Studies of the Vulcanization of Rubber. X. The Vulcanization of Natural Rubber with a Mixture of Sulfur Dioxide and Hydrogen Sulfide

1953 ◽  
Vol 26 (3) ◽  
pp. 559-566 ◽  
Author(s):  
B. A. Dogadkin ◽  
F. Keifetz
Keyword(s):  
Tensile Strength ◽  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Sulfur Content ◽  
Spatial Network ◽  
Smooth Curves ◽  
Multiple Cycles

Abstract 1. The dynamics of the changes of the properties of rubber during vulcanization by a mixture of sulfur dioxide and hydrogen sulfide, in distinction from conventional vulcanization by sulfur, is expressed by smooth curves. No vulcanization optimum is observed. 2. With multiple cycles of vulcanization, the increase of bound sulfur content above 3 per cent results in a decrease of tensile strength. 3. Changes of tensile strength of the vulcanizate dependent on changes of sulfur content are attributable to the influence of the density of the spatial network on the orientation processes during deformation.

Vulcanization of GR-S by the Peachey Process

1947 ◽  
Vol 20 (1) ◽  
pp. 182-183
Author(s):  
Archibald T. McPherson
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Glass Tube ◽  
The Other ◽  
Curing Process ◽  
Sulfide Sulfur ◽  
Simple Apparatus ◽  
Synthetic Rubber

Abstract It has been found possible to vulcanize GR-S synthetic rubber by subjecting it alternately to hydrogen sulfide and sulfur dioxide gases. This method for curing, known as the Peachey process, was used for natural rubber as long ago as 1921. A simple apparatus was constructed, in which strips of thinly milled rubber were placed on a screen inside a glass tube. One end of this tube was attached to valves connecting it to tanks of hydrogen sulfide, sulfur dioxide, and air, respectively. The other end of the tube led to a series of traps containing solutions which absorbed or destroyed the gases. For each test performed, natural rubber samples were placed inside the tube along with the GR-S samples for comparison. Each strip was weighed before it was inserted in the apparatus. Hydrogen sulfide was first slowly passed over the samples for a period of five minutes. Then air was blown through for a few seconds—just long enough to free the surroundings from the sulfide gas, but not long enough for the gas to be lost from solution in the rubber. Sulfur dioxide gas was next admitted and allowed to pass over the samples for five minutes. A subsequent short sweep of air through the tube completed one cycle of the curing process.

Vulcanization of Synthetic Rubbers by the Peachey Process

1948 ◽  
Vol 21 (3) ◽  
pp. 701-710
Author(s):  
Norman Bekkedahl ◽  
Fred A. Quinn ◽  
Elmer W. Zimmerman
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Styrene Copolymers

Abstract The Peachey process, which vulcanizes natural rubber by subjecting it alternately to sulfur dioxide and hydrogen sulfide gases, has been found to vulcanize the more common synthetic rubbers. The polymer studies were natural rubber, GR-S; GR-M, GR-I, GR-A, Hycar OR-15, Hycar OR-25, Hycar OS-10, Hycar OS-20, and Hycar OS-30. Good cures were obtained with all of the polymers except GR-M. None of the synthetic rubbers cured any faster than natural rubber. The nitrile and the styrene copolymers of butadiene cured at about the same rate or somewhat slower. GR-I required roughly 50 times as long as natural rubber for an equivalent cure, and GR-M required even longer.

Aids in Vulcanization of Lignin-Natural Rubber Coprecipitates. Lead, Copper, and Bismuth Oxides

1953 ◽  
Vol 26 (3) ◽  
pp. 716-730 ◽  
Author(s):  
T. R. Griffith ◽  
D. W. MacGregor
Keyword(s):  
Tensile Strength ◽  
Hydrogen Sulfide ◽  
Carbon Black ◽  
Natural Rubber ◽  
Copper Oxide ◽  
Sulfide Concentration ◽  
Bismuth Oxides ◽  
Metallic Oxides ◽  
Lead Oxides ◽  
Hydrogen Sulfide Concentration

Abstract No difficulty is experienced in the vulcanization of natural rubber containing lignin added as a dry powder, but this method of addition results in relatively low tensile strengths. When lignin solution was added to latex, however, the masterbatch obtained by coprecipitation was difficult to vulcanize. For example, if conventional acceleration was used, i.e., mercaptobenzothiazole with zinc oxide, the test slabs were soft, tacky, and logy, and could be removed from the mold only with difficulty. Although hydrogen sulfide might be a necessary intermediate in the vulcanization reaction, published experimental evidence shows that an excessive concentration of hydrogen sulfide retards vulcanization, even in the presence of powerful organic accelerators. In order to test the possibility that the retardation of cure with lignin master batches might be due to excessive hydrogen sulfide developed during vulcanization, owing to reaction of sulfur with lignin, various metallic oxides were tried which might react with hydrogen sulfide to form insoluble sulfide, and so reduce the hydrogen sulfide concentration. Lead oxides, copper oxide, and bismuth oxide were successful with lignin masterbatches, particularly when used with a dithiocarbamate accelerator. A lignin compound containing litharge, curing in 20 minutes at 282° F, had a tensile strength about 800 pounds per square inch above that obtainable with MPC carbon black. The Bashore resilience figure for the lignin compound was about double that for MPC carbon black. The aging qualities of vulcanizates containing lead oxide and lignin appear to be good, and even copper oxide, which is normally considered to be detrimental, ages satisfactorily, provided an antioxidant is included. A lignin compound containing 7 parts of copper oxide on 100 parts of rubber and 2 parts of antioxidant showed a drop of less than 20 per cent of its tensile strength after 2 days in an air oven at 90° C.

Tensile Strength of Protein-free Natural Rubber and its Vulcanizate Soaked in Water

2020 ◽  
Vol 93 (9) ◽  
pp. 293-299
Author(s):  
Luu Thanh HUYEN ◽  
Chen Ao RAN ◽  
Yoshimasa YAMAMOTO ◽  
Seiichi KAWAHARA
Keyword(s):  
Tensile Strength ◽  
Natural Rubber

Pengaruh penambahan natural rubber (NR), epoxidation natural rubber (ENR-46) dan chlorprene rubber (CR) pada sifat kompon termoplastik

2020 ◽  
Vol 26 (2) ◽  
pp. 62-69
Author(s):  
Farida Ali ◽  
Tuti I. Sari ◽  
Andi A. Siahaan ◽  
Al-Kautsar D. Arya ◽  
Tri Susanto
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Vinyl Chloride ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Nitrile Butadiene Rubber ◽  
Poly Vinyl Chloride

Penelitian ini untuk mengetahui pengaruh penambahan Natural Rubber (NR) dan Epoxidation Natural Rubber (ENR-46) dengan kompatibiliser Chlorprene Rubber (CR) pada aplikasi kompon termoplastik Poly Vinyl Chloride (PVC) dan Nitrile Butadiene Rubber (NBR), variabel penelitian meliputi ENR-46/PVC/NBR/CR, NR/PVC/NBR/CR dan CR-NR/PVC/NBR, CR-ENR-46/PVC/NBR. Parameter pengujian sifat fisik-mekanik : Hardness (Shore A), Tensile Strength (Mpa), Elongation at Break (%) dan ketahanan terhadap pelarut minyak (n-Pentane, Toluene, Hexane dan Pertalite). Hasil penelitian didapatkan untuk sifat fisik-mekanik, semakin banyak penambahan NR Kekerasan kompon termoplastik akan menurun, Tensile Strength dan Elongation at Break kompon akan meningkat begitu juga dengan CR-NR. Tetapi berbanding terbalik hasilnya untuk ENR-46 dan CR-ENR-46. Pengujian Ketahanan terhadap pelarut minyak semakin banyak penambahan ENR-46 Ketahanan kompon termoplastik terhadap pelarut akan meningkat, hasil yang sama juga pada CR-ENR-46. Tetapi berbanding terbalik hasilnya dengan penambahan NR dan CR-NR pada kompon termoplastik.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

scholarly journals Composites from Thermoplastic Natural Rubber Reinforced Rubberwood Sawdust: Effects of Sawdust Size and Content on Thermal, Physical, and Mechanical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
High Density Polyethylene ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Shore Hardness ◽  
Thermoplastic Natural Rubber ◽  
Plastic Content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.

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