scholarly journals Structural and mechanical properties of graded composite Al2O3/Ni obtained from slurry of different solid content

2016 ◽  
Vol 1 ◽  
pp. 305-312 ◽  
Author(s):  
J. Zygmuntowicz ◽  
A. Miazga ◽  
K. Konopka ◽  
W. Kaszuwara
2012 ◽  
Vol 200 ◽  
pp. 287-291 ◽  
Author(s):  
Quan Xiao Liu ◽  
Wen Cai Xu ◽  
Yan Na Yin

Cationic polyacrylate emulsion was used as surface sizing agent and the effects of emulsion properties on paper mechanical properties were studied. The mechanical properties of sized paper gradually increased with the increase of solid content, viscosity and positive charge density of emulsion and decreased with the increase of particle size of emulsion. Tensile strength, folding endurance and tearing strength on machine direction were increased 33.62%, 11.99%, 6.79% respectively when the paper with single emulsion layer was used oven drying methods.


2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Dendi Prayoga ◽  
. Dirhamsyah ◽  
. Nurhaida

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30%  and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with  pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon  with composition a ratio of  rice husk 50%: sengon 50% , 16% adhesive content  16%, with density value of  0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon


2021 ◽  
Author(s):  
Jing-Siang Jhan ◽  
Chih-Cheng Chen ◽  
Yu-Chi Liu ◽  
Hsing-I Hsiang

Abstract Yttria-stabilized tetragonal zirconia (YTZP) ceramics with high densification and superior mechanical properties were obtained using gel casting technology and a two-stage sintering process. Well-dispersed Nano-sized (94 nm) zirconia slurry with high solid content (45vol%) was prepared for gel casting using Dolapix CE64 as the dispersant. As the dispersed slurry was added epoxy monomer (EGDGE) and polymerization initiator (DPTA), Dolapix CE64 promoted gelling, leading to an abrupt increase in the slurry viscosity. As Dolapix CE64 was added into the slurry, its functional carboxyl groups reacted with EGDGE, resulting in a decrease in gelling incubation time and an increase in viscosity, hence, leading to gel casting failure. The addition of hydroquinone (HQ) into the slurry can be used to delay the polymerization and extend the gel casting working time. After gel casting, the temperature was raised to above 60o C to promote the polymerization, leading to an increase in the green strength.A two-stage sintering process was used to control the grain growth. The first stage sintering temperature was chosen at 1300oC, where the relative density reached 83%. In the second sintering stage, the temperature was lowered to 1240°C and soaked for 24 h to inhibit grain growth (mean grain size of 195 nm) and continue densification to a relative density of above 99%. Vickers hardness of 15.2GPa, fracture toughness of 7.8MPa.m1/2, and flexural strength of 771MPa can be obtained for the sample prepared using gel casting technology with a two-stage sintering process.


2020 ◽  
Vol 49 (4) ◽  
pp. 283-294
Author(s):  
Abd El-Wahab H. ◽  
Farouk Abd El-Monem ◽  
Naser M.A. ◽  
Hussain A.I. ◽  
El-Shahat H.A. Nashy ◽  
...  

Purpose The purpose of this paper is devoted to application of the emulsion polymer of poly(methyl methacrylate-co-butyl acrylate) prepared with in situ nano-silica as a novel tanning agent of hide to partly or totally replace chrome salt and to improve physical, thermal and mechanical properties of the tanned leather and to reduce the environmental impact of chrome tanning effluent. Design/methodology/approach Polymer/nano-silica hybrid emulsions were prepared via in situ seed emulsion polymerisation. The prepared polymers were characterised for solid content, molecular weight, viscosity, drying time, minimum film-forming temperature (MFFT) and microstructures (via transmission electron microscopy). The mechanical, thermal and surface morphological (by scanning electron microscope) properties of the treated samples were also investigated. The influences of the increase in the content of organic nano-silica on the properties of the tanned leather are discussed. Findings It was found that the viscosity, the particle size and the solid content of the prepared polymers increased as the content of the nano-silica increased while gloss and drying time of the resulting polymer film decreased. Tanning buffalo hide by Polymer F (containing a high content of nano-silica) gave desirable properties in terms of tensile strength, thermal stability and shrinkage temperature. Research limitations/implications This paper discusses the preparation and the characterisation of emulsion polymers with in situ nano-silica and their application in tanning process to enhance and improve the leather quality, as well as reduce the use of chrome tanning materials and consequently chrome tanning waste. Practical implications The tanned leather showed an improvement of physico-mechanical properties and enhancement of thermal stability. Furthermore, the tanned leather has uniform colour, softness and firmness of grain. All these promising results provide evidence to support the applicability of the prepared co-polymer/nano-silica emulsions as an efficient tanning agent that also provides lubricating properties for leather. Originality/value Since May 2015, REACH Annex XVII restricts Cr(VI) in leather articles or leather parts of articles that come into contact with skin to a concentration of less than 3 mg/kg. Cases of discovery of Cr(VI) in leather papers have been reported by the European rapid alert system on dangerous consumer products (RAPEX). The emulsion poly (methyl methacrylate-co-butyl acrylate) with in situ nano-silica that has been developed via the study reported in this paper is one of the better technologies for the reduction of chromium ratio used in tanning industry.


Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 922
Author(s):  
Jiajian Li ◽  
Erol Yilmaz ◽  
Shuai Cao

Understanding the flow process of cemented tailings backfill (CTB) is important for successful pumping into underground stopes. This study examines the effects of solid content (SC), cement/tailings (c/t) ratio, and curing time (CT) on rheological and mechanical properties of CTB mixes. The slurry concentration of the mixes was 65, 67, and 69 wt. %, with c/t ratios ranging from 1:4 to 1:20. Unconfined compressive strength (UCS) tests were performed on hardened CTB mixes after curing 3, 7, and 28 days. The rheological properties of CTB slurries are mainly related to SC. The yield stress and viscosity of fresh mixes increase with increasing SC, but the pipeline resistance loss (PRL) also increases with increasing SC. According to the analysis of variance, the SC and flow rate are the most significant parameters which greatly affect the PRL performance. The c/t and CT parameters are the most significant parameters for affecting the shrinkage rate. The findings offer a reference for theoretical optimization for mine filling systems of similar type.


2015 ◽  
Vol 816 ◽  
pp. 27-32 ◽  
Author(s):  
Song Lin Liang ◽  
Qing Song Ma ◽  
Hai Tao Liu

In order to efficiently fabricate dense three-dimensional carbon fiber reinforced mullite matrix composites (3D C/mullite), two kinds of Al2O3-SiO2sols with high solid content were used as raw materials. The ceramic yield and mullitization behavior of the sols and the densification process were investigated. It is indicated that the two sols have proper solid content and ceramic yield and can be completely transformed into mullite at 1573K, which make them be able to prepare composites. 3D C/mullite composites with a porosity of ∼25% were prepared by repeating less than 20 cycles of infiltration-drying-heating of sols, and the microstructures and mechanical properties were examined. The results suggest that the sol with smaller particle size derived composites exhibit well-sintered dense matrix and physically stronger interfacial bonding, which are beneficial to improve load-bearing and load-transferring capacity of matrix. As a result, this composites show much higher mechanical properties. The flexural strength and modulus are 2.4 times and 1.3 times as those of the sol with larger particle size derived composites, respectively.


Author(s):  
Mohammad Ateeq Aldoasri ◽  
Sawsan Darwish ◽  
Mahmoud Adam ◽  
Nagib Elmarzugi ◽  
Sayed Ahmed

Environmental deterioration factors are constantly increasing, causing unwanted aesthetic changes to stone artworks due to exposure to various physical and chemical deterioration factors. Inorganic nanoparticle-filled polymer composites have extended their multiple functionalities to various applications, including cultural heritage conservation. Therefore, this study has examined the effects of clay, SiO2, Ca(OH)2 and CaCO3 nanomaterials in the enhancement of the physicomechanical properties of limestone monuments, the aim of the present work being to evaluate comparatively the effectiveness of nanoparticles as consolidation and protection material for limestone artworks. The nanoparticles were added to an acrylic-based copolymer (polyethylmethacrylate (EMA)/methylacrylate (MA) (70/30), in order to improve its physiochemical and mechanical properties, and produced a significant improvement in the ability of the polymers to consolidate and protect the stone. The synthesis process of nanoparticles/polymer nanocomposite has been prepared by an in situ emulsion polymerization system. The nanocomposites contained poly (EMA/MA) with a solid content of 3% [poly (EMA/MA)] in the absence and presence of 5% nanoparticles (0.15 g nanoparticles). Samples were subjected to artificial aging by relative humidity/temperature and acid/salt crystallization weathering to show the optimum conditions of durability and the effectiveness of the nano-mixture in improving the physical and mechanical properties of the stone material. To ensure that the treatment had no negative effects on the physical characteristics of the limestone, the properties of the treated limestone samples were evaluated comparatively before and after artificial aging by the conduct of microstructural (phase morphology studied by means of scanning electron microscopy) and aesthetic (colour and lightness measured by spectrophotometry) analyses. Also used were measurement of static contact angle of water droplets on the surface of the samples, total immersion water absorption, compressive strength, and abrasion resistance test. Results demonstrated that the addition of nanoparticles to an acrylic-based polymer enhanced its capability to consolidate and protect the limestone samples.


2021 ◽  
Vol 32 (4) ◽  
pp. 687-691
Author(s):  
Aniek Setiya Budiatin ◽  
Maria Apriliani Gani ◽  
Chrismawan Ardianto ◽  
Samirah ◽  
Sahrati Yudiaprijah Daeng Pattah ◽  
...  

Abstract Objectives Biomaterials are widely used as drug delivery systems targeting bone tissue, such as to treat bone infectious disease. However, the addition of drugs to biomaterials weakens their mechanical properties. Crosslinkers are compounds that improve the mechanical properties of biomaterials. This study aims to determine the effect of glutaraldehyde (GTA) as a crosslinker on the characteristics of bovine hydroxyapatite-gelatin-based bone scaffold with gentamicin as antibiotics (BHA-GEL-GEN-GTA). Methods BHA-GEL-GEN-GTA scaffold with GTA solid content ranging from 0.1 to 1.4 wt% was made by direct compression. The compressive strength test was carried out using autograph. Scaffold degradation test was carried out by dissolving the scaffolds in PBS. Scaffold toxicity was performed by MTT assay using BHK-21 fibroblast cells. Results There was a significant difference in the scaffolds’ compressive strength due to differences in GTA volume. Scaffold crosslinked using GTA with solid content 0.1 and 0.2 wt% in 2 mL solution had higher compressive strength than those in 1 mL solution. Furthermore, GTA with solid content 0.6, 1, 1.2, and 1.4 wt% showed higher compressive strength than those without GTA. Degradation test results showed that GTA increased the percentage of weight loss and swelling of the scaffold. The scaffold exhibited a nontoxic profile in MTT assay. Conclusions GTA with optimum solid content shows great compressive strength, stable swelling profile with low percentage of scaffold’s weight loss, and is considered as nontoxic.


2019 ◽  
Vol 20 (7) ◽  
pp. 1790 ◽  
Author(s):  
Lizette Morejón ◽  
José Angel Delgado ◽  
Alexandre Antunes Ribeiro ◽  
Marize Varella de Oliveira ◽  
Eduardo Mendizábal ◽  
...  

Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%–87%, pores in the range of 280–550 µm and connectivity density up to 43 mm−3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.


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