Processing and characterization of natural rubber/stearic acid-tetra-needle-like zinc oxide whiskers medical antibacterial composites

ABSTRACTPlasma polymerized acetylene films contained mono- and di-substituted acetylene groups, aromatic groups, and carbonyl groups which resulted from reaction of residual free radicals with oxygen when the films were exposed to the atmosphere. There was some evidence for formation of acetylides in the interphase between the films and the substrates. Reactions occurring in the interphase between the plasma polymerized films and natural rubber were simulated using a model rubber compound consisting of a mixture of squalene, zinc oxide, carbon black, sulfur, stearic acid, diaryl-p-diphenyleneamine, and N,N-dicyclohexylbenzothiazole sulfenamide (DCBS). Zinc oxide and cobalt naphthenate reacted with stearic acid to form zinc and cobalt stearates. The stearates reacted with the benzothiazole sulfonamide moiety of DCBS and with sulfur to form zinc and cobalt accelerator complexes and perthiomercaptides. The complexes and perthiomercaptides reacted with squalene and the plasma polymer to form pendant groups which eventually disproportionated to form crosslinks between squalene and the primer. Migration of double bonds during reaction of the model rubber compound with the films resulted in formation of conjugated double bonds in squalene.

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Effect of Sulfur and Dicumyl Peroxide on Vulcanization of Natural Rubber with Tetramethylthiuram Disulfide and Zinc Oxide

Rubber Chemistry and Technology ◽

10.5254/1.3547330 ◽

1970 ◽

Vol 43 (6) ◽

pp. 1294-1310 ◽

Cited By ~ 9

Author(s):

S. P. Manik ◽

S. Banerjee

Keyword(s):

Zinc Oxide ◽

Stearic Acid ◽

Natural Rubber ◽

Reaction Mechanisms ◽

Elemental Sulfur ◽

Initial Rate ◽

Dicumyl Peroxide ◽

Tetramethylthiuram Disulfide ◽

Sulfur Vulcanization ◽

Salient Features

Abstract The salient features of both non-elemental sulfur vulcanization by TMTD and elemental sulfur vulcanization promoted by TMTD both in presence and absence of ZnO and stearic acid have been studied. TMTD increases the rate of DCP decomposition and lowers the crosslinking maxima due to DCP depending on its concentration. However, with higher amounts of TMTD the initial rate of crosslinking is increased with the increased amount of TMTD, while crosslinking maxima are still lowered due to reversion. ZnO or ZnO-stearic acid, however, seems to alter the entire course of the reaction. Both the crosslink formation and TMTD decomposition are much higher in presence of ZnO or ZnO-stearic acid, but stearic acid seems to have no effect. The reaction mechanisms for TMTD accelerated sulfuration in absence and presence of ZnO have also been studied.

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Preparation and Characterization of Radiopaque Natural Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3547971 ◽

2006 ◽

Vol 79 (5) ◽

pp. 870-880 ◽

Cited By ~ 1

Author(s):

V. S. Nisha ◽

Rani Joseph

Keyword(s):

Zinc Oxide ◽

Natural Rubber ◽

Physical Properties ◽

Thermo Gravimetric Analysis ◽

Barium Sulphate ◽

Gravimetric Analysis ◽

X Ray ◽

Vis Spectroscopy ◽

Shielding Material

Abstract Currently radiopaque polymers are of great interest to medicine and dentistry because of their wide area of applications such as catheters, surgical tools, dental products, radiation shielders etc. Lead has historically been used as the shielding material, but not without health and environmental concerns. In this work, we have prepared radiopaque materials from natural rubber (NR) through different routes. Natural rubber was iodinated and characterized using UV-VIS spectroscopy, thermo gravimetric analysis and clinical X-ray techniques. The physical properties of Iodinated NR compounds prepared at ambient and high temperatures were studied. The low temperature cured samples showed better radiopacity and conductivity than high temperature cured samples. Radiopaque NR was prepared using radiopacifiers like barytes, barium sulphate, zinc oxide and active zinc oxide. The physical properties of the NR vulcanizates with different radiopacifiers were studied. Clinical X-ray techniques have been used to confirm the radiopacity. The optical density of the samples were measured and compared with that of conventionally used lead shield.

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Some Aspects on the Crosslink Reaction of Natural Rubber with Dipentamethylene Thiuram Tetrasulfide

Rubber Chemistry and Technology ◽

10.5254/1.3547583 ◽

2000 ◽

Vol 73 (1) ◽

pp. 89-100 ◽

Cited By ~ 6

Author(s):

L. González ◽

A. Rodríguez ◽

A. del Campo ◽

A. Marcos-Fernández

Keyword(s):

Zinc Oxide ◽

Stearic Acid ◽

Natural Rubber ◽

Induction Times

Abstract The mechanism of vulcanization of natural rubber with the sulfurating agent dipentamethylene thiuram was studied. On the transformation from crosslink precursor to crosslink, the route via disproportionation is preferred. In the presence or absence of zinc oxide and stearic acid as activators, the formation of the crosslink precursor follows similar processes, while the main difference is in the reaction induction times. In addition, the desulfuration reaction was favored by the presence of zinc oxide.

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Investigation on the Influence of Various Kinds of Soaps on the Mechanical Properties of Silica Filled Composites Based on Natural Rubber

Polymers and Polymer Composites ◽

10.1177/096739111802600407 ◽

2018 ◽

Vol 26 (4) ◽

pp. 325-334

Author(s):

Omar A. Al-Hartomy ◽

Ahmed A. Al-Ghamdi ◽

Said A. Fahra Al-Said ◽

Nikolay Dishovsky ◽

Mihail Mihaylov ◽

...

Keyword(s):

Mechanical Properties ◽

Zinc Oxide ◽

Fatty Acid ◽

Stearic Acid ◽

Natural Rubber ◽

Rubber Compounds ◽

Zinc Salts

The aim of this study was to investigate the influence that different fatty acid zinc salts had on the rheological, curing and mechanical properties of natural rubber based composites filled with silica and containing bi-functional organosilanes in the presence or absence of zinc oxide. The results demonstrated that the combination of zinc oxide and zinc soaps had a strongly pronounced anti-reversion effect. The absence of reversion in the cure curves of the rubber compounds comprising a combination of zinc oxide, stearic acid and zinc soaps, results in retention of their mechanical properties, even after overcure.

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Studies on Dicumylperoxide Vulcanization of Natural Rubber in Presence of Sulfur and Accelerators

Rubber Chemistry and Technology ◽

10.5254/1.3539254 ◽

1969 ◽

Vol 42 (3) ◽

pp. 744-758 ◽

Cited By ~ 9

Author(s):

S. P. Manik ◽

S. Banerjee

Keyword(s):

Mechanical Properties ◽

Zinc Oxide ◽

Stearic Acid ◽

Natural Rubber ◽

Rate Constant ◽

Crosslink Density ◽

First Order

Abstract The effect of sulfur, MBT, zinc oxide and stearic acid, either singly or in mixtures, on the DCP vulcanization of NR has been studied. In all cases DCP decomposes by a first order law, but the rate constant is higher in presence of MBT. Sulfur and MBT, separately or together reduce the crosslink density, each mole of Sx or MBT destroying one mole of DCP. In mixes containing DCP together with sulfur, MBT, zinc oxide and stearic acid the crosslink density is initially additive. The mechanical properties and the aging characteristics of the vulcanizates have also been reported.

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Extraction and identification of fillers and pigments from pyrolyzed rubber and tire samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163332 ◽

1996 ◽

Vol 54 ◽

pp. 174-175

Author(s):

P. Sadhukhan ◽

J. B. Zimmerman

Keyword(s):

Zinc Oxide ◽

Electron Microscope ◽

Carbon Black ◽

Natural Rubber ◽

Transmission Electron Microscope ◽

Rolling Resistance ◽

Synthetic Polymers ◽

Nitrogen Atmosphere ◽

Transmission Electron ◽

Curing Agents

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.

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