Studies of Hard Rubber Reactions. III. Changes in Acetone-Extractable Substances during Vulcanization

1937 ◽  
Vol 10 (4) ◽  
pp. 787-791
Author(s):  
Seiiti Numajiri
Keyword(s):  
Tensile Strength ◽  
Turning Point ◽  
Acetone Extract ◽  
Acetone Extraction ◽  
Maximum Value ◽  
Rubber Compounds ◽  
Preceding Communication ◽  
Definite Period ◽  
Consequent Increase

Abstract 1. To explain chemically the fundamental hard rubber reactions which take place during the vulcanization, changes in the acetone-extractable substances, as well as in tensile strength, elongation, and hardness, during vulcanization were studied. 2. Preliminary experiments on acetone extraction with the author's apparatus indicated that a 20-hour extraction was ideal for the purposes of the investigation, and extractions extending to extremely long periods were unsuitable in the present experiments. 3. The corrected acetone extract or organic acetone-soluble substances do not either increase or diminish steadily throughout vulcanization, but show a maximum value at a definite period of vulcanization. The appearance of this maximum value, which also corresponds to characteristic changes in tensile strength, elongation, and hardness (cf. the preceding Communication) is a turning point where the hard rubber reaction diminishes rapidly. 4. To explain chemically the appearance of a maximum value and consequent increase and decrease in the percentage of acetone-soluble substances (corrected) it may be considered that the rubber or rubber compounds with different degrees of vulcanization are polymerized at a certain period of vulcanization, depending on the action of heat, accelerators and agencies, and that the amount of acetone-soluble substances is governed by these factors.

Effect of Brown Vulcanized Vegetable Oil on Ozone Resistance, Aging, and Flow Properties of Rubber Compounds

1987 ◽  
Vol 60 (1) ◽  
pp. 159-175 ◽  
Author(s):  
Samir H. Botros ◽  
Fawzia Fabd El-Mohsen ◽  
Eberhard A. Meinecke
Keyword(s):  
Tensile Strength ◽  
Soybean Oil ◽  
Linseed Oil ◽  
Acetone Extract ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
High Concentrations ◽  
Ozone Resistance ◽  
Free Sulfur

Abstract The addition of accelerator to vegetable oils during the preparation of brown V.V.O. results in a decrease of the free sulfur and the acetone extract values of the obtained V.V.O. In addition, the reaction time necessary to achieve the gel state is reduced. NR vulcanizates containing brown V.V.O. based on soybean oil are superior in retention of their tensile strength and 100% modulus after aging to those containing V.V.O. based on boiled linseed oil and dehydrated castor oil. The heat resistance of NR vulcanizates which contain brown V.V.O. increases as the amounts of the free sulfur and the acetone extract in the V.V.O. decrease. Addition of small amounts of brown V.V.O. to NR and SBR compounds helps to maintain the tensile strength after aging. However, the addition of high concentrations of the V.V.O. reduces the aging properties. The addition of brown V.V.O. based on soybean oil and TMTD to NR compounds used for the manufacture of printer rolls and rubber hoses enhances the ozone resistance of the rubber vulcanizates. Furthermore, the addition of this type of V.V.O. to NR and SBR compounds is advantageous because of: (1) delay of the onset of melt fracture, (2) reduction of extrudate swell, (3) smoother extrudate surfaces, (4) dimensional stability of NR and SBR extrudates.

Effect of Diameter and Surface Area of Carbon Black Particles on Certain Properties of Rubber Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Particle Diameter ◽  
Stiffness Modulus ◽  
Carbon Structures ◽  
Rubber Compounds ◽  
Regular Manner ◽  
Tear Resistance

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.

Effect of Various Types of Carbon Black on Certain Physical Properties of Rubber Compounds

1928 ◽  
Vol 1 (3) ◽  
pp. 458-464
Author(s):  
D. J. Beaver ◽  
T. P. Keller
Keyword(s):  
Carbon Black ◽  
Physical Properties ◽  
Acetone Extract ◽  
Acetylene Black ◽  
Direct Proportion ◽  
Rubber Compounds ◽  
Oil Adsorption ◽  
Iodine Adsorption ◽  
Standard Channel

Abstract The data presented herein show that in general the presence of oxygen on carbon black retards the rate of vulcanization in direct proportion to the amount of oxygen present and also decreases the maximum physical properties obtainable with a given amount of accelerator. The aging data show that the presence of this oxygen on the black increases the rate of aging as the amount of oxygen increases, but not in direct proportion to the per cent of this oxygen present. It can be concluded, therefore, that compounds which contain a small amount of oxygen, such as thermatomic, G black, or acetylene black, will give better aging stocks than compounds containing higher amounts of oxygen such as lampblack and standard channel blacks. No correlation could be found between the acetone extract, iodine adsorption, or oil adsorption, and the effect of these blacks on the rate of cure or aging.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

Studies on the Acetone Extraction of Raw Rubber

1935 ◽  
Vol 8 (4) ◽  
pp. 604-612
Author(s):  
Hidemaro Endô
Keyword(s):  
Acid Value ◽  
Acetone Extract ◽  
Water Bath ◽  
Acetone Extraction ◽  
Saponification Value ◽  
Alcoholic Potash ◽  
Saponifiable Matter ◽  
Acetone Extracts ◽  
Hcl Solution

Abstract (1) For the determination of the saponification value of the acetone extract, 20 cc. 0.2 N alcoholic potash is added to the extract and the flask is heated on a water bath for 60 minutes. It is then titrated with 0.1 N HCl solution, using phenolphthalein as indicator. (2) When the saponification values of the acetone extracts of 8, 16, and 24 hours are compared, the saponification value of the 8 hour extract is seen to be high, while those of 16 and 24 hour extracts are low. This indicates (a) that the 8 hour extract contains a higher percentage of saponifiable matter than the 16 and 24 hour extracts; (b) the quantity of rubber hydrocarbon which is dissolved in the acetone extract increases with increasing time of extraction, and (c) the acid value of the acetone extract decreases during the period of extraction from 16 to 24 hours. (3) Regarding the saponification values (R) of the acetone extracts of 8, 16, and 24 hours, similar remarks may be made as in (2) above.

scholarly journals The Effect of Injection Molding on Physical Properties of EPDM Rubber

2018 ◽  
Vol 210 ◽  
pp. 02039
Author(s):  
Adam Skrobak ◽  
Vojtech Senkerik ◽  
Vaclav Janostik
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Physical Properties ◽  
Standard Method ◽  
Epdm Rubber ◽  
Tear Strength ◽  
Injection Method ◽  
Rubber Compounds ◽  
Cutting Out ◽  
Injection Molded

The paper a part of research aimed at the alternative of preparing test samples by injection molding. Such an alternative could bring more objective results in the field of testing samples produced in the same technology. The research is aimed at changing the preparation of rubber testing samples - replacing the standard method according to ISO 23529 by the injection method, especially with the use of rubber compounds for injection molding. This article compares and evaluates the selected physical properties (tensile strength and tear strength) of EPDM rubber injection molded samples with samples prepared by the standard method - cutting out of a compression molded plate. The results have shown that using the injection molded samples we will achieve more objective results mainly to determine the tear strength. In the case of tensile strength, the differences are not so significant.

The Effect of Second Filler on Cure Characteristic and Mechanical Properties of Si-69 Treated Precipitate Silica/NR Composite

2009 ◽  
Vol 79-82 ◽  
pp. 2183-2186 ◽  
Author(s):  
Chanchai Thongpin ◽  
C. Sripetdee ◽  
N. Papaka ◽  
N. Pongsathornviwa ◽  
Narongrit Sombatsompop
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Rubber Compound ◽  
Maximum Torque ◽  
Elongation At Break ◽  
Rubber Vulcanizate ◽  
Rubber Compounds ◽  
Cure Time ◽  
Cure Characteristic

Silica has been widely used as non-black reinforcing filler, however, the filler-filler interaction has been an important issue. Cure characteristic and mechanical properties of the rubber compound and rubber vulcanizate were affected both by filler-rubber interaction and filler-filler interaction. There have been, presently, a number of natural fillers which are also used as fillers for the rubber, i.e. fly ash, sawdust and zeolite. This work therefore will study the effect of second filler added into the 13% Si-69 treated precipitate silica (PSi) filled natural rubber compounds. It was revealed that the scorch and cure time of the rubber compound increased with the content of treated PSi. This was the effect of excess of the silane treated onto PSi which would agglomerate and form the cluster of polysiloxane and would then be able to absorb vulcanizing accelerator resulting in extending the scorch and cure time of the rubber compounds. However, this effect was over ruled with the reinforcing effect as could be seen by the increasing, with the contents of PSi, of maximum torque and mechanical properties of the vulcanizates. The NR compounded with treated PSi content of 20 phr selected to study the effect of excess silane on the cure characteristic of hybrid fillers NR composite. The addition of sawdust led to longer scorch time and cure time but not much change of the maximum torque. As expected, the modulus of the rubber vulcanizate increased with the sawdust content whereas the tensile strength and elongation at break decreased with the sawdust content. The incorporation of zeolite could accelerate the cure reaction therefore both scorch time and cure time decreased. The maximum torque also increased with the content of zeolite. Both modulus and tensile strength increased with the content of the zeolite whereas elongation at break tended to be unchanged. In the case of using fly ash as the second filler, the cure time tended to be unchanged. However, the maximum torque tended to be increased with the content of fly ash. It was found that the modulus, tensile strength increased but elongation at break decreased. Interestingly, the excess of Si-69 used effect pronouncedly for the addition of zeolite and fly ash cases as the excess silane could promote the interaction between fillers surface and rubber molecule accept for sawdust

Alternating Behavior of Fatty Acids in Rubber Compounds

1930 ◽  
Vol 3 (4) ◽  
pp. 612-614
Author(s):  
T. L. Garner
Keyword(s):  
Fatty Acids ◽  
Tensile Strength ◽  
Crystalline Structure ◽  
Melting Points ◽  
Gradual Reduction ◽  
Rubber Compounds ◽  
The Difference

Abstract It has been shown (Bayer, Ber., 10, 1286 (1877); Garner and Randall, J. Chem. Soc., 125, 881 (1924)) that the alternations in the melting points and heats of crystallization of normal fatty acids were due to differences in the crystalline structure. Two distinct curves of behavior corresponding to the acids with odd and even numbers of carbon atoms have been shown for the heats of crystallization. McKee (Naturwissenschaften, 11, 938 (1923)) discussing the fats used in the diet of diabetics, states that in the case of glycerides of acids with an uneven number of carbon atoms these are tolerated and their use leads to gradual reduction in acidosis. Glycerides having an even number of carbon atoms break down during metabolism to form butyric, oxybutyric, and acetoacetic acids. Smith and Boone (Ind. Eng. Chem., 19, 398 (1927)) have experimented with the addition of purified fatty acids to standard mixings of different kinds of raw rubber. They employed molar proportions of the acid to conform with the recommendations of Kratz, Flower, and Coolidge (Ind. Eng. Chem., 12, 317 (1920)) that comparisons of organic accelerators should be made with molecularly equivalent amounts of the substances in question. They determined the tensile strength and elongation of the vulcanized products and found no relations between the elongation and the number of carbon atoms present in the acids, but in the case of the tensile strength an alternating effect was evident, the extent of the differences being affected by cure. The tests were carried out on two kinds of rubber, namely, blanket crepe and pale crepe, and the alternating effect of the acids on the tensile strength was more marked in the former case. As pointed out in the paper, the difference in behavior of the two kinds of rubber when treated with fatty acids was presumably due to the difference in the kind and proportions of acids which they originally contained. In fact, in the case of pale crepe the fatty acids already present in the raw rubber masked the alternating behavior to a marked extent, and the curve obtained was in most respects quite different from that obtained with blanket crepe.

Reinforcement of Polypropylene Using Micro-Fillers

2013 ◽  
Vol 300-301 ◽  
pp. 1321-1324
Author(s):  
Hieu Giang Le ◽  
Shyh Chour Huang ◽  
Van Son Nguyen ◽  
Thanh Phong Dao
Keyword(s):  
Tensile Strength ◽  
Maximum Value ◽  
Micro Fillers

This paper focuses on the effect the ratio of filler (Na10MB3A) on the tensile strength of polypropylene (PP). This filler has been added to PP in various ratios and mixed evenly before injecting. The tensile strength of PP increases gradually when the ratio of filler increases. Tensile strength reaches its maximum value with a certain ratio of filler, and thereafter the strength decreases as the ratio of fillers is increased. This research revealed that the tensile strength of PP can rise by approximately 13.5% with the addition of Na10MB3A at a ratio of 3%.

Preliminary Study on Curing of Thick Rubber Article

2015 ◽  
Vol 1134 ◽  
pp. 23-27
Author(s):  
Siti Zulaikha Ibrahim ◽  
Che Mohd Som Said ◽  
Mohamad Asri Ahmad ◽  
Azemi Samsuri
Keyword(s):  
Tensile Strength ◽  
Temperature Region ◽  
The State ◽  
Curing Temperature ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cure Time ◽  
Zinc Diethyldithiocarbamate ◽  
Preliminary Study ◽  
Rubber Article

In this study, several batches of natural rubber (SMR L) were compounded with three different types of accelerators, which were N-cyclohexylbenzothiazole-2-sulphenamide (CBS), diphenylguanidine (DPG) and zinc diethyldithiocarbamate (ZDEC). ZDEC is known as an ultrafast accelerator. The rubber compounds were cured at 140°C, 130°C, 120°C, 110°C and 100°C in accordance with the temperature gradients observed within the thick rubber block. The main aim of this study is to cure the rubber at each temperature region to the same cure time as that of the outermost region (20 minutes at 140°C). The amount of sulfur and accelerator were adjusted accordingly at each curing temperature to match the state of cure at 140°C. The state of cure of of the vulcanized rubbers were measured using hardness and tensile strength. The same state of cure is achieved if the hardness and tensile strength value are within ±2 IRHD and ±3 MPa, respectively with that of the control vulcanized rubber (hardness and tensile strength cured at 140°C). The results shows that the hardness and tensile strength of the vulcanized rubber at each temperature region are within the expected margins. The results clearly indicated that the type and amount of accelerators, and the amount of sulfur were correctly chosen at each temperature.

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