Dynamic Mechanical Analysis of Polyurethane-Epoxy Interpenetrating Polymer Networks

2009 ◽  
Vol 21 (5) ◽  
pp. 608-623 ◽  
Author(s):  
Mariana Cristea ◽  
Sorin Ibanescu ◽  
Constantin N. Cascaval ◽  
Dan Rosu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Dynamic Mechanical Analysis ◽  
Loss Factor ◽  
Loss Modulus ◽  
Polymer Networks ◽  
Mechanical Analysis ◽  
Interpenetrating Polymer Networks ◽  
Dynamic Mechanical ◽  
Tan Δ

A series of semi-interpenetrated polymer networks based on bisphenol A epoxy resin and polyurethane was synthesized by sequential procedure. The molecular dynamics of polyurethane incorporated in the resin network with increasing amounts of resin was followed by dynamic mechanical analysis. All phenomena that concur in the material are evaluated by cross-examination of the storage modulus ( E'), loss modulus ( E'') and loss factor (tan δ) variation with temperature. Complex aspects were elucidated in consecutive heating-cooling-heating cycles and by calculating the apparent activation energy of relaxations in multiplex experiments.

Effects of Palm Waste Filled Thermoplastic Composites on Dynamic Mechanical Analysis

2018 ◽  
Vol 280 ◽  
pp. 422-430
Author(s):  
M.S. Zakaria ◽  
Che Mohd Ruzaidi Ghazali ◽  
Kamarudin Hussin ◽  
Mohd Kahar A. Wahab ◽  
K.A. Abdul Halim ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Filler Loading ◽  
Thermoplastic Composites ◽  
Dynamic Mechanical ◽  
Twin Screw ◽  
Fine Size ◽  
Tan Δ ◽  
Palm Waste

The effects of palm waste (palm slag and palm ash) filled thermoplastic (high density polyethylene (HDPE) and recycled HDPE (rHDPE)) composites on dynamic mechanical analysis were examined. Two different particle size (150 μm – 300 μm) as coarse size and (≤ 75 μm) as fine size were used in this study. The palm waste of HDPE and rHDPE with 8 different types of sample were prepared using a twin screw extruder. 10 % of filler loading was chosen to produce the composite. The DMA result indicated that the fine size palm ash and coarse size palm slag have highest storage modulus incorporated with rHDPE composite meanwhile the effect of palm slag incorporated with HDPE also shown the similar findings as palm ash incorporated with HDPE. The loss modulus indicated that the coarse size of palm slag shows the lowest value and virgin HDPE gained the highest value after 90 °C in HDPE composite meanwhile fine size of palm ash and coarse size of palm slag both indicates the highest value when incorporated with rHDPE composite. For tan δ there are no significant differences recorded between the palm waste filled HDPE composite where virgin HDPE show the highest value. Meanwhile coarse size palm slag composite recorded the nearly identical tan δ value of rHDPE as the highest filled rHDPE composite. Conclusively, fine size palm ash and coarse size palm slag show the better viscoelastic properties in rHDPE composite.

Dynamic Mechanical Analysis of Nanosilica Filled Epoxy Nanocomposites

2014 ◽  
Vol 699 ◽  
pp. 239-244 ◽  
Author(s):  
Nurhidayah R. Zamani ◽  
Aidah Jumahat ◽  
Rosnadiah Bahsan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Polymer ◽  
Loss Modulus ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Dynamic Mechanical ◽  
Mechanical Stirring ◽  
Tan Δ

In this study, Dynamic Mechanical Analyzer (DMA) was used to study the effect of nanoparticles, which is nanosilica, on glass transition temperature (Tg) of epoxy polymer. A series of epoxy based nanosilica composite with 5-25 wt% nanosilica content was prepared using mechanical stirring method. The weight fractions of nanosilica in epoxy were 5 wt%, 13 wt% and 25 wt%. 30mm x 10mm x 3mm size specimens were tested using DMA machine from room temperature up to 180oC at 2°C/min heating rate. From the analysis of the results, dynamic modulus and glass transition temperature of pure polymer and nanosilica filled polymer were obtained. The glass transition of a polymer composite is a temperature-induced change in the matrix material from the glassy to the rubbery state during heating or cooling. Glass transition temperature Tg was determined using several method: storage modulus onset, loss modulus peak, and tan δ peak. The results showed that the presence of nanosilica reduced Tg of epoxy polymer.

scholarly journals Dynamic Mechanical Analysis on Delaminated Flax Fiber Reinforced Composites

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2559 ◽  
Author(s):  
Yiou Shen ◽  
Jiayi Tan ◽  
Luis Fernandes ◽  
Zehua Qu ◽  
Yan Li
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Loss Factor ◽  
Composite Laminate ◽  
Low Frequency ◽  
Mechanical Analysis ◽  
Fiber Reinforced ◽  
Dynamic Mechanical ◽  
Reinforced Composite ◽  
Local Flexibility ◽  
Low Amplitude

It is well-known that the presence of the delamination in a plant fiber-reinforced composite is difficult to detect. However, the delamination introduces a local flexibility, which changes the dynamic characteristics of the composite structure. This paper presents a new methodology for composite laminate delamination detection, which is based on dynamic mechanical analysis. A noticeable delamination-induced storage modulus reduction and loss factor enhancement have been observed when the delaminated laminate was subjected to a forced oscillation compared to the intact composite laminate. For delamination area of 12.8% of the whole area of the composite laminate, loss factor of approximately 12% increase was observed. For near-to-surface delamination position, loss factor of approximately an 18% increment was observed. The results indicate that the delamination can be reliably detected with this method, and delamination position shows greater influence on the loss factor than that of the delamination size. Further investigations on different frequencies and amplitudes configurations show that the variation of loss factor is more apparently with low frequency as well as the low amplitude.

scholarly journals Dynamic Mechanical Analysis as a Complementary Technique for Stickiness Determination in Model Whey Protein Powders

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1295
Author(s):  
Laura O’Donoghue ◽  
Md. Haque ◽  
Sean Hogan ◽  
Fathima Laffir ◽  
James O’Mahony ◽  
...  
Keyword(s):  
Glass Transition ◽  
Dynamic Mechanical Analysis ◽  
Whey Protein ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Whey Protein Concentrate ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Storage And Loss Moduli ◽  
Lower Protein

The α-relaxation temperatures (Tα), derived from the storage and loss moduli using dynamic mechanical analysis (DMA), were compared to methods for stickiness and glass transition determination for a selection of model whey protein concentrate (WPC) powders with varying protein contents. Glass transition temperatures (Tg) were determined using differential scanning calorimetry (DSC), and stickiness behavior was characterized using a fluidization technique. For the lower protein powders (WPC 20 and 35), the mechanical Tα determined from the storage modulus of the DMA (Tα onset) were in good agreement with the fluidization results, whereas for higher protein powders (WPC 50 and 65), the fluidization results compared better to the loss modulus results of the DMA (Tα peak). This study demonstrates that DMA has the potential to be a useful technique to complement stickiness characterization of dairy powders by providing an increased understanding of the mechanisms of stickiness.

Mechanical Properties of Coil Coating Evaluated with Dynamic Mechanical Analysis in Daul Cantilever

2007 ◽  
Vol 353-358 ◽  
pp. 1729-1732 ◽  
Author(s):  
Lei Chen ◽  
Hong Liang Pan
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Analysis ◽  
Loss Modulus ◽  
Paint Layer ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Mode Analysis ◽  
Dynamic Mechanical ◽  
Preparation Conditions ◽  
Coil Coating

The storage modulus, loss modulus, loss tangent (tanδ), stress and strain have been determined for painted steel specimens by dynamic mechanical analysis (DMA) operated in Dual Cantilever mode. Analysis of the composite system enabled the elastic modulus of the paint layer to be calculated and the result can be useful to analyze the mechanical properties of the coil coating. The calculation was found to be very sensitive to the geometry (especially thickness of the substrate and coating) and properties of the substrate and coating, leading to considerable variability in the calculated coating modulus. The DMA method was successful in detecting the glass transition temperature (Tg) as a peak in the tanδ curve. The value of Tg is sensitive to the preparation conditions (e.g. curing temperature) and composition of the paint. The results show that DMA in Dual Cantilever can be useful as a characterization tool for painted steel.

Dynamic Mechanical Analysis of Fly Ash Filled Polyurea Elastomer

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Jing Qiao ◽  
Alireza V. Amirkhizi ◽  
Kristin Schaaf ◽  
Sia Nemat-Nasser
Keyword(s):  
Glass Transition ◽  
Fly Ash ◽  
Dynamic Mechanical Analysis ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Dynamic Mechanical ◽  
Storage And Loss Moduli ◽  
Temperature Superposition

In this work, the material properties of a series of fly ash/polyurea composites were studied. Dynamic mechanical analysis was conducted to study the effect of the fly ash volume fraction on the composite’s mechanical properties, i.e., on the material’s frequency- and temperature-dependent storage and loss moduli. It was found that the storage and loss moduli of the composite both increase as the fly ash volume fraction is increased. The storage and loss moduli of the composites relative to those of pure polyurea initially increase significantly with temperature and then slightly decrease or stay flat, attaining peak values around the glass transition region. The glass transition temperature (measured as the temperature at the maximum value of the loss modulus) shifted toward higher temperatures as the fly ash volume fraction increased. Additionally, we present the storage and loss moduli master curves for these materials obtained through application of the time-temperature superposition on measurements taken at a series of temperatures.

Application of dynamic mechanical analysis techniques to bismuth telluride based thermoelectric materials

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Witold Brostow ◽  
Kevin P. Menard ◽  
John B. White
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Bismuth Telluride ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Tan Δ ◽  
Te Material

Abstract Dynamic mechanical analysis (DMA) techniques are commonly applied to characterize polymer-based materials - but little if at all to characterize semiconductor thermoelectric (TE) materials. TE materials may be coupled with polymeric materials in advanced thermoelectric devices, and the knowledge of TE material properties will be useful in the choice of materials for future applications. We have obtained DMA results for both n-type and p-type bismuth telluride based TE materials. We find that tan δ values, indicative of viscoelastic energy dissipation modes, approach the values for glassy or semi-crystalline polymers, and are larger by more than a whole order of magnitude than the tan δ of structural metals. DMA thermal scans show clear hysteresis-type effects and a correlation with differential scanning calorimetry thermal transitions. DMA properties as a function of frequency are briefly discussed. Our results show that DMA techniques are useful in the evaluation of thermophysical and thermomechanical properties of these TE materials and of assembled coolers. The viscoelastic effects we report may provide a damping mechanism for severe stresses inherent to service conditions of the TE coolers.

Dynamic Mechanical Analysis of Synthetic epoxy (E) and Bio-epoxy Polymer Foam Integrated with Wood Filler Under 8000 hours Exposure to UV Irradiation

2020 ◽  
Vol 01 (01) ◽  
Author(s):  
A. Alzomor ◽  
◽  
A. Z. M. Rus ◽  
H. A. Wahab ◽  
N. S. M. Salim ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Uv Irradiation ◽  
Epoxy Polymer ◽  
Mechanical Analysis ◽  
Filler Material ◽  
Polymer Foam ◽  
Dynamic Mechanical ◽  
Pu Foam ◽  
Powder Filler ◽  
Tan Δ

The most common sustainable polymer for polyurethane (PU) materials is the production of polyurethane (PU) materials using renewable resources, which will reduce thedependency on petroleum-based products for consumption.This research presents findings from an experimental research on dynamic mechanical and viscoelastic properties such as storage module (E'), loss module(E") and damping coefficient(tan δ)of synthetic epoxy (E) and bio-epoxy (B) polymer foam with different loading ratios of 0%, 5%, 10%, 15% and 20% flakes and powder filler.The samples were then exposed to 8000 hours of UV irradiation. The samples were subjected to dynamic mechanical analysis (DMA) over a temperature range of 25-180 ° C for (E) and (B) polymer foam at a frequency of 1 Hz.The results showed that the 20 %synthetic epoxy with flakes filler material, namely as E20L sample with the highest filler ratio, gives the maximum storage module and loss module values (0.3125 MPa and0.0625 MPa respectively), among other filler ratios due to bonding between foam and filler resulting in increased viscosity of the synthetic-epoxy PU foam. The bio-epoxy PU foam with a 5% powder filler material (B5P), has the highest storage value (3,956 MPa) and loss module (17,213 MPa), showing that bio-epoxy PU foams can dissipate energy faster than synthetic-epoxy polymer foams.Thermogravimetric analysis (TGA) showed that the synthetic epoxy (E) polymer foam had a higher Tg value and the highest value was reported by E5L (1.2) compared to bio-epoxy foams with far less repeatable results due to the less homogeneous polyol structure.

scholarly journals Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis

2018 ◽  
Vol 43 (3) ◽  
pp. 307-314 ◽  
Author(s):  
JEX Ong ◽  
AU Yap ◽  
JY Hong ◽  
AH Eweis ◽  
NA Yahya
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Loss Tangent ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Artificial Saliva ◽  
Mechanical Analysis ◽  
Distilled Water ◽  
Glass Ionomer ◽  
Dynamic Mechanical

SUMMARY This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10−3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

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