking density was found by correlation analysis. The changing regularity of dynamic mechanical properties with aging time was analyzed. It was found that with the increase of aging time, Tg of HTPB coating increased, Tα, tan β and tan α decreased, and the functional relationships between the loss factor parameters and crosslinking density were constructed. The storage modulus and loss modulus of HTPB coating increased with the increase of aging time, and decreased with the increase of pre-strain. The aging enhanced the Payne effect of HTPB coating, while the pre-strain had a weakening effect. In view of the Payne effect of HTPB coating, the crosslinking density was introduced into Kraus model as aging evaluation parameter, and the crosslinking density modified models with and without pre-strain were established. The proposed models can effectively solve the problem that the Kraus model has a poor fitting effect under the condition of small strain (generally less than 1%) and on the loss modulus, which have improved the correlations between the fitting results and the test results.

Thermal stability and dynamic mechanical behavior of functional multiphase boride ceramics/epoxy composites

2019 ◽  
Vol 39 (6) ◽  
pp. 508-514
Author(s):  
Yannan He ◽  
Zhiqiang Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Element Analysis ◽  
Reaction Heat ◽  
Dynamic Mechanical

Abstract The thermal and dynamic mechanical properties of epoxy composites filled with zirconium diboride/nano-alumina (ZrB2/Al2O3) multiphase particles were investigated by means of differential scanning calorimetry, dynamic thermo-mechanical analysis, and numerical simulation. ZrB2/Al2O3 particles were surface organic functional modified by γ-glycidoxypropyltrimethoxysilane for the improvement of their dispersity in epoxy matrix. The results indicated that the curing exotherm of epoxy resin decreased significantly due to the addition of ZrB2/Al2O3 multiphase particles. In comparison to the composites filled with unmodified particles, the modified multiphase particles made the corresponding filling composites exhibit lower curing reaction heat, lower loss modulus, and higher storage modulus. Generally speaking, the composites filled with 5 wt% modified multiphase particles presented the best thermal stability and thermo-mechanical properties due to the better filler-matrix interfacial compatibility and the uniform dispersity of modified particles. Finite element analysis also suggested that the introduction of modified ZrB2/Al2O3 multiphase particles increased the stiffness of the corresponding composites.

PLA-coated sisal fibre-reinforced polyester composite: Water absorption, static and dynamic mechanical properties

2018 ◽  
Vol 53 (1) ◽  
pp. 65-72 ◽  
Author(s):  
MK Gupta ◽  
Rohit Singh
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Loss Modulus ◽  
Alkali Treatment ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Static Properties ◽  
Physical Treatment ◽  
Sisal Fibre ◽  
Dynamic Mechanical

In the present work, a novel physical treatment (PLA coating) of sisal fibres and its influence on the water absorption, static and dynamic mechanical properties of its composites has been presented. The treated sisal fibres were used consisted of alkali treatment and PLA coating to fabricate its polyester-based composites by hand lay-up technique keeping constant fibres content as 20 wt.% . Water absorption analysis was carried out in terms of water uptake (%), and sorption, diffusion and permeability coefficient. In addition, static properties were examined in terms of tensile, flexural and impact test, and dynamic mechanical analysis was performed in terms of storage modulus [Formula: see text], loss modulus [Formula: see text], damping [Formula: see text] and glass transition temperature [Formula: see text]. It was reported that the PLA-coated sisal composites showed the best performance in water absorption, mechanical and dynamic mechanical properties than pure sisal and alkali-treated sisal composites. There were 33%, 49%, 48%, and 27% improvement in water resistance, tensile strength, flexural strength and impact strength, respectively, of PLA-coated sisal composites as compared to that of pure sisal composite.

scholarly journals Effect of Short Fiber Reinforcement on Mechanical Properties of Hybrid Phenolic Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sembian Manoharan ◽  
Bhimappa Suresha ◽  
Govindarajulu Ramadoss ◽  
Basavaraj Bharath
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Loss Modulus ◽  
Basalt Fiber ◽  
Barium Sulphate ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
X Ray ◽  
Weight Percentage ◽  
Dynamic Mechanical

Fiber plays an important role in determining the hardness, strength, and dynamic mechanical properties of composite material. In the present work, enhancement of viscoelastic behaviour of hybrid phenolic composites has been synergistically investigated. Five different phenolic composites, namely, C1, C2, C3, C4, and C5, were fabricated by varying the weight percentage of basalt and aramid fiber, namely, 25, 20, 15, 10, and 5% by compensating with barium sulphate (BaSO4) to keep the combined reinforcement concentration at 25 wt%. Hardness was measured to examine the resistance of composites to indentation. The hardness of phenolic composites increased from 72.2 to 85.2 with increase in basalt fiber loading. Composite C1 (25 wt% fiber) is 1.2 times harder than composite C5. Compression test was conducted to find out compressive strength of phenolic composites and compressive strength increased with increase in fiber content. Dynamic mechanical analysis (DMA) was carried out to assess the temperature dependence mechanical properties in terms of storage modulus (E′), loss modulus (E′′), and damping factor (tan δ). The results indicate great improvement of E′ values and decrease in damping behaviour of composite upon fiber addition. Further X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were employed to characterize the friction composites.

Correlation of Microstructural Evolution With the Dynamic-Mechanical Viscoelastic Properties of Underfill Under Sustained High Temperature Operation

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Madhu Kasturi ◽  
Haotian Wu ◽  
Ed Davis ◽  
Jeff Suhling
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Optical Microscope ◽  
Dynamic Mechanical Properties ◽  
Isothermal Exposure ◽  
Dynamic Mechanical ◽  
Fine Pitch ◽  
Long Time

Abstract Automotive underhood electronics are subjected to high operating temperatures in the neighborhood of 150 to 200°C for prolonged periods in the neighborhood of 10-years. Consumer grade off-the shelf electronics are designed to operate at 55 to 85 °C with a lower use-life of 3 to 5 years. Underfill materials are used to provide supplemental restraint to fine-pitch area array electronics and meet the reliability requirements. In this paper, a number of different underfill materials are subjected to automotive underhood temperatures to study the effect of long time isothermal exposure on microstructure and dynamic-mechanical properties. It has been shown that isothermal aging oxidizes the underfill, which can change the mechanical properties of the material significantly. The oxidation of underfill was studied experimentally by measuring oxidation layer thickness using polarized optical microscope. The effect on the mechanical properties was studied using the dynamic mechanical properties of underfill with DMA (Dynamic Mechanical Analyzer). Two different underfill materials were subjected to three different isothermal exposure, which are below, near and above the glass transition temperature of the underfills. The dynamic mechanical viscoelastic properties like storage modulus, loss modulus, tan delta and their respective glass transition temperatures were investigated. Three point bending mode was used in the DMA with a frequency of 1 Hz operating at 3 °C/min.

Dynamic Mechanical Properties of MWNTs/Phenolic Nanocomposites

2006 ◽  
Vol 306-308 ◽  
pp. 1073-1078 ◽  
Author(s):  
Meng Kao Yeh ◽  
Nyan Hwa Tai ◽  
Jia Hau Liu
Keyword(s):  
Mechanical Properties ◽  
Transition Temperature ◽  
Phenolic Resin ◽  
Loss Modulus ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Tensile Failure ◽  
Dynamic Mechanical ◽  
Multi Walled Carbon Nanotube ◽  
The Difference

Two different types of multi-walled carbon nanotube (MWNT), the dispersed and the network MWNTs, were used to reinforce the phenolic resin. The MWNTs/phenolic nanocomposites were tested by a dynamic mechanical analyzer (DMA) to characterize their dynamic mechanical properties. The results showed that increasing the MWNT content can increase the storage modulus, the loss modulus and the glassy transition temperature of the MWNTs/phenolic nanocomposites. A subambient loss transition is seen in the nanocomposites with network MWNTs which results in a better impact resistance property in the nanocomposites. The glassy transition temperature of the nanocomposites with network MWNTs is higher than that of nanocomposites with dispersed MWNTs. The MWNT additive in phenolic resin can be used to improve the dynamic mechanical properties of the MWNTs/phenolic nanocomposites. The tensile failure morphologies of MWNTs/phenolic nanocomposites were also examined using field emission scanning electron microscope (FESEM) to explain the difference between the two types of nanocomposites.

Study on Dynamic Mechanical Properties of n-HA/PA66 Composites

2011 ◽  
Vol 418-420 ◽  
pp. 1511-1515
Author(s):  
Lin Cheng ◽  
Xiang Zhang ◽  
Yu Bao Li
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Physiological Saline ◽  
Dynamic Mechanical Properties ◽  
Intrinsic Properties ◽  
Polyamide 66 ◽  
Dynamic Mechanical ◽  
Reinforcing Effects

The dynamic mechanical properties of nano-hydroxyapatite (n-HA) reinforced polyamide 66 (PA66) biocomposites were studied with reference to the effect of n-HA content, frequency and physiological saline. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases determine the dynamic mechanical properties of the composite. The storage modulus (E') values of n-HA/PA66 composites were much higher than those of pure PA66, indicating that the incorporation of n-HA in PA66 matrix induced reinforcing effects obviously. And the E' values of composites increased with increasing of n-HA content. The loss modulus (E") of the composite with 30wt% n-HA was higher that those of pure PA66 and the composite with 40wt% n-HA below 55°C, however, above 55°C, the E" values enhanced with increase of n-HA content. Both frequency and physiological saline had obvious effects on the dynamic mechanical properties for n-HA/PA66 composite. E' and E" values enhanced with increase of frequency, but tanδ values decreased with increasing of frequency. After soaked in physiological saline, the E' and E" values of the composite decreased.

scholarly journals Enhancement of Mechanical and Dynamic Mechanical Properties of Hydrophilic Nanoclay Reinforced Polylactic Acid/Polycaprolactone/Oil Palm Mesocarp Fiber Hybrid Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Oil Palm ◽  
Hybrid Composites ◽  
Loss Modulus ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Dynamic Mechanical ◽  
The Fourier Transform

In previous studies, the effect of the addition of 1 wt% hydrophilic nanoclay on polylactic acid (PLA)/polycaprolactone (PCL)/oil palm mesocarp fiber (OPMF) biocomposites was investigated by tensile properties, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The current studies focus on the effect of addition of 1 wt% hydrophilic nanoclay on mechanical (flexural and impact properties) and dynamic mechanical properties of composites. The composites were characterized by the Fourier transform infrared spectroscopy (FTIR) and dynamic mechanical analysis (DMA). FTIR spectra show that peak shifting occurs when 1 wt% hydrophilic nanoclay was added to composites. The addition of 1 wt% hydrophilic nanoclay successfully improves the flexural properties and impact resistance of the biocomposites. The storage modulus of biocomposites was decreased when nanoclay was added which indicates that the stiffness of biocomposites was reduced. The loss modulus curve shows that the addition of nanoclay shift twotgin composites become closer to each other which indicates that the incorporation of nanoclay slightly compatibilizes the biocomposites. Tanδindicated that hybrid composites dissipate less energy compared to biocomposites indicate that addition of clay to biocomposites improves fiber/matrix adhesion. Water sorption test shows that the addition of nanoclay enhances water resistance of composites.

scholarly journals Dynamic mechanical analysis of nylon 6 fiber-reinforced acrylonitrile butadiene rubber composites

2021 ◽  
pp. 096739112110461
Author(s):  
C Rajesh ◽  
P Divia ◽  
S Dinooplal ◽  
G Unnikrishnan ◽  
E Purushothaman
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
Butadiene Rubber ◽  
Bonding Agents ◽  
Fiber Loading ◽  
Dynamic Mechanical ◽  
Acrylonitrile Butadiene Rubber

Dynamic mechanical properties of polymeric materials are of direct relevance to a range of unique polymer applications. The aim of the study is to investigate the dynamic mechanical properties of composites of short nylon 6 fiber with acrylonitrile butadiene rubber (NBR). The storage modulus (G′), loss modulus (G″), and the damping factor (tan δ) have been analyzed with reference to the effects of fiber loading, curing systems, and bonding agents over a range of temperature and at varying frequencies. The storage modulus increases with increment in fiber loading, whereas loss modulus and damping factor decrease. The glass transition temperature shifts to higher temperature upon increment in fiber loading. Dicumyl peroxide (DCP)–cured composites show higher storage modulus and lower damping than the corresponding sulfur-cured one. The addition of hexa-resorcinol and phthalic anhydride as bonding agents enhances the dynamic mechanical properties of the composites. The experimental results have been evaluated by comparing with Einstein, Guth, and Nielsen models.

Sign in / Sign up

Export Citation Format

Share Document