scholarly journals Coir Fibers Treated with Henna as a Potential Reinforcing Filler in the Synthesis of Polyurethane Composites

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1128
Author(s):  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Agnė Kairytė
Keyword(s):  
Mechanical Properties ◽  
High Energy ◽  
Dynamic Mechanical Properties ◽  
Milling Process ◽  
Coir Fiber ◽  
Lawsonia Inermis ◽  
Coir Fibers ◽  
Mechanical Performances ◽  
The Impact ◽  
Reinforcing Filler

In this study, coir fibers were successfully modified with henna (derived from the Lawsonia inermis plant) using a high-energy ball-milling process. In the next step, such developed filler was used as a reinforcing filler in the production of rigid polyurethane (PUR) foams. The impact of 1, 2, and 5 wt % of coir-fiber filler on structural and physico-mechanical properties was evaluated. Among all modified series of PUR composites, the greatest improvement in physico-mechanical performances was observed for PUR composites reinforced with 1 wt % of the coir-fiber filler. For example, on the addition of 1 wt % of coir-fiber filler, the compression strength was improved by 23%, while the flexural strength increased by 9%. Similar dependence was observed in the case of dynamic-mechanical properties—on the addition of 1 wt % of the filler, the value of glass transition temperature increased from 149 °C to 178 °C, while the value of storage modulus increased by ~80%. It was found that PUR composites reinforced with coir-fiber filler were characterized by better mechanical performances after the UV-aging.

scholarly journals Casein/Apricot Filler in the Production of Flame-Retardant Polyurethane Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3620
Author(s):  
Sylwia Członka ◽  
Agnė Kairytė ◽  
Karolina Miedzińska ◽  
Anna Strąkowska
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Dynamic Mechanical Properties ◽  
Uniform Structure ◽  
Thermal And Mechanical Properties ◽  
Mechanical Performances ◽  
Polyurethane Composites ◽  
Natural Combination ◽  
The Impact ◽  
And Storage

Polyurethane (PUR) composites reinforced with 1, 2, and 5 wt.% of apricot filler modified with casein were synthesized in the following study. The impact of 1, 2, and 5 wt.% of casein/apricot filler on the cellular structure and physico-mechanical performances of reinforced PUR composites were determined. It was found that the incorporation of 1 and 2 wt.% of casein/apricot filler resulted in the production of PUR composites with improved selected physical, thermal, and mechanical properties, while the addition of 5 wt.% of casein/apricot filler led to some deterioration of their physico-mechanical performance. The best results were obtained for PUR composites reinforced with 2 wt.% of casein/apricot filler. Those composites were characterized by a uniform structure and a high content of closed cells. Compared with the reference foam, the incorporation of 2 wt.% of casein/apricot filler resulted in improvement in compressive strength, flexural strength, impact strength, and dynamic mechanical properties—such as glass transition temperature and storage modulus. Most importantly, PUR composites showed better fire resistance and thermal stability due to the good thermal performance of casein. The main aim of this article is to determine the influence of the natural combination of the apricot filler and casein on the mechanical properties and flammability of the obtained composites.

Characterization and Utilization of Coconut Fibers of the Caribbean

2014 ◽  
Vol 1611 ◽  
pp. 95-104 ◽  
Author(s):  
Nadira Mathura ◽  
Duncan Cree ◽  
Ryan P. Mulligan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Micrographs ◽  
Saline Water ◽  
Gauge Length ◽  
Scanning Electron Micrographs ◽  
Coir Fiber ◽  
Coir Fibers ◽  
The Caribbean ◽  
Scanning Electron

ABSTRACTIn many tropical countries coconut (coir) fiber production is a major source of income for rural communities. The Caribbean has an abundance of coconuts but research into utilizing its by-products is limited. Environmentally friendly coir fibers are natural polymers generally discarded as waste material in this region. Research has shown that coir fiber from other parts of the world has successfully been recycled. This paper therefore investigates the mechanical properties of Caribbean coir fiber for potential applications in civil engineering.Approximately four hundred fibers were randomly taken from a coir fiber stack and subjected to retting in both distilled and saline water media. The mechanical properties of both the retted and unretted coir fibers were evaluated at weekly increments for a period of 3 months. Tensile strength test, x-ray diffraction analysis and scanning electron micrographs were used to assess trends and relationships between fiber gauge lengths, diameter, tensile strength and Young’s modulus. Diameters ranged between 0.11 mm-0.46 mm, while fiber samples were no longer than 250 mm in length. The tensile strength and strain at break decreased as the gauge length increased for both unretted and retted fibers. The opposite occurred for the relationship between the gauge length and Young’s modulus. Additionally, the tensile strength and modulus decreased as the fiber diameter increased. Neither distilled nor saline water improved the coir fiber’s crystalline index. Scanning electron micrographs qualitatively assessed fiber surfaces and captured necking and microfibril degradation at the fractured ends.The analysis revealed that the tensile strength, modulus, strain at break and crystallinity properties of the Caribbean coir fibers were comparable to commercially available coir fiber which are currently being used in many building applications.

Characteristics Analysis of Coir Fiber and Performance Evaluation of Coir Fiberboard

2010 ◽  
Vol 146-147 ◽  
pp. 1549-1552
Author(s):  
Jia Yao ◽  
Ying Cheng Hu ◽  
Wei Lu ◽  
Jin Li
Keyword(s):  
Mechanical Properties ◽  
Nondestructive Testing ◽  
Orthogonal Experiment ◽  
Surface Characteristics ◽  
Dynamic Mechanical Properties ◽  
National Standards ◽  
Coir Fiber ◽  
Static Test ◽  
Characteristics Analysis ◽  
And Performance

SEM observations of coir fiber microstructure have been carried out. Uneven surface characteristics are conducive to the bonding between coir fibers and resin materials. The unique advantages of coir fiber have been verified. Doing orthogonal experiment design for coir fiberboard, the coir fiberboard can meet the mechanical properties of National Standards of China. The various factors optimization plan on the performance of coir fiberboard has been obtained. FFT nondestructive testing has been done for the coir fiberboard. Nondestructive testing results show that the good correlation exists between dynamic mechanical properties and the static test results.

scholarly journals Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2105 ◽  
Author(s):  
Alon Ratner ◽  
Richard Beaumont ◽  
Iain Masters
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Lithium Ion ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Impact Testing ◽  
Significant Feature ◽  
Dynamic Mechanical ◽  
The Impact

Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.

scholarly journals Dynamic Fracture Experiment of Fractured Rock under Dynamic Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-22
Author(s):  
Yanbing Wang ◽  
Xingyuan Zhou ◽  
Ji Kong ◽  
Bingbing Yu
Keyword(s):  
Mechanical Properties ◽  
Energy Loss ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Fractured Rock ◽  
Dynamic Mechanical Properties ◽  
Dynamic Crack ◽  
Loading Test ◽  
Dynamic Mechanical ◽  
The Impact

In order to examine the dynamic mechanical properties, dynamic crack proposition process, and energy loss of fractured rock under dynamic loading, the specimens with different fracture dig angles were processed with Φ50 mm × 50 mm cylindrical sandstone, the impact loading test was conducted on 50 mm stem diameter split Hopkinson pressure bar (SHPB) experiment platform, and the whole process of crack propagation and dynamic failure was recorded using a high-speed camera. As a result, the dynamic mechanical properties such as stress wave fluctuation characteristics, peak strength and stress-strain relationship, crack initiation angle, stress and other dependencies with prefabricated fracture angle of the prefabricated fracture specimens under high strain rate were obtained, and the incident energy, absorbed energy, and energy absorption rates were compared to investigate the energy loss law in the dynamic loading; on the contrary, the effects of different loading rates on the dynamic mechanical properties of the sandstone specimens were identified, and finally a set of findings were presented.

scholarly journals Influence of Cyclic Impact Loading and Axial Stress on Dynamic Mechanical Properties of Burst-Prone Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-10 ◽  
Author(s):  
Shuang Gong ◽  
Zhen Wang ◽  
Lei Zhou ◽  
Wen Wang
Keyword(s):  
Mechanical Properties ◽  
Impact Loading ◽  
Coal Sample ◽  
Impact Load ◽  
Axial Stress ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Cyclic Impact Loading ◽  
Cyclic Impact ◽  
The Impact

High in-situ stress and frequent dynamic disturbances caused by the mining process in deep coal mines can easily induce dynamic disasters such as coal burst. We conducted laboratory experiments to assess the effects of the axial stress loading and dynamic cyclic impact loading on the dynamic mechanical properties of burst-prone coals by using a modified split Hopkinson pressure bar (SHPB). Comparisons were made using two types of burst-prone and burst-resistant coal samples. The mineral components, organic macerals, and dynamic mechanical features of both burst-prone and burst-resistant coal samples were comparatively analyzed based on the obtained X-ray diffraction (XRD), optical microscope observations, and dynamic compressive stress-strain curves, respectively. The results of the microstructure analysis indicated a larger difference between the minimum and maximum reflectances of vitrinite for burst-prone coal. Compared to the burst-resistant coal samples, the burst-prone coals contained less corpocollinite and fusinite. While applying a high axial static load combined with cyclic impact load, the coal samples showed the characteristics of fatigue damage. The results also demonstrated that preaxial stress affected the burst resistance of coal samples. The greater the preaxial stress was, the less the coal samples could withstand the dynamic cyclic impact load. In comparison to the burst-resistant coal sample, the burst-prone coal sample showed a larger dynamic compressive strength and a lower deformation. They were also more positively capable of the propagation and activation of the coal burst. We believe that the results of the study are conducive to further understanding of the distribution of microcomponents of burst-prone coals. The results are also beneficial for realizing the dynamic mechanical characteristics of burst-prone coals under the impact of cyclic dynamic load.

Effect of various enzymatic treatments on the mechanical properties of coir fiber/poly(lactic acid) biocomposites

2019 ◽  
pp. 089270571986461
Author(s):  
Kubra Coskun ◽  
Aysenur Mutlu ◽  
Mehmet Dogan ◽  
Ebru Bozacı
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Test Results ◽  
Fiber Reinforced ◽  
Remarkable Effect ◽  
The Impact

The effects of enzymatic treatments on the properties of coir fiber-reinforced poly(lactic acid) (PLA) were not found in the literature. Accordingly, the effects of various enzymatic treatments on the mechanical performance of the coir fiber-reinforced PLA composites were investigated in the current study. Four different enzymes, namely lipase, lactase, pectinase, and cellulase, were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis. According to the test results, the use of enzyme treated coir fibers affected the mechanical properties except for the flexural properties with different extents depending upon their type. The tensile strength increased with the treatments of lipase and lactase, while the treatments with pectinase and cellulase had no remarkable effect. The impact strength was improved with enzymatic treatments except for pectinase. All enzymatic treatments improved the elastic modulus below the glass transition temperature. In brief, enzymatic treatments improved the interfacial adhesion between coir fiber and PLA via the waxes and fatty acids removal and/or the increment in surface roughness.

scholarly journals Transformation Kinetics and Mechanical Properties of Copper-Alloyed and Copper-Nickel Alloyed ADI

2018 ◽  
Vol 925 ◽  
pp. 181-187 ◽  
Author(s):  
Marcin Górny ◽  
Edward Tyrała ◽  
Gabriela Sikora
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Properties ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
X Ray Diffraction ◽  
Dispersed Particles ◽  
Initial Stage ◽  
Ni Additions ◽  
Effect Of Copper ◽  
The Impact

In this study the effect of copper and nickel in shaping the structure and properties of ADI (Austempered Ductile Iron) was investigated. The austenitization and austempering transformations were studied in order to follow the changes exhibited in transformation kinetics. The dilatometric results indicated that the addition of Cu and the addition of both Cu and Ni resulted in reducing relative expansion during austenitization, due to a larger pearlite fraction in the microstructure. In the initial stage of the austempering process, the addition of Cu, and to a greater extent, additions of both Cu and Ni led to a reduction in the transformation rate, shifting the maximum transformation rate values toward longer times. X-ray diffraction, dilatometric, metallographic and magnetic examinations allowed us to determine the phases fraction in the structure of ADI with the presence of Cu and Ni. From SEM-EDS analysis, it follows that in the copper alloyed ADI, highly dispersed particles are formed containing Mg and Cu, whose size does not exceed <1 µm. The exhibited mechanical properties were determined as a function of Cu and Ni additions and also variable austempering period of time. It was found that the addition of Cu resulted in increased tensile strength and hardness but simultaneously decreased the impact strength of ADI. The outcome of this work indicates that in order to obtain a satisfactory combination of static and dynamic mechanical properties of ADI, an optimal combination - aside from proper heat treatment - Cu and Ni should be selected.

scholarly journals The Influence of Milling Conditions on the Ni3Fe Alloyed Powder

2015 ◽  
Vol 13 ◽  
pp. 75-82
Author(s):  
Călin Virgiliu Prică ◽  
Cristina Daniela Stanciu ◽  
Florin Popa ◽  
Ionel Chicinaş
Keyword(s):  
High Frequency ◽  
Rotation Speed ◽  
High Energy ◽  
Milling Process ◽  
Planetary Mill ◽  
Energy Conditions ◽  
Particle Sizes ◽  
Grain Sizes ◽  
Disk Rotation ◽  
The Impact

The mechanosynthesis of Ni3Fe intermetallic compound was carried out in a planetary mill. The effects of milling parameters such as balls diameters and ball milling speed defined by the vials rotation speed (ω) and the disk rotation speed (Ω), on morphology, microstructure and particle sizes of Ni3Fe powder were studied. It was found that the impact frequency represented by the number of balls from vials is an important parameter a milling process. The smaller grain sizes and particle was obtained when milling process was performed in high frequency rate of impacts together with high balls velocity, meaning high energy conditions.

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