Effects of cellulose nanocrystals as extender on physical and mechanical properties of wood cement composite panels

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8291-8302
Author(s):  
Mona Shayestehkia ◽  
Habibollah Khademieslam ◽  
Behzad Bazyar ◽  
Hossein Rangavar ◽  
Hamid Reza Taghiyari

The effects of cellulose nanocrystal (CNC) particles were investigated relative to the physical, mechanical, and microstructural properties of wood cement composite panels. Wood and cement were mixed at three ratios of 1:3, 1:3.5, and 1:4. Calcium chloride was added at 3 and 5%. CNC was added to the mixture at five levels (0, 0.1, 0.2, 0.5, and 1%, based on dry weight of cement). The results showed that CNC content of 0.5% had the best impact on the properties. The overall trend showed that with the addition of CNC, tensile, flexural, and physical properties of the composites were considerably enhanced. Scanning electron microscopy demonstrated that the addition of CNC was associated with an improved integrity in the micro-structure of panels.

Author(s):  
SadıkAlper Yıldızel

Structural plaster properties of the residence type buildings that were constructed during prerepublic and early republic periods in Demirci were investigated within the scope of this study. Samples taken from the existing structures were dried in laboratory conditions and made ready for micro-structure examination. Proper samples were examined with scanning electron microscopy (SEM) with the sensitivity of 5 nm and a magnification of 20.000 times, and the optical microscope (magnification: 250 x). In the light of obtained results, it has been determined that the microstructure of the composite used in the Demirci county in the preRepublican period and early republic period is similar to the resultant of mixes produced with the modern fiber added composite production technology. It is thought that this study will contribute to the study of the production of the related building materials to be improved in the future within the limits of the district.


2013 ◽  
Vol 86 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Hedayatollah Sadeghi Ghari ◽  
Zahra Shakouri

ABSTRACT Research was undertaken on natural rubber (NR) nanocomposites with organoclays. A double-network (DN) structure is formed when a partially cross-linked elastomer is further cross-linked during a state of strain. Two methods were used in the preparation of NR/organoclay nanocomposites: the ordinary method (single-network NR nanocomposite) and double-networked NR (DN-NR) nanocomposites. The single-networked NR nanocomposites were used for comparison. The effects of organoclay (5 phr) with a different extension ratio on curing characteristics, mechanical properties, hardness, swelling behavior, and morphology of single- and double-networked NR nanocomposites were studied. The results showed that double-networked NR nanocomposites exhibited higher physical and mechanical properties. The tensile strength of DN-NR nanocomposites increased up to 33 MPa (more than four times greater than that of pure NR) and then decreased with an increasing extension ratio. Modulus and hardness continuously increased with an increased extension ratio. The microstructure of the NR/organoclay systems was studied by X-ray diffraction and field emission scanning electron microscopy. The effects of different extension ratios on the dispersion of organoclay layers in the nanocomposites were investigated. Generally, results showed that the optimized extension ratio in DN nanocomposites was equal (or about or around) to α= 2.


2014 ◽  
Vol 50 (1) ◽  
pp. 87-90 ◽  
Author(s):  
E. Aldirmaz ◽  
I. Aksoy

In this study, some physical and mechanical properties in Cu-9.97%Al-4.62%Mn (wt%) alloy were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and compression deformation test. Bainite phase were obtained in the samples according to SEM and XRD analyses. Compression stress was applied on the alloy in order to investigate the deformation effect on the bainite phase transformation. On the surface of the Cu-9.97%Al-4.62%Mn alloy after the deformation, both bainite and martensite variants formed.


2020 ◽  
Vol 10 (3) ◽  
pp. 5845-5850
Author(s):  
B. Uzbas ◽  
A. C. Aydin

The effects of using different ratios of silica fume on the mechanical and microstructural properties of hardened cement paste and concrete were investigated in this study. Portland cement was replaced with 5%, 10%, 15%, and 20% silica fume (SF) by weight. Microstructural properties of obtained samples were investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The XRD analysis showed that the ratio of calcium hydroxide (CH), which is produced by hydration, decreases depending on the concrete age and the amount of silica fume. The SEM analysis showed that the use of silica fume decreases gaps and calcium silicate hydrate (C-S-H) which is also a hydration production. Silica fume content of up to 15% improved the observed mechanical and microstructural properties of concrete. At the optimum value of 15%, improvement in the paste was observed due to the filler effect and the reaction between the silica fume and calcium hydroxide, leading to a reduction in calcium hydroxide in the concrete.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1846-1849 ◽  
Author(s):  
Ying Wang ◽  
Pan Pan Yang

The physical and mechanical properties and microstructure of Q2loess are of great theoretical and practical significance. Through studying these properties which Q2loess samples are taken in the Xi'an city of Lin-tong District of Mount Li, the results show that: (1)Natural water content, wet density, liquid and solid index, shear strength, collapsible coefficient compressive modulus; (2)By means of the scanning electron microscope to study the picture of the loess micro-structure, there are some preliminary understanding of micro-structure’s basic characteristics; (3)Using scanning electron microscopy techniques to observe the loess micro-structure, As the performance of the loess micro-structure’s basic unit-body and its arrangement form, the loess micro-structure is the reflection of its physical and mechanical properties, Meanwhile the change of physical and mechanical properties also show the unstability of the loess micro-structure.


2018 ◽  
Vol 156 ◽  
pp. 08014
Author(s):  
Agung Mataram ◽  
S. Rizal ◽  
Estu Pujiono

The membrane is a layer formed from fine fibers are used as a filter. In this research, measured the tensile strength and pore size of the membrane that is made in three variations of a specimen with a mixed composition of different Polyvinilidene Fluoride 17.5%, 20%, 22.5%., membrane made using Polyvinilidene Fluoride polimer granules and N,N-Dimethylformamide as solvent and silver nitrate. Membrane molded into standardized test specimens and tested with a device Adhesion Tearring Strength Tester. The results show an increase in the value of the tensile test of 404.8356 KPa to the composition of 17.5%, 507.3598 KPa for composition of 20% and 603.7218 KPa to a composition of 22.5%. For testing the microstructure using a Scanning Electron Microscopy with the resulting increase in pore diameter, for the range of 558.4 nm-781.8 nm are void to the composition of 17.5%, range 670.1 nm - 781.8 nm without voids for the composition of 20% and 1.117 μm-1.228μm without voids on a composition of 22.5


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2862
Author(s):  
Myung-Kwan Lim ◽  
Kyung-Yong Nam

During concrete construction in winter, the concrete performance is generally improved by adding a chemical admixture or providing protection using tents and hot-air blowers. However, long-term strength or safety accidents may occur due to the installation and removal of the tents. This study considered insulated gang forms to improve formwork methods. In this regard, the microstructure and micropore characteristics of concrete were investigated experimentally to examine the insulated gang form effect on the physical and mechanical properties of concrete. The micropore characteristics were investigated through scanning electron microscopy. The results confirm that applying insulated gangs improves workability and safety without adding chemical admixture. Moreover, the application of insulated gang forms reduces the use of tents and hot-air blowers. Therefore, insulated gangs provide excellent initial quality to the concrete.


2015 ◽  
Vol 4 (3) ◽  
pp. 23-28
Author(s):  
Fadhilla Asyri ◽  
Kartini Noor Hafni ◽  
A. Haris Simamora

This study aims was to determine the effect of palm oil fuel ash (POFA) composite as filler on the physical and mechanical properties of high impact polystyrene (HIPS) composites. The research methodology included preparation of raw materials, treatment POFA (hydration process of POFA), mixing using tumbler and then extruder, molding composite specimens, and testing. The variables used were weight ratio of HIPS with 140 mesh POFA at 95/5; 92.5/7.5; 90/10. The composites were tested by Fourier Transform Infrared (FTIR), ash content, specific gravity, tensile strength, elongation at break, impact strength, hardness test, and Scanning Electron Microscopy (SEM). The results of FTIR characterization shows the formation of –OH bonding that was suspected as Si-OH or Si-hydrat. Results of physical and mechanical properties of the composites shows that increase of the filler composition in HIPS-POFA composites until the ratio of 90/10, increase the specific gravity to 7.2% of the original, tensile strength did not change significantly to 28.4 MPa, elongation at break decreased to 2.7%, impact strength decreased to 3.183 KJ/m2, and the hardness increased to 110.5, and Scanning Electron Microscopy (SEM) test show the transformation of POFA structure on treated POFA and intercalation between the matrix and POFA.


2013 ◽  
Vol 405-408 ◽  
pp. 2928-2932
Author(s):  
Krit Prasertlar ◽  
Krit Chaimoon

This paper presents some experimental results on the physical and mechanical properties of reactive powder concrete (RPC) using two different characteristics of densified silica fume (f1 and f2). The silica fume/cement ratio (f/c) varied from 15% to 35% by weight. The flow, the micromorphology by scanning electron microscopy (SEM) and the compressive strength at the ages of 3, 7 and 28 days were studied. The effects of the silica fume agglomerations on the properties of the RPC were considered and discussed. The test results indicated that the properties of RPC depended on the type of silica fume, amount of silica fume and amount of superplasticizer used.


Mechanik ◽  
2018 ◽  
Vol 91 (5-6) ◽  
pp. 438-442
Author(s):  
Magdalena Szutkowska ◽  
Marek Boniecki ◽  
Marcin Podsiadło ◽  
Andrzej Kalinka

The present study reports mechanical properties obtained by reinforcing alumina composites with Ti(C,N) in amount 30 wt.% prepared on the basis micro and nanoscale trade powders. The pressureless sintering PS in a vacuum and SPS method of sintering were used. Vickers hardness, density, Young modulus, wear resistance were evaluated. Fracture toughness (KIC) at ambient and elevated temperatures up to 1073 K, characteristic for tool work was measured. Physical and mechanical properties of the composites Al2O3/Ti(C,N)/ZrO2 based on the powders in microscale were compared with composites containing nanoscale powders in a range from 17 to 36 wt.%. Tested composites with nanoscale powders content reveal lower KIC (approx. 10÷30%) at ambient temperature in comparison to composites based on powders in microscale. However, in the elevated temperatures their fracture toughness increases up to 30%. The observation of the microstructure of tested composites was carried out using scanning electron microscopy.


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