Thermal Conductivity of Elastomer Vulcanizates by Differential Scanning Calorimetry

1982 ◽  
Vol 55 (1) ◽  
pp. 191-207 ◽  
Author(s):  
Anil K. Sircar ◽  
John L. Wells
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Carbon Black ◽  
Polymeric Materials ◽  
High Concentration ◽  
Scanning Calorimetry ◽  
Relationship Of ◽  
Particle Size And Structure ◽  
Thermal Conductivity Λ ◽  
Very High

Abstract A du Pont 990 differential scanning calorimeter was modified to measure thermal conductivity of elastomer vulcanizates. The method is quick and reproducible and is recommended for scouting research of polymeric materials. The thermal conductivity λ values obtained by this method of some known materials compare favorably with those in the literature. Carbon black increases λ values in all elastomers. Particle size and structure of carbon black seem to affect λ values erratically, although the trend is towards higher λ values with larger particle size and higher structure. A linear relationship of λ vs. volume concentration of carbon blacks and other fillers is observed, except at a very high concentration. The extrapolated values of λ for a filler differ in different elastomeric media. Noncompatible elastomer blends increase or decrease λ values according to the nature and proportion of elastomers. The effect of the manner of addition of carbon black does not seem to affect the λ value of compatible blends. Higher temperatures decrease λ values for all the vulcanizates studied.

Research of Thermal Conductivity and Tensile Strength of Carbon Black-Filled Nature Rubber

2009 ◽  
Vol 87-88 ◽  
pp. 200-205 ◽  
Author(s):  
Yan He ◽  
Zhong Yin ◽  
Lian Xiang Ma ◽  
Jun Ping Song
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Volume Fraction ◽  
Carbon Black Particle ◽  
Black Particle ◽  
The Difference ◽  
Thermal Conductivities

Through measuring the thermal conductivities and tensile strength of nature rubbers filled with carbon black and comparing with each other, it is shown that the difference of carbon black particle size and the structure affects on the thermal conductivity and tensile strength of nature rubber. Thermal conductivities of carbon black-filled nature rubber are enhanced with the increase of volume fraction of filler; tensile strength of composite increases first and then decreases with the increase of carbon black volume fraction.

Determination of Carbon Black Type in Filled Rubber Vulcanizates

1967 ◽  
Vol 40 (5) ◽  
pp. 1323-1329 ◽  
Author(s):  
Lester G. Nabors ◽  
Merton L. Studebaker
Keyword(s):  
Particle Size ◽  
Carbon Black ◽  
Filled Rubber ◽  
Vacuum Pyrolysis ◽  
Acid Washing ◽  
Analogous Data ◽  
Particle Size And Structure ◽  
Qualitative Analyses ◽  
Size And Structure

Abstract A system of analysis has been described which permits determining the type of rubber grade carbon black in a vulcanizate. The carbon black is removed from the vulcanizate by vacuum pyrolysis at 850° C and its reflectance after acid washing and compression at 15,000 psi and apparent specific volume at 703 psi are determined. These measurements permit estimation of particle size and “structure.” Supplementary analyses are required for channel blacks. The procedure is most precise when the analytical values are compared with analogous data obtained from carbon blacks of known properties when removed by the same procedure from similar vulcanizates. As in all qualitative analyses, the more information which is available to the analyst, the more reliably he is able to interpret his results.

scholarly journals Achieving High Thermal Conductivity in Epoxy Composites: Effect of Boron Nitride Particle Size and Matrix-Filler Interface

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1156 ◽  
Author(s):  
Sasan Moradi ◽  
Yolanda Calventus ◽  
Frida Román ◽  
John M Hutchinson
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Boron Nitride ◽  
Reaction Kinetics ◽  
Heat Of Reaction ◽  
Scanning Calorimetry ◽  
Base Interaction ◽  
Cure Reaction ◽  
Thermally Conducting ◽  
Nitride Particle

For the thermal management of high watt density circuit layers, it is common to use a filled epoxy system to provide an electrically insulating but thermally conducting bond to a metal substrate. An epoxy-thiol system filled with boron nitride (BN), in the form of 2, 30 and 180 µm platelets, has been investigated with a view to achieving enhanced thermal conductivity. The effect of BN content on the cure reaction kinetics has been studied by differential scanning calorimetry and the thermal conductivity of the cured samples has been measured by the Transient Hot Bridge method. The heat of reaction and the glass transition temperature of the fully cured samples are both independent of the BN content, but the cure reaction kinetics is systematically affected by both BN content and particle size. These results can be correlated with the thermal conductivity of the cured systems, which is found to increase with both BN content and particle size. For a given BN content, the thermal conductivity found here is significantly higher than most others reported in the literature; this effect is attributed to a Lewis acid-base interaction between filler and matrix.

scholarly journals Experimental Investigation of Thermal Conductivity and Specific Heat of the Calcium Phosphate Ore for a Drying Application

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhor El Hallaoui ◽  
T. Moudakkar ◽  
S. Vaudreuil ◽  
T. Bounahmidi ◽  
S. Abderafi
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Particle Size ◽  
Moisture Content ◽  
Specific Heat ◽  
Regression Models ◽  
Average Error ◽  
Scanning Calorimetry ◽  
Temperature Estimation ◽  
Modulated Differential Scanning Calorimetry

This paper discusses an experimental investigation to determine regression models for thermal properties of phosphate particles and to analyze the performances of the phosphate flash dryer. For this purpose, the specific heat capacity and thermal conductivity of phosphate particles were experimentally determined by the modulated differential scanning calorimetry (MDSC) and the modified transient plane source method (MTPS), respectively. Multiple regression models were developed to correlate the specific heat and thermal conductivity to moisture content, particle size, and temperature. Experimental results showed that the measured thermal conductivity and dry specific heat were found in the range of 0.07–0.61 W/m K and 510–630 J/kg·K, respectively. Furthermore, the specific heat increased almost linearly with temperature but decreased with particle size, while the thermal conductivity increased with moisture content and temperature but decreased with particle size. These correlations were integrated to the phosphate flash dryer mathematical model and used to analyze the thermal behavior of phosphate drying. Simulation results were compared to experimental data obtained on a bench-scale dryer, where the model exhibits an average error of 2% and 4% for moisture content and air temperature estimation, showing good fitting for practical data.

DISCUSSION ABOUT THERMAL CONDUCTIVITY OF CARBON BLACK FILLED RUBBER

2015 ◽  
Vol 6 (2) ◽  
pp. 159-172 ◽  
Author(s):  
Junping Song ◽  
Lianxiang Ma ◽  
Yan He ◽  
Wei Li ◽  
Shi-Chune Yao
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Filled Rubber

Thermal Conductivity of Fly Ash Cenospheres for Variable Particle Size Ranges

2016 ◽  
Vol 4 (2) ◽  
pp. 19
Author(s):  
MENEZES CRAIG ◽  
RATHOD AJIT P ◽  
WASEWAR KAILAS L. ◽  
◽  
◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Fly Ash ◽  
Fly Ash Cenospheres

Optimasi Proses Pembuatan dan Karakterisasi Fisik Niosom Sinkonin

2019 ◽  
Vol 16 (2) ◽  
pp. 178
Author(s):  
Hariyanti Hariyanti ◽  
Sophi Damayanti ◽  
Sasanti Tarini
Keyword(s):  
Differential Scanning Calorimetry ◽  
Particle Size ◽  
Hair Follicle ◽  
Scanning Calorimetry ◽  
Span 60

Sinkonin praktis tidak larut dalam air, sedikit larut dalam kloroform dan alkohol. Hal ini berdampak pada rendahnya penetrasi transfollicular sinkonin, karena hanya bahan aktif hidrofilik yang mampu melewati hair follicle. Dengan demikian dibutuhkan satu sistem penghantaran yang mampu menurunkan hidrofobisitas sinkonin untuk meningkatkan penetrasi sinkonin ke follicle. Niosom merupakan vesikel ampifilik dengan struktur lapisan rangkap yang terbentuk dari hidrasi kombinasi surfaktan nonionik dan kolesterol yang mampu menurunkan hidrofobisitas sinkonin. Penelitian ini bertujuan untuk menentukan proses pembuatan niosom sinkonin yang optimum. Pembuatan niosom sinkonin diawali dengan menentukan temperatur gelasi (Tg) dari span 60 dengan Differential Scanning Calorimetry (DSC), kemudian dilanjutkan dengan optimasi proses meliputi: optimasi kecepatan rotavapor pembentukan film lapis tipis, temperatur hidrasi, kecepatan rotavapor hidrasi, waktu hidrasi, dan waktu sonikasi. Karakteristik vesikel niosom yang optimal meliputi: ukuran partikel dan indeks polidispersitas dengan menggunakan Particle Size Analized (PSA) serta efisiensi penjeratan sinkonin dengan menggunakan KCKT. Temperatur gelasi (Tg) span 60 45±2 oC, kecepatan rotavapor pembentukan film lapis tipis niosom 210 rpm, temperatur hidrasi 55±2 oC, kecepatan rotavapor hidrasi 210 rpm, waktu hidrasi 20 menit, waktu sonikasi suspensi niosom 1 menit. Ukuran vesikel yang diperoleh adalah 100–200 nm, indeks polidispersitas 0,2–0,4 dan efisiensi penjeratan niosom sinkonin 84,49±0,0025%. Proses pembuatan niosom sinkonin memiliki pengaruh besar terhadap hasil ukuran vesikel dan efisiensi penjeratan niosom sinkonin.

Ground water quality of selected areas of Punjab and Sind Provinces, Pakistan: Chemical and microbiological aspects

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Ionic Concentration ◽  
Chloride Ions ◽  
Potassium Ions ◽  
Ammonium Ions ◽  
High Concentration ◽  
Phosphate Ions ◽  
Sodium Magnesium ◽  
Very High ◽  
Microbiological Aspects

The assessment of groundwater is essential for the estimation of suitability of water for safe use. An attempt has been made to study the groundwater of selected areas of Punjab (Sheikhupura & Sahiwal) and Sindh (Sindh, Jawar Dharki and Dharki), Pakistan. The results indicate that pH, color and odor were all within limits of WHO that is pH ranges 6.5–8.5, colorless and odorless, respectively. The high values of suspended solids were observed in the Sindh-1 and Dharki samples. Microbiologically only Sahiwal and Jawar Dharki were found fit for drinking purpose. Trace metals analysis of Sheikhupura-1 and Sindh-1 showed that values do not fall within limits of WHO for Iron. The ionic concentration analysis showed that high bicarbonate (HCO3-), ions are present in the samples of Sahiwal and Dharki; Sindh-1 and Jawar Dharki samples showed very high concentration for chloride ions, all samples were satisfactory level for sulphate (SO42-), sodium, magnesium and phosphate ions except samples of Sindh-1 and Jawar Dharki. High concentration of calcium and potassium ions was observed in samples of Sindh-1, while all other samples were found fit for drinking purposes in respect of nitrate, nitrite and ammonium ions. The high concentration of Fluoride was found only in Sheikhupura-2 samples.

WIELAND-K88

Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Relaxation ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Relaxation Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.

Crystal Transition and Drug-excipient Compatibility of Clarithromycin in Sustained Release Tablets

2020 ◽  
Vol 16 (7) ◽  
pp. 950-959
Author(s):  
Yu Li ◽  
Xiangwen Kong ◽  
Fan Hu
Keyword(s):  
Sustained Release ◽  
Powder Diffraction ◽  
Magnesium Stearate ◽  
Influential Factor ◽  
High Concentration ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sustained Release Tablets ◽  
Crystal Transition ◽  
Excipient Compatibility

Background: Clarithromycin is widely used for infections of helicobacter pylori. Clarithromycin belongs to polymorphic drug. Crystalline state changes of clarithromycin in sustained release tablets were found. Objective: The aim of this study was to find the influential factor of the crystal transition of clarithromycin in preparation process of sustained-release tablets and to investigate the possible interactions between the clarithromycin and pharmaceutical excipients. Methods and Results: The crystal transition of active pharmaceuticals ingredients from form II to form I in portion in clarithromycin sustained release tablets were confirmed by x-ray powder diffraction. The techniques including differential scanning calorimetry and infrared spectroscopy, x-ray powder diffraction were used for assessing the compatibility between clarithromycin and several excipients as magnesium stearate, lactose, sodium carboxymethyl cellulose, polyvinyl-pyrrolidone K-30 and microcrystalline cellulose. All of these methods showed compatibilities between clarithromycin and the selected excipients. Alcohol prescription simulation was also done, which showed incompatibility between clarithromycin and concentration alcohol. Conclusion: It was confirmed that the reason for the incompatibility of clarithromycin with high concentration of alcohol was crystal transition.

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