bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanically Activated Synthesis of Tungsten Carbide Nanoparticles from Tungsten Oxide
Authors: Kariminejad Arash , Ghasemi Behrooz , Milani Milad , Ghorbani Hassan , Azadeh Mohammad
Published: November 2013

Solid state carbothermic reduction of tungsten oxide (WO3) to nanosized tungsten carbide (WC) particles was achieved by heating mechanically activated mixture of tungsten oxide and graphite at different temperatures under vacuum condition. KCl and Ni were added to the mixture for some samples. The morphology and chemical composition of products, as well as particles size and their distribution were compared by X-ray diffraction and field emission scanning electron microscopy. Mechanical activation of WO3-C powder mixture did not yield WC phase whereas it was possible to produce WC nanoparticles by heating at 1250 °C for 2 h. KCl additive caused fine and homogeneous particle and Ni additive assisted the growth of WC particles.
Nickel Oxide Coated on Pretreated MWCNTs as an Electrode for Supercapacitor
Authors: Mahmoudi Lida , Mahboubi Farzad , Yazdi Moreteza Saghafi
Published: November 2013

Nickel oxide/carbon nanotubes (NiO/CNTs) composite materials for supercapacitor are prepared by chemically depositing of nickel hydroxide onto CNTs pretreated by ultrasonication and followed by thermal annealing at 200-300°C. A series of NiO/CNTs composites with different weight ratios of CNTs and different annealing temperature are synthesized via the same route. The scanning electron microscope (SEM) images show that the nucleation of the nickel hydroxide formed on the outer walls of CNTs due to ultrasonic cavitations, and then nickel oxide coated uniformly on the outer surface of the individual CNTs after thermal annealing. The NiO/CNTs electrode presents a maximum specific capacitance of 254 F/g as well as a good cycle life in 2 M KOH electrolyte. The good electrochemical characteristics of NiO/CNTs composite can be attributed to the three-dimensionally interconnected nanotubular structure with a thin film of electroactive materials.
Dispersion of Multi Walled Carbon Nanotubes within 3 mol. % Yttria Stabilized Zirconia Based Ceramics: A Comparative Study of Methods
Authors: Ermagan Roya , Taheri Mahdiar , Zahedi Ali Mohammad , Golestanifard Farhad
Published: November 2013

Achieving an appropriate dispersion of Carbon Nanotubes (CNTs) within a ceramic matrix should be referred to as the main challenge for the synthesis of CNTs reinforced ceramics with enhanced toughening properties. In the present paper, dispersion of 1 wt% MWCNTs within 3YTZP based ceramics has been investigated through the comparison of three conventional approaches based on using surfactants, functionalization, and planetary milling. Addition of 2 wt% Sodium Dodecyl Sulfate (SDS) as the surfactant material followed by 2 hours ultrasonication was found successful to disperse carbon nanotubes in a water media, while chemical functionalization of the CNTs surface using a mixture of H2SO4/HNO3 (3:1) could result in identical well dispersed powder mixtures. Formation of functional groups on the surface of CNTs was confirmed by FTIR spectroscopy and efficiency of the above methods to result in well dispersed powders was detected using UV-Vis spectroscopy. The surfactant method was, accordingly, found to result in the highest dispersion of nanotubes within the ceramic microstructure. In the planetary milling method, well dispersed CNTs within 3YTZP particles could be attained through the optimization of processing conditions such as 24 h milling time, 250 RPM, and 2 BPR. The accuracy of the above results could be verified by SEM as well as Raman spectroscopy. On the other hand, although the dispersed powders provided through functionalization and planetary milling methods revealed CNTs bundles in few scopes of the SEM results and minor damages were also observed in the Raman spectroscopy report, they were both at acceptable levels.
Modified Synthesis Temperature of Ba3 Co1.7 Ni0.1 Cu0.1 Mn0.1 Fe24 O41 Z-Type Ferrite Nanoparticles Prepared by Co-Precipitation Method
Authors: Pourhosseini Asl Mohammad Javad , Ghasemi Ali , Gordani Gholam Reza
Published: November 2013

In this study, the low temperature synthesis of barium-Z type hexaferrite nanoparticles was considered. In this manner, the Z-type hexaferrite with the chemical composition of Ba3 Co1.7 Ni0.1 Cu0.1 Mn0.1 Fe24 O41 was synthesized at different temperatures of 900, 1000 and 1100 0C for 3hr. An X-Ray diffraction, field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM) analysis were carried out to investigate structural and magnetic properties of samples. XRD results showed that the Z-type ferrite phase was formed in all samples. However, At the low temperature synthesis (T=900 0C), the Ba2Me2Fe12O22 and BaFe2O4 phases were also detected. FE-SEM micrographs showed that with increasing the synthesis temperature, the particle size was increased. It was found that the saturation of magnetization was slightly increased from 54 to 55. 5emugr with an increase in synthesis temperature from 900 to 11000C, while the coercivity increased initially from 670 Oe to 860 Oe and then decreased to 488 Oe. The results also indicated that the temperature of 10000C was the optimum synthesis temperature of Ba-Z type hexaferrite nanoparticles, which was much lower than that of Z-type hexaferrite produced by previous researchers.
Effect of Mn Dopant on Lattice Parameters and Band Gap Energy of Semiconductor ZnO Nanoparticles
Authors: Zolfaghari Mahmoud , Chireh Mahshid
Published: November 2013

ZnO belongs to the II-VI semiconductor group with a direct band-gap of 3.2-3.37 eV in 300K and a high exciton binding energy of 60 meV. It has good transparency, high electron mobility, wide, and strong room-temperature luminescence. These properties have many applications in a wide area of emerging applications. Doping ZnO with the transition metals gives it magnetic property at room temperature hence making it multifunctional material, i.e. coexistence of magnetic, semiconducting and optical properties. The samples can be synthesized in the bulk, thin film, and nanoforms which show a wide range of ferromagnetism properties. Ferromagnetic semiconductors are important materials for spintronic and nonvolatile memory storage applications. Doping of transition metal elements into ZnO offers a feasible means of tailoring the band gap to use it as light emitters and UV detector. As there are controversial on the energy gap value due to change of lattice parameters we have synthesized Mn-doped ZnO nanoparticles by co-precipitation method with different concentrations to study the effect of lattice parameters changes on gap energy. The doped samples were studied by XRD, SEM, FT-IR., and UV-Vis. The XRD patterns confirm doping of Mn into ZnO structure. As Mn concentrations increases the peak due to of Mn impurity in FT-IR spectra becomes more pronounces hence confirming concentrations variation. We find from UV-Vis spectra that the gap energy due to doping concentration increases due to the Goldschmidt-Pauling rule this increase depends on dopant concentrations and increases as impurity amount increases.
On the Vibrational Behavior of Piezoelectric Nano-Beams
Authors: Rahmani Omid , Noroozi Moghaddam Mohammad Hosein
Published: November 2013

In this article surface effects are considered to study the electromechanical coupling behavior of piezoelectric nanobeams with the non-local Euler-Bernoulli beam theory. The equation of motion for piezoelectric nanobeams with considering both surface effect and nonlocal effect is achieved and exact term for natural frequencies is derived for simply supported conditions. In the following the axial load effect on the natural frequencies piezoelectric nanobeams has been studied.
Effect of Fluoride Concentration and Water Content on Morphology of Titania Nanotubes in Ethylene Glycol Solution
Authors: Naghizadeh Meysam , Ghannadi Saber , Abdizadeh Hossein , Golobostanfard Mohammad Reza
Published: November 2013

Titanium dioxide (TiO2) nanotube arrays were prepared at room temperature by electrochemical anodization of a pure titanium foil in electrolyte solutions containing ethylene glycol as a solvent and de-ionized water and ammonium fluoride as additives. Since the morphology and size of TiO2 nanotubes play critical roles in determining their performance, the control of geometrical parameters of the nanotube arrays including length and inner diameter are of great importance. The present research demonstrates the significant effects of fluoride concentration and water content in anodizing electrolyte on formation of nanotubes and their dimensions. Scanning electron microscope investigation shows that nanotube arrays are no longer formed in very low or very high concentration of ammonium fluoride. Also, increase in fluoride concentration causes increase in lengths and inner diameters of the nanotubes. Moreover, it is evident that the maximum nanotube growth rate was achieved in medium amount of water. In addition, it is found that the nanotube inner diameter increases by adding more water to the solution.
Synthesis of Hard Carbon as Anode Material for Lithium Ion Battery
Authors: Khosravi Mohsen , Bashirpour Neda , Nematpour Fatemeh
Published: November 2013

Hard carbon (HC) is a kind of carbon that is difficult to be graphitized and usually is fabricated from pyrolysis of polymers such as phenolic resins, epoxy resins and pitch. From the structural point of view, HC is highly irregular and disordered, and primarily consists of single-layered carbon atoms that are closely and randomly connected. In this work, a sample of HC was synthesized through pyrolysis of oxidized pitch at high temperature (800 °C) under nitrogen atmosphere. XRD analysis demonstrated that the HC has higher d-spacing and lower stacking height than graphite. Elemental analysis showed that the synthesized HC have the [/[ atomic ratio of 0.22. Electrochemical tests showed this non-graphitized carbon has higher capacity (600 mAhg-1) than the theoretically maximum capacity of 372 mAhg-1for C6Li, indicating that the ratio of Li to C atoms is higher than 1/6 and the produced HC is suitable as anode material for Lithium ion battery.
Study on Color Change of Brown Sapphire in Changle, Shandong
Authors: Zheng Yu Zhu , Zhao Kun Yu , Tang Xue Lian , Xie Zu Hong , Zu En Dong
Published: November 2013

Most Shandong sapphires color are indigo blue, green and brown yellow, these deep color influence their commercial value. This paper makes a comparative study of the traditional heat treatment and heat diffusion treatment on brown series of sapphire of Shandong. The results show that heat treatment is helpful to improve the transparency of Shandong sapphire, but cannot produce ideal color, and it also has no obvious effect on its internal features. However, diffusion treatments after adding TiO2 can obtain comparatively ideal color, which is blue-green to blue. And the transparency and dark mineral inclusions are improved.
Sulfur and Lead Isotopic Geochemistry of the Shidi Pb-Zn Deposit in Xiushan County, Chongqing
Authors: Xiang Xiao Jun , Shuang Yan , Gong Kui
Published: November 2013

The Shidi Pb-Zn deposit is located in Xiushan County, southern Chongqing, and its orebodies were hosted in marine carbonates of the Cambrian Pingjing Formation. The authors selected sulfide minerals from the deposit for the analysis of sulfur and lead isotopic compositions. Theδ34S values of sulfide minerals vary from 10.8 to 15.6, with an average value of 13.52, indicating these sulfide materials were mainly derived from marine sulfate reduction. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios for sulfide minerals vary within the ranges of 18.319~18.422, 15.740~15.784 and 38.355~38.511, respectively. In the diagrams of Zartman, the Pb isotopic compositions of sulfide minerals fall into the regional upper crust lead zone. According to the characteristics of sulfur and lead isotopic compositions of the Shidi Pb-Zn deposit, the ore-forming materials might have come from the black shales of the Lower Cmabrian Niutitang Formation.
Synthesis and Exchange for Li+ of Spinel Type Material LiMn0.75Ti0.5O3
Authors: Jiang Jin He
Published: November 2013

LiMn0.75Ti0.5O3 was prepared by a solid state reaction crystallization method. The acid treatments of LiMn0.75Ti0.5O3 caused Li2+ extractions of more than 75%, while the dissolutions of Mn4+ and Ti4+ were less than 13%. The experimental results have proved that the acid-treated sample has a capacity of exchange 4.1mmol·g-1 for Li+ in the solution.
Effect of Al and Zn Content on the Preparation of Semisolid Mg-Al-Zn Magnesium Alloy
Authors: Zhang Qian Qian , Chen Wei Rong
Published: November 2013

The thermodynamic parameter and microstructure of three contents as-cast magnesium alloys were researched by phase picture, X-ray diffraction and thermodynamic analysis, whereafter prepared semisolid billets by strain induced melt activation (SIMA). The microstructure observation and rheology parameter analysis demonstrated that add zinc content consumedly reduced formation temperature of semisolid microstructure, decreased isothermal holding time, and accelerated microstructure evolution. With increasing zinc content, the semisolid morphology better and better that is propitious to semisolid process. The analysis verified that on the one hand, with increasing aluminum and zinc content the melting point of compound and the nucleation temperature of liquid phase decreased, and the nucleation quantity of liquid phase increased; on the other hand, with increasing alloy content the as-cast microstructure much finer, which to caused much more fine and spherical semisolid microstructure.
Effects of Mechanical Vibration and Pouring Temperature on Solidified Structure of Superalloy K4169
Authors: Xie Xiao Hua , Chen Le Ping , Xiao Cheng Bo , Tang Xin
Published: November 2013

The influences of different vibration amplitude and pouring temperature on solidified structure of superalloy K4169 under the action of mechanical vibration were investigated. The vibration amplitudes and pouring temperatures used were 1.5, 1.75 and 2 mm and 1380, 1430, 1480 and 1530°C, respectively. The experimental results show that application of mechanical vibration leads to increase in grain refinement and proportion of equiaxed grains of superalloy K4169. The dendrite growth is restrained and the microstructure is changed from well-developed dendrite grains to fine equiaxed grains. Grain size of the alloy decreases as vibration amplitude increases. With the increase of the pouring temperature, grain size of the alloy increases firstly, then decreases and the turning point is 1430°C. When the pouring temperature is 1380°C, grain size of the alloy with mechanical vibration treatment is the finest.
Managing Varnish of Turbine Oil
Authors: Fang Sheng , Gen Xian Lin
Published: November 2013

Varnish now becomes the severe problem of gas turbine, nuclear power plant and other industry which use lubricant oil and hydraulic fluid. The cause of varnish formation is heat, oxidation and contamination. Varnish can cause many turbine problems. The Membrane Patch Colorimetry (MPC) test can be used to measure varnish. Partial or all oil change, Filtration with Cellulose Media and System Chemical Cleaning can be applied to mitigate varnish.
The Dynamics Simulation of Tracked Vehicles on the Hard and Soft Ground Based on the RecurDyn
Authors: Zhou Chong Kai , Huang Ya Yu , Ni Li
Published: November 2013

In order to accurately study a tracked vehicle movement on the ground in hard and soft features, this paper uses multi-body dynamics simulation software RecurDyn tracked vehicle subsystems Track (LM), establishing a three-dimensional multi-body vehicle dynamics model. For tracked vehicles at an inclination of 10 degrees slope, through the soft and hard ground steering process dynamics simulation and comparative analysis. This paper provides an accurate basis for the future in-depth research on Tracked vehicle.
The Calculation of Train Slipstreams on Platform of Underground High-Speed Rail Station
Authors: Yang Wei Chao , He Chuan , Peng Li Min
Published: November 2013

This paper describes the results of numerical work to determine the flow structures of the slipstream and wake of a high speed train on platforms of underground rail station using three-dimensional compressible Euler equation. The simulations were carried out on a model of a simplified three-coach train and typical cross-section of Chinese high-speed railway tunnel. A number of issues were observed: change process of slipstreams, longitudinal and horizontal distribution characteristics of train wind. Localized velocity peaks were obtained near the nose of the train and in the near wake region. Maximum and minimum velocity values were also noticed near to the nose rear tip. These structures extended for a long distance behind the train in the far wake flow. The slipstream in platform shows the typical three-dimensional characteristics and the velocity is about 4 m/s at 6 m away from the edge of platform.
Analytical Prediction Model for Fatigue Crack Propagation Rate under Tension-Compression Loading
Authors: Sha Yu , Bai Shi Gang , Wang Ya Hui
Published: November 2013

Elastic–plastic finite element analyses have been performed to study the compressive stress effect on fatigue crack growth under applied tension–compression loading. The near crack tip stress, crack tip opening displacement and crack tip plastic zone size were obtained for a kinematic hardening material. The results have shown that the near crack tip local stress, displacement and reverse plastic zone size are controlled by the maximum stress intensity factors Kmax and the applied compressive stress σmaxcom under tension–compression. Based on the finite element analysis results, a fatigue crack propagation model using Kmax and σmaxcom as a parameters under tension–compression loading has been developed.The models under tension–compression loading agreed well with experimental observations.
Studies on Mechanical Properties of Mulberry Branches Scrimber
Authors: Chen Mei Ling , Wang Chuan Gui , Zhang Shuang Yan , Wu Heng , Wang Xiang , Pei Yun Wen
Published: November 2013

This paper presents the manufacturing process of scrimber by using mulberry branches and urea-formaldehyde. The effect of density, hot-pressing conditions and resin content on scrimbers mechanical properties was conducted. The results showed that the mechanical properties of the scrimber met the relative requirements in the density of 0.8 g/cm3 while the resin content was 12% and the hot-pressing conditions were in 1.5MPa, 100°C and 1.4min/mm. The MOR, MOE and IB of samples had reached 40.14MPa, 5024.20MPa and 0.44MPa under the best process condition. The MOR and MOE had achieved the standard of LY/T 1655-2006 and the surface of scrimber had natural textures which could be used as decorated materials for building.
A 3D Numerical Investigation on Droplets Distribution in a Wave-Plate Separator
Authors: Qu Yong Lei , Bu Shi , Wan Bo
Published: November 2013

The gas-liquid flow in a wave-plate separator is extremely complex due to its three-dimensional characteristic. Numerical simulation accomplished by former investigators using two-dimensional model may be appropriate for the iteration of pressure drop, but they were far from accurate in prediction of removal efficiency. To fill the gap, a three dimensional geometrical model of wave-plate separator is set up in this paper, RNG k-ε model is employed to compute the gas phase flow field, and the droplet trajectories were predicted applying the Lagrangian method. The turbulent dispersion of droplets were simulated by discrete random walk model. Using the assumption of a constant liquid loading of gas flow, simulation were accomplished for six different inlet velocities and two different droplet sizes. The influence pattern of gravity together with gas velocity on droplets distribution and the overall removal efficiencies were obtained.
Researcher on Manufacturing Surface of Air Compressor Cylinder by Vibration and Mechanism of Lubrication
Authors: Zhong Mei Peng , Yuan Ju Long , Yao Wei Feng , Chi Xiang
Published: November 2013

The method of the impacting to manufacture micro-pits is put forward in order to reduce friction between Piston ring and Cylinder liner, and improve the effective of air compressor. Method and principium of the impacting to manufacture micro-pits is recounted. The cylinder liner is set on principal axis of the rotating lathe. The tool can feed toward axis or radial direction. The micro-pits deepness is controlled by axis feeding, and distance between two micro-pits is controlled by radial feeding. The motor drives eccentricity wheel, so that the tool engender the low frequency vibration. The micro-pits are manufactured by the tools on low-frequency vibration. The effective of micro-pits processing is improved because the matrix tools were designed and manufactured. The depth of micro-pits can be controlled, so that it is even. The dynamic lubrication is built up between the cylinder and the piston, because the distributing regulation and the structural parameter can be controlled, and the micro-pits distribute evenly and independently. A theoretic model was presented to study the lubrication performance, The theory of dynamic lubrication of the honeycomb micro-pits was researched. The air compressor cylinder liners were manufactured. The tests of air compressors which cylinder liners have no micro-pits and air compressors which cylinder liners have micro-pits were done. The test result proves that friction between Piston ring and Cylinder liner is reduced, and the effective of air compressor is improved because of micro-pits.
Comparative and Study the Influence of Sand Depth for Liquefied Evaluation
Authors: Li Zhao Yan , Chen Zhuo Shi
Published: November 2013

CPT is a kind of relatively superior field test technology, which is one of important the liquefaction in-situ test at home and abroad. In 1987, China has formed the national standard CPT liquefaction evaluation method, which predominantly from 1976 Tangshan earthquake liquefaction data, and then has not been tested. Recently by the 40 CPT liquefaction field data of Bachu earthquake obtained a liquefied evaluation formula. Due to comparing the liquefied evaluation methods at home and abroad, found the national standard CPT liquefied critical curve is qualitatively distinct to the others liquefied evaluation methods. If it is wrong about the code of CPT liquefied evaluation method, which the liquefied critical curve will be smaller along with the direction of the depth, will direct the liquefied evaluation critically be conservative and the depth liquefaction evaluation clearly be hazardous. In theory, this problem can be attributed to the influence of sand depth for liquefied evaluation, worthy of further discussion.
The Component Analysis of Penetration Sealer Materials
Authors: Teng Li Wei , Lin Wei Ting , Chen Jie , Cheng An , Hsu Hui Mi
Published: November 2013

Nowadays, its more common of dispensing a topping material like concrete crystalline penetration sealer materials (CSM) onto the surface of a plastic substance such as concrete to extend its service life span by surface protections from outside breakthrough. Its known as the CSM may penetrate into the existing pores or possible cracks in such a way that it may form crystals to block the potential paths which provide breakthrough for any unknown materials. Even though all kinds of test data and researches have been reported to boast of its advantages in both theoretical technologies and application functions, to accept that as an agreed fact, namely the major components and those proportions have not been fully announced in public or research. This study employed various experiments, such as scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Fourier transform infrared spectroscopy (FT-IR), to identify key components of CSM for developing another type of CSM so that its components could be open for the public. There are two types of commercial CSM adopted for the tests and then thru a series of discusses of test results the most possible components of CSM are proposed as a future reference of CSM related researches.
Research on Surface Roughness Measurement of ACSR Using Light-Section Microscope
Authors: Hua Guang Ru , Yue Teng , Lin Ying Chao
Published: November 2013

In order to accurately measure the surface roughness of the outer strands on aluminum conductor steel reinforced cable, two different methods are proposed to correct the error by the general method using light-section microscope. Comparing the images by staining method and angle amendment method for ACSR cable, it is found that the later is better than staining methods. The result conducts that angle amendment method using light-section microscope is suitable for measuring the surface roughness of the outer strands on ACSR cable.
Reform and Practice in Major-Division Engineering Training Model Based on Project-Driven
Authors: Lv Ru Jin , Liao Wei Qi , Wang Xi She
Published: November 2013

On the basis of analyzing the current situation of engineering training in colleges, the engineering training model based on project-driven is pointed out. It is considered that constructing the course teaching system on major-division not only mobilize students innovative initiative, cultivate innovative spirit, and enhance the ability of engineering practice, but also raise training efficiency and effect by this new teaching means.
Project Teaching Reform and Practice in the Art and Design Course
Authors: Xia Zhi Liang
Published: November 2013

This paper analysed the significance of project teaching in design direction and the way to carry out,we elaborated total curriculums arrangement based on actual design case,and then put forward the theory that in the revolution theory teaching and practice should be connected. In the background of taking actual project as design practice item,expounded how to develop students’creative ability、innovative thinking ability during teaching，at last it raised solve methods for questions what we might meet during the teaching stage.
Comparison of Prediction Models for Concrete Carbonation
Authors: Yu Bo , Cheng Di , Shi Che Si , Wei Hai Xin
Published: November 2013

Three prediction models for concrete carbonation were investigated based on 79 groups accelerated carbonation data collected from the references. Model comparison and experimental verification demonstrate that the empirical models are simple and convenient for engineers, but it is often limited to the set of conditions under which they are developed. However, the theoretical model derivated from the carbonation mechanism and the mass conservation of carbonatable constituents is of good accuracy and applicability to real life scenarios.
Role of Gel Content on the Structural Changes of Masticated Natural Rubber
Authors: Nimpaiboon Adun , Amnuaypornsri Sureerut , Sakdapipanich Jitladda
Published: November 2013

In this study, natural rubber (NR) containing various amounts of gel was prepared by accelerated storage hardening to investigate the role of gel content on the structural changes of masticated NR. The NR samples containing various amounts of gel were subjected to mastication at various times, and subsequently characterized for the change of gel content, molecular weight, and Mooney viscosity to evaluate the role of gel content on these parameters. Furthermore, an oscillatory shear experiment using a strain sweep test was applied in this study to elucidate the structural changes of rubber samples after mastication. The results revealed that the Mooney viscosity was related to the percentage of gel fraction that has been proven to be the result of the interactions of proteins and phospholipids at the chain ends. The gel fraction of NR can be decomposed into a sol fraction by shear force during mastication and the mastication time for decomposition of gel relates to the initial gel content of the rubber. After mastication for 15 min, although the gel fraction of NR can be decomposed to ~0% w/w, the interactions of proteins and phospholipids at the chain ends still existed, and their quantities is corresponded to the gel content of raw rubber.
Application of Macca Charcoal in Saponified Natural Rubber Composites
Authors: Rodgerd Phawasoot , Yakkul Sutaporn , Sakdapipanich Jitladda
Published: November 2013

This present work is an attempt to study the composite between natural rubber (NR) and Macca charcoal, as a special additive, for producing the adhesive plaster for pain relief. The NR latex used in this work was a saponified NR (SPNR) cured by peroxide to avoid allergenic problems in human use, which causes by protein and accelerator in sulphur cure. Macca charcoal is proved to have ability to generate far infrared rays (FIR) in the range of 6-14 µm which can transfer to be heat energy. The human body can absorb FIR in this range because of their deep penetrating ability. Light energy is changed to thermal energy when FIR penetrates through skin to the subcutaneous tissues. This thermal energy helps to decrease the symptoms of stress and fatigue such as headaches, joint pain, burns, muscle spasms, and insomnia. In this work, the SPNR/Macca composite was subjected to studying the effect of Macca charcoal content on the physical and thermal properties of SPNR composites. The results showed that hardness and tensile properties increased with increasing an addition of Macca charcoal in SPNR. In addition, the increasing of Macca charcoal content enhance thermal retention estimation and thermal intensity, but has no substantial effect on depth of FIR diffusion on pork layer. Thus, SPNR/Macca charcoal composites can be an optional material apply for an adhesive bandage for pain relief purpose.
Pseudolatex from STR 5L Block Rubber for Drug Delivery
Authors: Boonme Prapaporn , Panrat Kamon , Pichayakorn Wiwat
Published: November 2013

Pseudolatex is colloidal dispersion containing spherical solid or semisolid particles and can be prepared from any existing thermoplastic water-insoluble polymers. It is useful for drug encapsulation and controlled drug release. In this study, pseudolatex base was prepared from STR 5L block rubber. The various parameters such as speed and time of homogenization, type and concentration of surfactants, amount of mineral oil, and type of drug loading were studied to prepare the stable pseudolatex. These preparations were evaluated in particle size, pH, viscosity, emulsion stability, drug encapsulation, and in vitro drug release. It was found that the most stable formulation contained 3.5% block rubber, 0.2% methyl cellulose, 6% mineral oil, 4% dibutyl phthalate, 2% sodium lauryl sulfate, and 2% Uniphen P-23 using the speed and time of homogenizer as 20000 rpm and 20 minutes, respectively. Furthermore, the pseudolatex bases reduced the protein impurity form 0.5516% to 0.2108% in formulation with mineral oil and to 0.1781% in formulation without mineral oil, that could decrease contact allergy caused by the protein allergens. Dichloromethane residues in pseudolatex bases were 22.05 mg/L and 7.85 mg/L in formulations with and without mineral oil, respectively, that were satisfied from USP recommendation value of lower than 600 mg/L. Propranolol HCl, lidocaine HCl, and indomethacin could be loaded into pseudolatex only in the concentration of 1%. However, lidocaine base in the concentration of 1-5% could be loaded into pseudolatex which had the similar physical properties and stability to pseudolatex base. The in vitro drug release from pseudolatexs provided the controlled drug release for more than 24 hr.
Morphology Development in Thermoplastic Vulcanizates (TPV)
Authors: Cassagnau Philippe , Barres C. , Martin G. , Garois N. , Sonntag Ph.
Published: November 2013

The mechanisms of fragmentation and dispersion in molten polypropylene (PP) of several pre-crosslinked and plasticized ethylene-propylene-diene terpolymer (EPDM) networks were studied. The results highlight the importance of the gel fraction of the pre-crosslinked EPDMs on the quality of the dispersion of such networks. As a result, pre-crosslinked EPDM having a gel fraction below gEPDM=0.7 can be finely and homogeneously fragmented and dispersed in presence of PP. Nevertheless, contrarily to some theoretical model expectations, a partial fragmentation of the chemical networks was always observed even at very high crosslink density (gEPDM>0.7). It can be then admitted a collisioncoalescenceseparation type erosion mechanism of the EPDM domains. Finally, these results brought significant information on TPV morphology stabilization and their related mechanical properties.
ECO-Adhesive from Modified Natural Rubber for Wood Applications
Authors: Suchat Sunisa , Yingprasert Wisanee
Published: November 2013

Both commercial entities and the government have expressed interest in safe and environ-mentally friendly adhesives, ECO-adhesives, containing no volatile harmful or toxic chemicals. In the wood industries, currently common adhesives such as urea formaldehyde (UF), phenol formaldehyde (PF) release formaldehyde vapors that are a human health concern, with unpleasant odor. We examined the potential of modified natural rubber latexes (MNRL) for use as ECO-adhesives. Three latex types were used, namely epoxidized natural rubber (ENR), liquid natural rubber (LNR), and NR/PMMA blend. The MNRL was characterized by FT-IR, NMR, and GPC. The proportion of tackifying agent to the dry weight of latex was varied in the range 0 to 60 phr. It was found that the MNRL uniformly mixed in the latex form. All MNRL adhesives would have passed the Thai standard for rubber-based adhesives, based on their: total solids content (TSC), pH, viscosity, shear strength, and emissions of formaldehyde. Up to 30% fraction of tackifying agent, tack and shear strength increased with its content. Compared to a commercial UF adhesive, the MNRL had lower emissions of formaldehyde vapors, lower shear strength, but higher TSC, and higher viscosity. In summary, for select wood applications with moderate bond shear demands, these new rubber based adhesives could provide a health conscious and non-toxic alternative, with the further advantage of low odor.
Fabrication and Characterization of Epoxidized Natural Rubber-Chitosan Membrane
Authors: Taweepreda Wirach , Wichianchom Anuchit
Published: November 2013

The membranes obtained from the mixtures of epoxidized natural rubber latex (ENR) and chitosan solution were prepared and characterized. The chemical structure of the membrane was confirmed by ATR-FT-IR spectroscopy and found the peak at 1315 and 1155 cm-1 indicated ether linkage was formed between epoxide group and chitosan corresponding with an enhancement of their mechanical properties which were observed using dynamic mechanical thermal analysis (DMTA). The dielectric properties and ionic conductivity of membrane were investigated using LCR meter and found that the ionic conductivity was increased with increasing the chitosan content.
Kinetic and Nanomechanical Study of Poly (3-hydroxybutyrate)-Epoxidized Natural Rubber-Organomodified Montmorillonite Nanohybrids
Authors: Salehabadi Ali , Bakar Mohamad Abu
Published: November 2013

Multicomponent systems, consisting two immiscible polymers, Poly (3-hydroxybutyrate) (PHB) and 50 mol% epoxidized natural rubber (ENR-50) and a filler i.e. organomodified montmorillonite (MMT) have been prepared by solvent casting technique. A 50/50 composition of PHB, a biodegradable polymer, and ENR-50 was first dissolved in chloroform and this was followed by the addition of 1, 3 or 5 wt% MMT to form the nanohybrid samples. The kinetic and nanomechanical properties of the as prepared samples were studied. Kissinger plots showed that the nanohybrids exhibited a decrease in degradation activation energy (Ed) as MMT content was increased. The nanomechnical study of these samples indicates an increase in hardness (H) and elastic modulus (E) when MMT content is increased in the samples.
Influence of N-Phenyl-p-Phenylenediamine Modified Epoxidized Palm Oil on Properties of Carbon Black Filled Natural Rubber Compound and Vulcanizate
Authors: Ieadsang Supaporn , Thitithammawong Anoma , Nakason Charoen , Kaesaman Azizon
Published: November 2013

Modified epoxidized palm oil (pA-m-EPO) was prepared by a reaction of epoxidized palm oil (EPO) with n-phenyl-p-phenylenediamine. Chemical structure of the pA-m-EPO was characterized by using FT-IR spectrophotometer. Influence of the pA-m-EPO on bound rubber content, total mixing energy, Mooney viscosity and curing characteristics of carbon black filled natural rubber compound together with mechanical and morphological properties of carbon black filled natural rubber vulcanizates was later studied. Results showed that the NR compound and vulcanizate with using the pA-m-EPO gave inferior properties than those of using the aromatic oil. However, they provided better properties than those of the treated distillate aromatic extract (TDAE) excepting filler dispersion. Furthermore, the pA-m-EPO can be claimed as non-carcinogenic processing oil with low polycyclic aromatic hydrocarbons.
Resilience of Rubber-Based Intercropping System in Southern Thailand
Authors: Jongrungrot Vichot , Thungwa Somyot
Published: November 2013

Many farmers have understood and had direct experience with resilience in a rubber-based intercropping system under risks and uncertainties of world economy and government policies. However, quantitative studies to examine and confirm such results are still limited.This study found some hidden values of economic resilience in the rubber-based intercropping system which could be of great use to future agricultural development. Results were drawn from 5 rubber-based intercropping plots in Southern Thailand by building three scenarios: 1) rubber price during 2017-2021 is lower; 2) wage of farm labor during 2013-2021 is higher; and 3) farmers reduce risks and uncertainties by cutting intercropped timber and/or selling products from rubber-based intercrops. Results show that 3 plots will have a high level of resilience of margin (income from plots after deducting operation cost) while one plot will have a medium level and another will have a low level. Main factors affecting resilience levels will be: quantities and kinds of intercropped timber, appropriate cutting period of timber, efficiency in plot management by farmers to increase yields of intercropped fruit trees, and adaptation of other kinds of products in the plots to increase household income. High proportion of off-farm income will also be useful in reducing some negative effects from lower rubber priceand higher wage of farm labor.
Optimization of Epoxidation Degree and Silane Coupling Agent Content for Silica-Filled Epoxidized Natural Rubber Tire Tread Compounds
Authors: Kaewsakul Wisut , Sahakaro Kannika , Dierkes Wilma , Noordermeer Jacques W.M.
Published: November 2013

Parallel studies on the influence of epoxide contents in epoxidized natural rubbers (ENRs) in the absence of bis-(triethoxysilylpropyl) tetrasulfide (TESPT) coupling agent, as well as a combination of ENRs with different loadings of TESPT on the properties of ENR compounds, are carried out in this work. The results suggests that the best possible combination to optimize processibility and to improve reinforcement efficiency is to utilize ENR with an epoxide content in the range of 20 30 mol%, together with 2 4 wt% relative to the silica content of TESPT. This leads to a reduction of TESPT when compared to the conventional natural rubber compounds.
Silica-Reinforced Natural Rubber Compounds Compatibilized through the Use of Epoxide Functional Groups and TESPT Combination
Authors: Sengloyluan Karnda , Sahakaro Kannika , Noordermeer Jacques W.M.
Published: November 2013

Epoxidized natural rubber (ENR) and bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) were used to improve the properties of silica-filled NR. The use of ENR containing 51 mol% epoxide groups (ENR-51) as a compatibilizer without TESPT was optimized at 7.5 phr, based on the results of Payne effect and tensile strength. By using 7.5 phr of ENR-51 with varying amounts of TESPT in a range of 2 to 5 wt% relative to the silica, the properties of compounds were compared to those of the ones with optimum TESPT content (i.e. 8.6 wt% relative to the silica) and without. The addition of TESPT to the ENR-51 compatibilized silica-filled NR compound had no effect on Mooney viscosity but lowered the Payne effect to the same level as that of the silica/TESPT compound, and significantly decreased both scorch and optimum cure times. The silica-filled NR with ENR and the small amount of TESPT combination showed a further increase in tensile strength to match that of the optimized silica/TESPT system, while maintained the elongation at break. This work demonstrates that the use of ENR as compatibilizer clearly enhances the properties of silica-filled NR compounds, and that such properties can be further improved by adding TESPT at a half or less amount of TESPT normally needed for silica-filled compounds.
The Effect of Kaolin Clay on Fire Retardancy and Thermal Degradation of Intumescent Flame Retardant (IFR)/Natural Rubber Composite
Authors: Thuechart Thiranan , Keawwattana Wirunya
Published: November 2013

Study the effect of kaolin clay as a synergistic agent on flame retardancy and thermal degradation in natural rubber based on intumescent flame retardant (IFR); consisting of ammonium polyphosphate (APP) as acid source, pentaerythritol (PER) as a carbonization agent and melamine (ME) as a blowing agent was undertaken. The intumescent was examined at different loading (60, 80 and 100 phr). Kaolin clay was incorporated into flame retardant at four different concentrations (0.5, 1.0, 1.5 and 2.0 wt% of flame retardant) to investigate the synergism between the flame retardant materials. The flammability and thermal degradation of composites were characterized by UL-94 rating (vertical burning) test, cone calorimeter (CONE) and thermogravimetric analysis (TGA). All composites could meet the UL94V-0 standard. A synergist effect was observed when kaolin clay is used in combination with the intumescent flame-retardant through the TGA and CONE results. Moreover Scanning Electron Microscope (SEM) was done for the char morphology.
Role of Hydroxyl-Terminated Polybutadiene in Changing Properties of EPDM/ENR Blends
Authors: Prasertsri Sarawut , Amnuay Passakorn , Sripan Khanitta , Nuinu Pranee
Published: November 2013

In this research, the effect of hydroxyl-terminated polybutadiene (HTPB) on processability, mechanical properties, thermal aging and oil resistance of 80/20 ethylene-propylene diene rubber/epoxidized natural rubber (EPDM/ENR) blend was investigated. The amount of HTPB used was varied from 0-4 parts per hundred of rubber (phr). The results revealed that addition of HTPB into EPDM/ENR blend decreased the compound viscosity, while scorch time and cure time slightly increased with increasing HTPB content. Furthermore, hardness, tensile and tear strengths of the blend decreased due to the poor dispersion of fillers in the presence of HTPB. After thermal aging treatment, the crosslink density of all EPDM/ENR blends increased leading to increasing in 100% modulus, tensile strength and swelling resistance, as well as reducing in elongation at break. However, it had additional plus features that high resilience with low compression set was achieved in the blend containing 2 phr of HTPB.
Room-Temperature Curing Adhesive Based on Graft Copolymers of Natural Rubber and Poly(diacetone acrylamide)
Authors: Thongnuanchan Bencha , Ninjan Rattanawadee , Bunsanong Anchisa , Nakason Charoen
Published: November 2013

Natural rubber latex grafted with poly(diacetone acrylamide), NR-g-PDAAM, was prepared with different weight ratios of NR/DAAM (i.e., 90/10, 95/5, and 97.5/2.5) by seeded emulsion polymerization at 50°C. The redox-initiation system, cumene hydroperoxide (CHP) and tetraethylene pentamine (TEPA), was used to initiate the polymerization. The results indicate that increasing of monomer concentrations led to a slight increase in the percentage conversion whereas the grafting efficiency of NR-g-PDAAM was not affected significantly. The chemical structure of the synthesized graft copolymers was confirmed by FTIR technique and the NR-g-PDAAM prepared using a NR/DAAM weight ratio of 95/5 was selected for the further preparation of adhesives. The feasibility of using adipic acid dihydrazide (ADH) as crosslinker for NR-g-PDAAM adhesives at room temperature was then investigated. An increase in the shear strength of the adhesive was observed with the addition of ADH. Additionally, an increase in the level of ADH crosslinker also resulted in a marked increase in the adhesion strength of adhesive. Based on these observations, it can be concluded that ADH is an effective crosslinker for NR-g-PDAAM based adhesive.
Influence of Non-Rubber Components on NR Surface Modification by Chlorination
Authors: Vallat Marie France , Radabutra Siriwat , Thanawan Sombat , Bresson Bruno , Chollakup Rungsima , Rungsanthien Kanokwan , Suwanruji P. , Klanarong Sriroth , Smitthipong Wirasak , Mougin Karine
Published: November 2013

Natural rubber (NR) is a very useful elastomer and renewable polymer with outstanding properties compared to synthetic elastomers. However, as a natural polymer, the non-rubber species (proteins, phospholipids, carbohydrate, etc.) have to be considered carefully for the understanding of the surface and interfacial properties. Especially these components can markedly affect the frictional and adhesive properties of the rubber surface. Although many methods can be used to modify the surface properties, chlorination remains one of the easiest way.The present study deals with surface modification of peroxide crosslinked NRs and synthetic cis-1,4 polysioprene as reference samples by chlorination. Surface and frictional properties of these different rubbers were analyzed by various complementary techniques The influence of critical parameters on wetting, frictional and mechanical properties were investigated and will be discussed