Relation of Volume Change to the Mechanism of Rubber Vulcanization

1934 ◽  
Vol 7 (4) ◽  
pp. 693-699
Author(s):  
Ira Williams
Keyword(s):  
Physical Properties ◽  
Volume Change ◽  
Physical State ◽  
Direct Relation ◽  
Polymeric State ◽  
Primary Valence

Abstract The present investigation shows that no direct relation exists between either combined sulfur or density and the degree of vulcanization. It is not probable that the various changes in physical properties of the rubber during vulcanization are due to changes in the polymeric state involving a change in primary valence forces. Neither is it apparent in what manner combination of sulfur has contributed directly to the change in physical properties of the rubber. It is probable that the change in physical state is due to a change in manner or degree of aggregation of the rubber molecules.

Effects of boric acid addition and sintering temperature on the thermal conductivity of perlitebased insulation materials

2020 ◽  
Vol 62 (4) ◽  
pp. 408-412
Author(s):  
Yuksel Palaci
Keyword(s):  
Thermal Conductivity ◽  
Physical Properties ◽  
Boric Acid ◽  
Thermal Insulation ◽  
Sintering Temperature ◽  
Direct Relation ◽  
Insulation Materials ◽  
Acid Addition ◽  
Composition Characteristics

Abstract In this study, the variation of thermal conductivity and density of 15 wt.-% boric acid - 85 wt.-% sepiolite, 30 wt.-% boric acid - 30 wt.-% sepiolite - 40 wt.-% perlite, 30 wt.-% boric acid - 30 wt.-% cordierite - 40 wt.-% perlite and 30 wt.-% boric acid - 30 wt.-% alumina - 40 wt.-% perlite compositions at 700 °C and 900 °C sintering temperatures were investigated. The results show that increasing the amount of boric acid and decreasing the sintering temperature lead to an improvement in thermal insulation properties. There is a direct relation between the thermal conductivity and density of the specimens. Both physical properties change with a change in the sintering temperature and the composition characteristics. Minimum thermal conductivity has been observed in a specimen consisting of 30 wt.-% boric acid - 30 wt.-% alumina - 40 wt.-% perlite.

The Distribution of Combined Sulfur in Vulcanized Rubber and Its Bearing on the Sulfide Linkage Theory of Vulcanization

1939 ◽  
Vol 12 (2) ◽  
pp. 191-199
Author(s):  
I. Williams
Keyword(s):  
Physical Properties ◽  
Direct Evidence ◽  
Cross Linking ◽  
Direct Relation ◽  
Vulcanized Rubber ◽  
Free Sulfur

Abstract No direct evidence exists to support the sulfide linkage theory of vulcanization, which assumes that cross-linking of the molecules with sulfur would retain the elasticity and decrease the plasticity of the rubber. The following facts do not favor the sulfide linkage theory of vulcanization : (1) Vulcanized rubber can be peptized under conditions which do not appear to rupture a sulfide linkage. (2) No direct relation exists between the physical properties of vulcanized rubber and the amount of combined sulfur. (3) No direct relation exists between the ease of peptization and the physical properties of the vulcanizate. (4) Combined sulfur appears to assist the solvation of rubber. Rubber vulcanized with thiuram disulfides in the absence of free sulfur has poor physical properties but peptizes with difficulty. An increase in combined sulfur without a corresponding improvement in physical properties assists solvation. (5) Rubber having the best physical properties is also the most heterogeneous with respect to sulfur. The sulfide linkage theory would suggest that an even distribution of sulfur would produce the best physical properties. (6) Fractions of peptized vulcanizates, on evaporation of their solutions, leave insoluble vulcanized films, which shows that linkage by means of primary forces is unnecessary for producing the vulcanized condition.

Study on Physics Properties of ESPCP Stator Rubber with Oil Erosion

2011 ◽  
Vol 230-232 ◽  
pp. 987-991 ◽  
Author(s):  
Zhong Feng Guo ◽  
Shi Jie Wang ◽  
Lei Wang ◽  
Yi Zhang ◽  
Zhong Wei Ren
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Crude Oil ◽  
Volume Change ◽  
Elongation Rate ◽  
Operating Conditions ◽  
Rate Change ◽  
Butadiene Rubber ◽  
Submersible Motor ◽  
Variation Rule

For studying physical properties of Nitrile Butadiene Rubber(NBR) stator of Electrical Submersible-motor-driven Progressive Cavity Pumping (ESPCP) with oil erosion, two different formulations of NBR soaked in crude oil at 90 °C for 168h. Variation rule with time of rubber quality, hardness, volume, tensile strength and elongation rate are got. The results show that erosion in the same temperature, rubber quality increase rapidly in the first 24h, increase slowly down in 24~168h. Rubber hardness does not change significantly soaked within 168h. Rubber volume change obviously in the first 72h and change slowly in 72~168h. In the first 96h, the rubber's tensile strength and elongation rate change quickly, slowly changes in 96~168h. The study has a certain reference of design of ESPCP stator under certain operating conditions.

scholarly journals Ecologization of physical condition of Precarpathian soils

2013 ◽  
pp. 309-316
Author(s):  
Pavlo Romaniv
Keyword(s):  
Physical Properties ◽  
Key Words ◽  
Monitoring System ◽  
Physical Condition ◽  
Human Subject ◽  
Physical State ◽  
Agricultural Use

Last update importance of the study of the physical condition of soils Precarpathians. It was found that the physical properties of soils are among the earliest human subject affected by agricultural use. These theoretical and practical areas as greening research, optimization of the use should be of paramount importance in the monitoring system of soil Ukraine. Key words: physical state of the soils, Precarpathians, ecology, soils monitoring.

scholarly journals Electrolytes and colloids.—The physical state of gluten

1909 ◽  
Vol 81 (545) ◽  
pp. 38-43 ◽  
Keyword(s):  
Physical Properties ◽  
Wheat Flour ◽  
Total Protein ◽  
Physical State ◽  
Tap Water

Gluten, as ordinarily prepared by washing wheat flour in tap water, forms a coherent stringy mass insoluble in water. It consists essentially of a mixture of two proteins, gliadin and glutenin, but even when very thoroughly washed it always includes some starch. Gliadin, which forms rather more than half of the total protein, is soluble in dilute alcohol, and gives to the gluten its peculiar physical properties. The power which dough possesses of retaining the gas formed during fermentation is due to the tenacity and ductility of gluten. Therefore, the property of forming a light and well-shaped loaf, which is so variable a feature of different flours, is determined by the amount and the physical state of the contained gluten.

Radio Emission of the Moon, its Physical State, and the Nature of its Surface

1962 ◽  
Vol 14 ◽  
pp. 475-489 ◽  
Author(s):  
V. S. Troitsky
Keyword(s):  
Experimental Data ◽  
Radio Emission ◽  
Physical Properties ◽  
Physical State ◽  
Single Layer ◽  
Thermal Conditions ◽  
Homogeneous Structure ◽  
The Moon ◽  
Lunar Material

Recently experimental data have been obtained on lunar radio emission which enable one to solve the problem as to which model of structure for its upper layer corresponds to reality: single layer (homogeneous structure of the covering) or a widely distributed two-layer-dust cover [1]. They also enable one to draw more definite conclusions as to the physical properties, thermal conditions, and structure of lunar material.

WANDO

Alloy Digest ◽  
1979 ◽  
Vol 28 (10) ◽  
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Volume Change ◽  
Heat Treating ◽  
General Purpose ◽  
Minimum Volume ◽  
Tool Steels ◽  
Die Steel

Abstract WANDO belongs to that class of oil-hardening tool steels known as non-deforming steels. It will develop full hardness on oil quenching from a relatively low temperature with minimum volume change, hence non-deforming. It is a general-purpose tool and die steel. Among its many applications are dies for many purposes, shear blades, taps and reamers. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: TS-354. Producer or source: Cyclops Corporation.

Volume Change of Limestone and its Effects on Drying Shrinkage of Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 738-741
Author(s):  
Shogo Yagi ◽  
Carlos Aquino ◽  
Masumi Inoue ◽  
Takahisa Okamoto
Keyword(s):  
Physical Properties ◽  
Construction Industry ◽  
Volume Change ◽  
Drying Shrinkage ◽  
Limestone Aggregate ◽  
Coarse Aggregates

Recently, the cracks of concrete by drying shrinkage become one of the problems in the construction industry in Japan. The drying shrinkage decreases when the concrete is produced with limestone aggregate. However, it is not clear why the drying shrinkage is decreased. The purpose of this study is to clarify the relation between the drying shrinkage of concrete and the limestone aggregate. In this study, the experiments about the strength, elasticity and drying shrinkage of concrete and the physical properties and shrinkage of coarse aggregates were conducted. It is thought that the volume change of aggregates affects directly the drying shrinkage in concrete.

scholarly journals Effects of Epoxidised Natural Rubber on the Oil Resistance Property of NBR/ENR Blends used for Safety Footwear Application

2019 ◽  
Vol 7 (4.14) ◽  
pp. 322
Author(s):  
H. Mohd Hanif ◽  
K. C. Yong
Keyword(s):  
Natural Rubber ◽  
Physical Properties ◽  
Tensile Properties ◽  
Volume Change ◽  
Abrasion Resistance ◽  
Sustainable Material ◽  
Oil Resistance ◽  
Abrasion Loss ◽  
Resistance Property ◽  
Footwear Industry

Epoxidised natural rubber, ENR has emerged as a sustainable material for many applications due to its unique properties. This study sets out to investigate the effects of ENR on the oil resistance property of nitrile rubber, NBR composites used for safety footwear application. Blends of NBR/ENR i.e. 100/0, 90/10, 80/20, 70/30, 60/40 and 50/50 were prepared and tested for their oil resistance property and other physical properties such as hardness, tensile properties and abrasion loss. Results showed that varying the amount of ENR did not significantly affect the hardness and tensile properties of the composites. Nonetheless, it was found that ENR content highly influences the abrasion loss of the composites in which the abrasion resistance decreased with further addition of ENR contents. Despite the increase in oil swelling of the composites with increasing ENR content, the oil swelling values are considered low (< 5% volume change), indicating superior oil resistance property of the composites. These results confirm the possibility of ENR as a sustainable material for the production of eco-friendly composites with high oil resistance property for the footwear industry.  

scholarly journals Influence of Digestate on Physical Properties of Soil in ZD Budišov

2019 ◽  
Vol 67 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Stanislav Jaša ◽  
Barbora Badalíková ◽  
Jan Červinka
Keyword(s):  
Soil Fertility ◽  
Physical Properties ◽  
Bulk Density ◽  
Soil Structure ◽  
Physical State ◽  
Crop Yields ◽  
Crop Establishment ◽  
Air Capacity ◽  
Properties Of Soil

One of the main objectives of crop establishment is adjustment of physical properties of soil, on which indicators of soil fertility as well as economic appreciation of the resulting yield depend. During 2014–2016 yield of corn and sorghum was observed in semi‑operational experiments of ZD Budišov in relation to the quantity of the applied digestate and simultaneously, the following physical properties of soil were analysed: porosity, compaction and soil structure. After the application of digestate the porosity and minimal air capacity decreased, and reduced bulk density increased. Soil structure was affected negatively too. Overall, a trend of degradation of physical state of soil in variant with doubled dose of applied digestate was registered. Yields were always higher in variants with digestate due to a higher supply of higher amount of nutrients. Results of this observation indicate that crop yields may be higher but at the same time physical properties of soil may be impaired which may, while increasing doses of digestate, lead to irreversible degradation of soil.

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