Quasi-static and dynamic nanoindentation to determine the influence of thermal treatment on the mechanical properties of bamboo cell walls

Holzforschung ◽  
2015 ◽  
Vol 69 (7) ◽  
pp. 909-914 ◽  
Author(s):  
Yanjun Li ◽  
Liping Yin ◽  
Chengjian Huang ◽  
Yujie Meng ◽  
Feng Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Thermal Treatment ◽  
Cell Walls ◽  
Loss Modulus ◽  
Treatment Temperature ◽  
Dry Density ◽  
Bamboo Fibers ◽  
Tan Δ ◽  
Dynamic Nanoindentation

Abstract Bamboo was thermally treated at 180°C and 200°C, and the micromechanical properties of its cell walls were investigated by means of quasi-static and dynamic nanoindentation experiments. With increasing treatment temperatures, the average dry density and mass of the bamboo decreased, whereas the already reduced elastic modulus at 180°C of the fiber cell walls did not change, but the hardness showed increasing tendencies. Dynamic nanoindentation revealed reduced storage modulus $({E'_{\rm{r}}})$ and loss modulus $({E''_{\rm{r}}}\,)$ for the thermotreated bamboo cell walls compared with the untreated bamboo fibers in all frequency regions. Moreover, ${E'_{\rm{r}}},{\rm{ }}{E''_{\rm{r}}},$ and loss tangent (tan δ) of treated bamboo decreased with increasing treatment temperature.

Dynamic nanomechanical response of nacre

2006 ◽  
Vol 21 (8) ◽  
pp. 2045-2051 ◽  
Author(s):  
Bedabibhas Mohanty ◽  
Kalpana S. Katti ◽  
Dinesh R. Katti ◽  
Devendra Verma
Keyword(s):  
Mechanical Properties ◽  
Loss Factor ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Spectroscopic Studies ◽  
Increase With Increase ◽  
Nanocomposite System ◽  
Brick And Mortar ◽  
Tan Δ ◽  
Dynamic Nanoindentation

Nacre, the shiny inner layer of mollusk shells is a model biomimetic nanocomposite system. Its exceptional mechanical properties have been the inspiration for materials scientists for several decades. Nacre exhibits a layered brick and mortar structure. It is composed of 95% inorganic (aragonitic CaCO3) phase and 5% organic (mainly proteins and polysaccharides) phase that are arranged in interlocked brick and mortar architecture with the mineral as bricks and organics as the mortar. In the current work, we describe the dynamic nanomechanical behavior of nacre using dynamic nanoindentation (nano-DMA) experiments. Two sets of loads were applied to obtain the dynamic response from varying depths in nacre. These tests were performed at three different frequencies (25, 50, and 100 Hz) to study the effect of frequency on the dynamic properties of nacre. The loss modulus (E″) and the loss factor (tan δ) were measured. Both of these parameters were observed to increase with increase in depth. Significant increase in tan δ was observed with the increase in frequency. Photoacoustic Fourier transform infrared spectroscopic studies on nacre indicate the presence of water in nacre. This water may be present at nanograin interfaces in nacre platelets, at organic–inorganic interfaces, and also in the organic phase in nacre. We believe that water is one of the significant contributors to the viscoelasticity of nacre. Our results indicate that the aragonite platelets in nacre may also contribute to viscoelasticity.

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 Use of waste materials in rubber matrix

2018 ◽  
Vol 157 ◽  
pp. 07009 ◽  
Author(s):  
Mariana Pajtášová ◽  
Zuzana Mičicová ◽  
Darina Ondrušová ◽  
Slavomíra Božeková ◽  
Róbert Janík ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Loss Modulus ◽  
Rolling Resistance ◽  
Dynamic Mechanical Properties ◽  
Waste Materials ◽  
Partial Replacement ◽  
Rubber Matrix ◽  
Loss Angle ◽  
Rubber Compounds ◽  
Tan Δ

The presented paper deals with the use of waste materials as ecological fillers into rubber matrix. Waste materials were used as partial replacement of the commercial filler – carbon black, designated as N339. These prepared rubber compounds were characterized on the basis of the rheology and vulcanization characteristics – minimum torque (ML), maximum torque (MH), optimum time of vulcanization (t(c90)), processing safety of compound (ts), rate coefficient of vulcanization (Rv). In the case of the prepared vulcanizates, physical-mechanical properties (tensile strength, tensibility and hardness) and dynamic-mechanical properties (storage modulus, loss modulus, loss angle tan δ) were investigated. Using the dependency of loss angle on temperature, the selected properties for tyre tread vulcanizates were evaluated, including traction on snow and ice, traction on the wet surface and rolling resistance.

scholarly journals Chemical and Mechanical Properties of Experimental Dental Composites as a Function of Formulation and Postcuring Thermal Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Renata A. Esteves ◽  
Letícia C. C. Boaro ◽  
Flávia Gonçalves ◽  
Luiza M. P. Campos ◽  
Cecy M. Silva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Thermal Treatment ◽  
Flexural Strength ◽  
Low Cost ◽  
Chemical Properties ◽  
Degree Of Conversion ◽  
Dental Composites ◽  
Molar Ratios

This study evaluated the influence of formulation and thermal treatment on the degree of conversion, fracture toughness, flexural strength, and elastic modulus of experimental composites. Six composites were analyzed at BisGMA : TEGDMA molar ratios of 1 : 1 and 7 : 3 with filler at 30, 50, and 70 wt%. The degree of conversion was analyzed by Fourier transform infrared spectroscopy, fracture toughness was measured using the single-edge notched beam, and flexural strength and elastic modulus were measured with the 3-point bend test. For all tests, one-half of the specimens received thermal treatment at 170°C for 10 min. Data were analyzed by the Kruskal-Wallis or ANOVA/Tukey’s test (α = 5%). The 1 : 1 BisGMA : TEGDMA ratio showed higher properties than the 7 : 3 ratio. Although the material with 70% filler had a conversion lower than the one with 50%, it showed higher mechanical properties. The thermal treatment improved all properties in all materials. Therefore, the use of an equimolar ratio of BisGMA : TEGDMA can be paired with 70 wt% filler to design dental composites that possess increased advantageous physical and chemical properties. Furthermore, the simple and low-cost method of thermal treatment proposed for use in clinical dentistry has been shown to effectively improve the properties of all evaluated materials.

Mechanical properties of nylon 6-clay hybrid

1993 ◽  
Vol 8 (5) ◽  
pp. 1185-1189 ◽  
Author(s):  
Yoshitsugu Kojima ◽  
Arimitsu Usuki ◽  
Masaya Kawasumi ◽  
Akane Okada ◽  
Yoshiaki Fukushima ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Loss Modulus ◽  
Nylon 6 ◽  
Heat Distortion Temperature ◽  
Molecular Composites ◽  
Silicate Layers

Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCH's and NCHP's, respectively, have been synthesized. To estimate the mechanical properties of these hybrids, tensile, flexural, impact, and heat distortion tests were carried out. NCH was found superior in strength and modulus and comparable in impact strength to nylon 6. The heat distortion temperature (HDT) of NCH (montmorillonite: 4.7 wt. %) was 152 °C, which was 87 °C higher than that of nylon 6. In NCHP, saponite had a smaller effect on the increase of these mechanical properties. The modulus and HDT of NCH and NCHP increased with an increase in the amount of clay minerals. It was found that these properties were well described by the contribution of the constrained region calculated from the storage and loss modulus at the glass transition temperature. According to the mixing law on elastic modulus, the following expression was obtained between the modulus E at 120 °C and the fraction of the constrained region C, En = Ecn = C, where the values of n and Ec (modulus of the constrained region) were 0.685 and 1.02 GPa, respectively.

scholarly journals Effects of Silicon and Heat-Treatment on Microstructure and Mechanical Properties of Biomedical Ti-39Nb-6Zr Alloy

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Ji-Hoon Jang ◽  
Dong-Geun Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Elastic Modulus ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Shielding Effect ◽  
Microstructure And Mechanical Properties ◽  
Tissue Reactions

The cytotoxic tissue reactions of alloying elements (Al, V) of Ti-6Al-4V have been reported, whereas the Ti-39Nb-6Zr (TNZ40) alloy developed by adding β-phase stabilizing elements is known to have no cytotoxicity and exhibits excellent biocompatibility. In addition, there is a slight modulus difference between the TNZ40 alloy and human bones as the elastic modulus of the TNZ40 alloy is very low. This can inhibit detrimental effects such as osteoblast loss due to a stress-shielding effect. In this study, various Si contents were added and heat treatment under various conditions was performed to control the microstructure and mechanical properties of the TNZ40 alloy. In the β-type titanium alloy, the ω phase is commonly observed by quenching from the solution-treatment or aging-treatment temperature. These ω precipitates can typically increase the elastic modulus, hardness, and embrittlement of the β-type titanium alloy, which are important to control this phase. The correlation between Si content and precipitation and the effects of solution treatment and aging condition on the mechanical properties such as tensile strength, and hardness, were analyzed.

scholarly journals INFLUENCE OF COMMERCIAL THERMAL TREATMENT ON Eucalyptus grandis Hill ex Maiden WOOD PROPERTIES

2021 ◽  
Vol 45 ◽  
Author(s):  
Carolina Aparecida Barros Oliveira ◽  
Karina Aparecida de Oliveira ◽  
Julio Cesar Molina ◽  
Vinicius Borges de Moura Aquino ◽  
André Luis Christoforo
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Treatment ◽  
Eucalyptus Grandis ◽  
Treated Wood ◽  
Wood Properties ◽  
Treatment Temperature ◽  
Saturated Steam ◽  
Physical Chemical ◽  
Different Temperatures

ABSTRACT This study aimed to evaluate the influence of commercial thermal treatment on Eucalyptus grandis considering its physical, chemical, and mechanical properties. The wood samples were heat-treated in an autoclave with saturated steam and pressure application at four different temperatures: 155, 165, 175, and 185 ºC. The physical, chemical, and mechanical properties were altered due to the heat treatment. The extractives content varied between 6.06% and 28.75%; lignin between 28.93% and 37.96%; holocellulose between 65.01% and 38.12%. The mechanical properties reduced significantly with the increase of the heat treatment temperature. Through the set of data obtained, it was possible to generate significant and high precision regression models capable of estimating such properties for heat treatment temperatures not studied experimentally, enabling the determination of the most suitable temperature of heat treatment to achieve a certain property value of the treated wood.

scholarly journals Mechanical properties and water resistance of Vietnamese acacia and rubberwood after thermo-hygro-mechanical modification

2020 ◽  
Vol 78 (5) ◽  
pp. 841-848
Author(s):  
Rulong Cao ◽  
Juhani Marttila ◽  
Veikko Möttönen ◽  
Henrik Heräjärvi ◽  
Pekka Ritvanen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Treatment ◽  
Compression Strength ◽  
Mechanical Performance ◽  
Brinell Hardness ◽  
Water Immersion ◽  
Dry Density ◽  
Fast Growing ◽  
Subsequent Thermal Treatment ◽  
Reference Specimens

Abstract Low density and poor mechanical performance often limit utilisation of sawn wood from fast-growing plantation forests. Thermo-hygro-mechanical modification (THM) of timber is one innovation for improving the properties of light-weight wood species. The objective of this study was to determine the effects of THM and subsequent thermal treatment on dry density, modulus of elasticity (MOE), compression strength, Brinell hardness, and swelling behaviour in immersion tests on two fast-growing Vietnamese species, acacia (Acacia mangium) and rubberwood (Hevea brasiliensis). Test boards were modified in an industrial kiln, in which a tangential thickness compression of 14% and 12% were aimed for acacia and rubberwood, respectively, either with or without subsequent thermal treatment at 210 °C. Dry density, MOE, Brinell hardness, compression strength, and dimensional changes in water immersion tests of specimens were measured from the modified and unmodified reference materials, the latter ones being kiln dried at 50 °C. The results showed that the responses of the mechanical properties were more evident for rubberwood than for acacia. In rubberwood, the MOE and compression strength of wood thermo-hygro-mechanically modified with or without thermal treatment were higher than those of kiln-dried reference specimens throughout the thickness profile. In case of acacia, similar differences between the modified and reference specimens were observed only in the surface layer. Density and Brinell hardness of thermo-hygro-mechanically modified rubberwood were higher than those of reference specimens, but after thermal treatment they did not differ from (acacia) or were lower (rubberwood) than those of THM specimens. Post-compression thermal treatment increased the hydrophobicity of THM specimens.

EFFECTS OF 4,4′-BISMALEIMIDODIPHENYLMETHANE CURING AGENT ON MORPHOLOGICAL, RHEOLOGICAL, AND MECHANICAL PROPERTIES OF DYNAMICALLY VULCANIZED BIIR/POLYPROPYLENE ELASTOMERS

2018 ◽  
Vol 92 (2) ◽  
pp. 298-309 ◽  
Author(s):  
Fang Wang ◽  
Aiming Zhang ◽  
Tao Zhou
Keyword(s):  
Mechanical Properties ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Continuous Phase ◽  
Curing Agent ◽  
Capillary Rheometer ◽  
Dynamic Vulcanization ◽  
Opposite Trend ◽  
Tan Δ ◽  
Pp Blends

ABSTRACT The morphological, rheological, and mechanical properties of BIIR/polypropylene (PP) blends with various amounts of 4,4′-bismaleimidodiphenylmethane (BMI) curing agent were studied. As the level of BMI curing agent increased, the rubber single particle size decreased, but the interaction among the particles strengthened to form aggregates. The rheological properties were determined with a high-pressure capillary rheometer and a rotational rheometer. It was found that the rheological behavior was affected by both the BMI content and the morphology of the blends. The increased BMI content led to the smaller vulcanized BIIR rubber particles dispersing in the PP continuous phase because of the improvement in cross-linking speed and degree as well as the viscosity of BIIR. The dynamic vulcanization strongly improved the elasticity of the blends. The storage modulus, loss modulus, and complex viscosity of cured BIIR/PP blends were all obviously higher than those of the uncured blend, whereas the values of tan δ showed the opposite trend. The as-prepared BIIR/PP thermoplastic vulcanizate exhibited suitable hardness and good mechanical properties.

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.

Sign in / Sign up

Export Citation Format

Share Document