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.

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.

scholarly journals Physical and Mechanical Properties of Ammonia-Treated Black Locust Wood

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 377 ◽  
Author(s):  
Mariana Domnica Stanciu ◽  
Daniela Sova ◽  
Adriana Savin ◽  
Nicolae Ilias ◽  
Galina A. Gorbacheva
Keyword(s):  
Mechanical Properties ◽  
Black Locust ◽  
Loss Modulus ◽  
Colour Change ◽  
Treated Wood ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Modulus Of Rupture ◽  
Elastic Behaviour ◽  
Control Samples

Because of the uneven colour of black locust wood, different technologies are used to change the colour, the bestknown being chemical and thermal treatments. Some of them affect the mechanical properties of wood, such as elasticity modulus, strength, durability. This study aims to compare the physical and mechanical properties of black locust wood control samples and treated wood samples with ammonia hydroxide, in terms of density profile, colour values (CIE L*, a*, b*), mechanical properties of samples subjected to static bending, viscous-elastic properties (storage modulus (E’), loss modulus (E”) and damping (tanδ)). Two types of ammonia-fuming treatment were applied on samples: first treatment T1-5% concentration of ammonia hydroxide for 30 days; second treatment T2-10% concentration for 60 days. The results highlighted the following aspects: the overall colour change in the case of the second treatment is 27% in comparison with 7% recorded for the control samples; the lightness and yellowness values are the most affected by the second ammonia treatment of black locust wood. The density increased with almost 20% due to ammonium fuming (10% concentration/60 days); in case of static bending, the elastic modulus (MOE) tends to decrease with increasing the exposure time to ammonium, but the modulus of rupture (MOR) increases with almost 17% and the breaking force increases too, with almost 41%. In the case of dynamic mechanical analysis, the temperature leads to different viscous-elastic behaviour of each type of samples.

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

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.

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 analysis (DMA) of waterlogged archaeological wood at room temperature

Holzforschung ◽  
2018 ◽  
Vol 72 (5) ◽  
pp. 421-431 ◽  
Author(s):  
Benedetto Pizzo ◽  
Elisa Pecoraro ◽  
Simona Lazzeri
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Room Temperature ◽  
Loss Modulus ◽  
Basic Density ◽  
Mechanical Analysis ◽  
Sustained Load ◽  
Three Point Bending ◽  
Dynamic Mechanical ◽  
Archaeological Wood ◽  
Water Saturated

AbstractThe viscoelastic properties of waterlogged wood (WLW) were investigated via dynamic mechanical analysis (DMA) at room temperature and under water saturated conditions, aiming at the investigation of the relationships between viscoelasticity and chemical composition. Different softwoods (SWs) and hardwoods (HWs) from several archaeological sites were sampled, which had different levels of decay (from highly-decayed to little changed). The analytical methods included lignin and holocellulose determination by Fourier transform infrared (FTIR) spectroscopy, moisture content (MC), basic density (BD), micromorphological observations, and the DMA was performed in three-point bending and submersion mode. Both HWs and SWs showed an exponential decrease of both storage modulus (E′) and loss modulus (E″), which are related to the amount of crystalline and paracrystalline cellulose left in the cell wall, respectively. The ratio E″/E′ (tanδ) varied with the frequency in different ways depending on the preservation state of the samples. Less decayed material had a higher tanδ than the fresh reference wood and lower (or similar) tanδ in the case of highly decayed samples. Accordingly, the long-term behaviour under a certain sustained load of WLW is decay dependent.

Dynamic-Mechanical Analysis of Polyester Composites Reinforced with Giant Bamboo (Dendrocalmus giganteus) Fiber

2014 ◽  
Vol 775-776 ◽  
pp. 302-307 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Lucas Barboza de Souza Martins ◽  
Rômulo Leite Loiola ◽  
Michel Picanço Oliveira
Keyword(s):  
Loss Modulus ◽  
Mechanical Analysis ◽  
Damping Capacity ◽  
Matrix Composites ◽  
Mechanical Parameters ◽  
Dynamic Mechanical ◽  
Polyester Matrix ◽  
Bamboo Fibers ◽  
Polyester Composites ◽  
Tan Δ

To investigate the variation with temperature of the dynamic-mechanical parameters for the polyester matrix composites incorporated with up to 30% in volume of giant bamboo fiber was the motivation of this work. The analyzed parameters were the storage modulus, the loss modulus and the delta tangent. The investigation was conducted in the temperature interval from 25 to 195°C in a DMA equipment operating at 1 Hz of frequency under a flow of nitrogen. The results showed that the incorporation of long and aligned giant bamboo fibers tends to increase the viscoelastic stiffness of the polyester matrix. By contrast, only minor changes occurred in both the glass transition temperature and the damping capacity of the structure as measured by the tan δ peaks. These are indications that the polyester molecular mobility is not sensibly affected by interaction with the bamboo fibers in the composites.

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