Accuracy in locating glass transitions: aging and gamma sterilization of vulcanized thermoplastic elastomers

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Witold Brostow ◽  
Sameer Deshpande ◽  
Dorota Pietkiewicz ◽  
Steven R. Wisner
Keyword(s):  
Loss Modulus ◽  
Accelerated Aging ◽  
Mechanical Analysis ◽  
Thermoplastic Elastomers ◽  
Rapid Decrease ◽  
Practical Reasons ◽  
Glass Transitions ◽  
Γ Irradiation ◽  
Tan Δ

AbstractWe have studied nine thermoplastic vulcanizate elastomers (TPVs) in four series: as made, after accelerated aging, after γ irradiation, after both irradiation and aging. The materials exhibit two glass transitions, one seen in crosslinked regions and the other in un-crosslinked amorphous regions. Three techniques of determination of glass transitions have been used and the results compared, all three based on dynamic mechanical analysis (DMA): as a peak in the loss modulus E’’; as a peak in tan δ; and as the midpoint of the rapid decrease in the storage modulus E’. We recommend the last method for both fundamental and practical reasons.

Dynamic Mechanical Analysis of Bio-Based and Synthetic Petroleum Based Polymer Foams with Powder Type Organic Filler at Prolonged Ultra-Violet Exposure

2020 ◽  
Vol 01 (01) ◽  
Author(s):  
M A Zulhakimie ◽  
◽  
Anika Zafiah M. Rus ◽  
N S S Sulong ◽  
A Syah Z A ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Polymer ◽  
Loss Modulus ◽  
Ultra Violet ◽  
Mechanical Analysis ◽  
Uv Exposure ◽  
Polymer Foams ◽  
Polymer Foam ◽  
Powder Filler ◽  
Tan Δ

Wood powder filler applied to the bio-based and epoxy polymer foams has the potential to reinforce the polymer foam structure. The 'Meranti' wood filler type was used as the filler in this analysis. In order to observe the pore size of each sample when exposed to different hours of UV exposure using optical microscopy (OM), this study was made.This analysis was conducted to compare the mechanical properties of each sample with different filler ratios of 0 wt%, 5 wt%, 10 wt%, 15wt% and 20 wt% at different UV exposure hours, which is 0 hour to 6000 hours with a 2000 hour rapid increase. Using the DMA Q800 TA unit, the mechanical properties were studied. In order to obtain the product of their mechanical properties, samples having a scale of 40 x 10 x 5 mm were clamped into the machine. The results will show the value of tan δ, loss modulus and storage modulus from the DMA test.The tan δ value shows that the high tanδvalue will be produced by the higher ratio filler. In contrast to bio-based polymer foams, epoxy polymer foams with powder fillers have the highest tan δ value. It shows that the higher filler ratio can be reported with the lower tan δ value. As the filler ratio filler in the polymer foams increased, the consequence of storage and loss modulus was found to increase. The greater the modulus of loss and the modulus of storage, the lower the temperature. As energy is lost as heat during UV irradiation exposure, bio-based polymer foams with a high powder filler ratio can dissipate more energy.

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.

Thermo-Mechanical Analysis of Chosen Epoxy Resins Used in Aviation Technology

2015 ◽  
Vol 1126 ◽  
pp. 187-193
Author(s):  
Kamil Prusak ◽  
Janusz Zmywaczyk ◽  
Piotr Koniorczyk ◽  
Jan Godzimirski ◽  
Marcin Cegła
Keyword(s):  
Thermal Expansion ◽  
Epoxy Resins ◽  
Loss Modulus ◽  
Testing Machine ◽  
Mechanical Analysis ◽  
Stress Strain ◽  
Temperature Range ◽  
Heating And Cooling ◽  
Tan Δ ◽  
Material Testing Machine

In this paper the results of storage modulus (E’), loss modulus (E’’) and damping parameter tan (δ)=E''/E' of epoxy resins Epidian 57 and L285 with curing agents Z1 and LH285, respectively are presented. In addition to this the stress-strain and thermal expansion characteristics of Epidian 53, 57 and L285 were obtained experimentally in order to compare Dynamic Mechanical Analysis (DMA) results. Temperature range of DMA investigations using Netzsch (Germany) DMA 242C analyzer was from-120 °C to +110 °C at the heating rate of 1 K/min with frequency of {0.1, 1, 10} Hz, respectively. Netzsch DIL 402C dilatometer was used to study the thermal expansion of the tested samples within temperature range from 30 °C to 80 °C at 1 K/min of heating and cooling rates, respectively and Huang TA computer servo control material testing machine HT-2402 was applied to determine the stress-strain characteristics. Measurements of sample elongation ΔL and physical α* were performed twice in heating and cooling cycles. The glass transition temperature Tg determined from maximum of tan (δ) curve at f = 1Hz was equal to 76.7 °C for E57 and 87.2 °C for L285. It has been observed durable deformed shape of L285 sample with deflection in the middle about 5 mm just after finishing the DMA first run of heating which significantly affected DMA results during the second run of heating

scholarly journals The Viscoelastic Behaviour of Waterlogged Archaeological Wood Treated with Methyltrimethoxysilane

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5150
Author(s):  
Magdalena Broda ◽  
Morwenna J. Spear ◽  
Simon F. Curling ◽  
Graham A. Ormondroyd
Keyword(s):  
Loss Modulus ◽  
Treated Wood ◽  
Mechanical Analysis ◽  
Viscoelastic Behaviour ◽  
Archaeological Wood ◽  
Conservation Treatment ◽  
Resistance To Deformation ◽  
Tan Δ ◽  
The One ◽  
Degree Of Degradation

Waterlogged wood treatment with methyltrimethoxysilane (MTMS) proved effective in stabilising wood dimensions upon drying (anti-shrink efficiency of 76–93%). Before the method can be proposed as a reliable conservation treatment, further research is required that includes the evaluation of the mechanical properties of treated wood. The aim of the study was to characterise the effect of the treatment on the viscoelastic behaviour of archaeological waterlogged elm and oak wood differing in the degree of degradation. Dynamic mechanical analysis in the temperature range from −150 to +150 °C was used for the study. To better understand the viscoelastic behaviour of the treated wood, pore structure and moisture properties were also investigated using Scanning Electron Microscopy, nitrogen sorption, and Dynamic Vapour Sorption. The results clearly show that methyltrimethoxysilane not only prevents collapse and distortions of the degraded cell walls and decreases wood hygroscopicity (by more than half for highly degraded wood), but also reinforces the mechanical strength by increasing stiffness and resistance to deformation for heavily degraded wood (with an increase in storage modulus). However, the MTMS also has a plasticising effect on treated wood, as observed in the increased value of loss modulus and introduction of a new tan δ peak). On the one hand, methyltrimethoxysilane reduces wood hygroscopicity that reflects in lower wood moisture content, thus limiting the plasticising effect of water on wood polymers, but on the other hand, as a polymer itself, it contributes to the viscous behaviour of the treated wood. Interestingly, the effect of silane differs with both the wood species and the degree of wood degradation.

Corrosion Protection Performance of Organic Offshore Coating Systems at −60 °C Temperature Shock

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
A. W. Momber ◽  
M. Irmer ◽  
N. Glück ◽  
P. Plagemann
Keyword(s):  
Corrosion Protection ◽  
Loss Modulus ◽  
Accelerated Aging ◽  
Mechanical Analysis ◽  
Organic Coating ◽  
Temperature Sensitive ◽  
Sensitive Coating ◽  
Protection Capability ◽  
High Storage ◽  
Very High

Six organic coating systems were investigated according to their corrosion protection performance under simulated Arctic offshore conditions. The investigations involved accelerated aging, coating adhesion measurements, and dynamic mechanical analysis (DMA). The test conditions were adapted to Arctic offshore conditions, which mainly covered temperature shocks between −20 and −60 °C, chloride exposure, dry–wet cycles, and ultraviolet (UV) radiation. Corrosion protection capability dropped for all coatings if temperature decreased from −20 °C to −60 °C. Two types of coatings could be classified according to their response to the corrosive load: temperature-sensitive coatings and insensitive coatings. Adhesive effects (interface between coating system and substrate) were found to be marginal only at low temperatures and did not affect the response of the coatings to the corrosive load. Cohesive effects (mechanical properties of free polymer films) could be identified in terms of a very high storage modulus and changes in the loss modulus for a temperature-sensitive coating at −60 °C.

Dynamic Mechanical Analysis on Regenerated Cellulose

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
Mariana Cristea ◽  
Daniela Ionita ◽  
Bogdan C. Simionescu
Keyword(s):  
Loss Modulus ◽  
Mechanical Analysis ◽  
Regenerated Cellulose ◽  
Glass Transitions ◽  
Dynamical Mechanical Analysis ◽  
Dynamic Mechanical ◽  
Two Samples ◽  
Secondary Relaxations ◽  
Shed Light

Dynamical mechanical analysis was applied to two samples of cellulose (Cell 1 and Cell 2), obtained using the N-methylmorpholine-N-oxide blown technology in order to shed light on the secondary relaxations of cellulose. By tracking the storage modulus (E�), the loss modulus (E�) and loss factor (tand) vs. temperature it becomes possible to ascertain the dynamic molecular phenomena. A multiplex experiment (0.1, 0.5, 1, 5 and 10 Hz) was performed to calculate the apparent activation energy for the sub-glass transitions. Water and peculiarities of the fabrication process influence the dynamic mechanical behaviour of cellulose. To evidence the plasticizer/antiplasticizer role of water molecules four consecutive heating-isothermal-cooling cycles were accomplished.

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 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.

Damping Properties of Novel Organic Hybrids of Textile Reclaimed Rubber and Hindered Phenol

2013 ◽  
Vol 834-836 ◽  
pp. 195-198
Author(s):  
Xiao Ou Zhou ◽  
Sheng Jiang ◽  
Xiong Yan ◽  
Xue Ting Liu ◽  
Li Li
Keyword(s):  
Storage Modulus ◽  
Hybrid Composites ◽  
Loss Modulus ◽  
Low Cost ◽  
Waste Product ◽  
Mechanical Analysis ◽  
Textile Mill ◽  
Molecular Hydrogen Bond ◽  
Hindered Phenol ◽  
Tan Δ

A series of thin, low-cost and environment-friendly organic hybrid composites consisting of reclaimed rubber (R-Rubber) which is a waste product of roller processing of textile mill filled with organic hindered phenol compound 2, 2-methylenebis (6-tert-butyl-4-methyl-phenol) (AO2246) were fabricated. In this study the damping property of the R-Rubber composites were tested in the dynamic mechanical analysis (DMA). The study concluded that R-Rubber/AO2246 composites exhibited an exceptional damping performance with a broad temperature range. Meanwhile, by addition of AO2246, the tan δ peak maximum (tan δmax) of R-Rubber/AO2246 composite was remarkably increased up to 1.5. Furthermore, with increasing the AO2246 content, storage modulus (E') and loss modulus (E") increases up to R-Rubber/AO2246 (100/80) and then becomes smaller. There is critical value on E and E" increasing which is caused by the excessive crystallization. The Interaction of AO2246 crystallizing, hybridized state and Molecular hydrogen bond led not only to control Tan δmaxof R-Rubber, but also to regulate glass transition temperature and improve the storage modulus, which make R-Rubber have potential applications in fields of engineering.

Dynamic Mechanical Properties of NR-HDPE Blends

1987 ◽  
Vol 60 (4) ◽  
pp. 591-599 ◽  
Author(s):  
S. Akhtar ◽  
S. S. Bhagawan
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Storage Modulus ◽  
Loss Tangent ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Thermoplastic Elastomers ◽  
Dynamic Mechanical ◽  
Storage And Loss Moduli ◽  
Tan Δ

Abstract Dynamic mechanical properties such as storage modulus, loss modulus, and loss tangent have been evaluated over a wide range of temperatures for thermoplastic elastomers prepared from blends of NR and HDPE. It was observed that above room temperature, both storage and loss moduli increased and loss tangent decreased as the HDPE content in the blend increased. The effects of dynamic crosslinking and carbon black filler on dynamic mechanical behavior of 70/30 NR/HDPE blend were also examined. Carbon black increased the storage and loss moduli but lowered and broadened the tan δ peak. On the other hand, crosslinking increased storage modulus and decreased the loss modulus and loss tangent, particularly after the NR Tg. The tan δ peak area which appeared at Tg for NR was proportional to the rubber content in the blends.

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