Scanning electron microscopy studies on nitric acid corrosion of natural rubber vulcanizates

1985 ◽  
Vol 10 (4) ◽  
pp. 299-317 ◽  
Author(s):  
Sania Akhtar ◽  
Dipak K. Setua ◽  
Prajna P. De ◽  
Sadhan K. De
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nitric Acid ◽  
Natural Rubber ◽  
Acid Corrosion ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron

Ridge Formation during the Abrasion of Elastomers

1982 ◽  
Vol 55 (4) ◽  
pp. 1055-1062 ◽  
Author(s):  
A. K. Bhowmick
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Rubber ◽  
Crack Growth ◽  
Unit Length ◽  
Crack Growth Resistance ◽  
Small Particles ◽  
The Matrix ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron

Abstract Scanning electron microscopy studies have been carried out on gum and filled natural rubber vulcanizates to investigate the ridge formation in the abrasion of elastomers. The first step of the ridge formation is the occurrence of small particles on the smooth abrading surface by a process of microtearing. Their size and shape depend upon the frictional force per unit length of the abrader in contact with the rubber and the nature of the rubber and the abrasive. These particles are not loose, and, hence, are not removed easily if the strength of the matrix is high. Further particles appear on the surface with continued abrasion. These particles coalesce to form fine ridges on the surface which become progressively thicker. Removal of these ridges depends upon the crack growth resistance and strength of the vulcanizate as well as on the dissipation of sliding energy in the matrix. Gum and filled natural rubber vulcanizates follow similar mechanisms of ridge formation. Due to low strength and crack growth resistance of the gum natural rubber, the abrasion resistance is poor compared to the filled ones.

Influence of the Treatment with Sulfuric Acid on Adhesion of Natural Rubber and Cast Polyurethane Elastomers

2012 ◽  
Vol 452-453 ◽  
pp. 86-90 ◽  
Author(s):  
Zhi Yi Zhang ◽  
Hui Jun Niu ◽  
Jia Jia Zhang ◽  
Yan Yun Cui
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Sulfuric Acid ◽  
Natural Rubber ◽  
Angle Measurement ◽  
Polyurethane Elastomers ◽  
Adhesion Properties ◽  
Rubber Surface ◽  
Scanning Electron

In this study, natural rubber (NR) was treated with sulfuric acid to improve its adhesion properties to polar polymer. T-peel strength tests, scanning electron microscopy, contact-angle measurement (water), Energy Dispersive X-ray Detector were used to analyze the nature of the NR surface modifications which were carried out with sulfuric acid. A noticeable decrease in contact angle was observed on the rubber surface by contact-angle measurements which can be ascribed to the increase of oxidized moieties on the rubber surface. EDX revealed that oxidized moieties were created through treatment with sulfuric acid. The surface modification and mode of bond failure were studied by scanning electron microscopy (SEM). Immersion in sulfuric acid for 15min produced the maximum adhesion strength (10kN/m) and produced a mixed failure mode (interface & rubber failure in the rubber). Treatment with sulfuric acid produced improved wettability as well as chemical (surface oxidation) and morphological modifications (roughness) of the rubber surface.

scholarly journals Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: Influence of GTR source and irradiation time

2018 ◽  
Vol 52 (22) ◽  
pp. 3099-3108 ◽  
Author(s):  
Xavier Colom ◽  
Marc Marín-Genescà ◽  
Ramon Mujal ◽  
Krzysztof Formela ◽  
Javier Cañavate
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Natural Rubber ◽  
Irradiation Time ◽  
Rubber Composites ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Scanning Electron

Ground tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160℃. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical behaviour, thermal properties and morphology of natural rubber/ground tire rubber composites was studied. The interfacial interactions between ground tire rubber and natural rubber as function of ground tire rubber source and irradiation time were evaluated by Fourier transform infrared spectroscopy, thermogravimetric analysis, tensile tests, swelling measurements and scanning electron microscopy. The results showed that irradiation of ground tire rubber slightly enhanced tensile properties and cross-link density of natural rubber/ground tire rubber composites. This effect was more evident in the case of ground tire rubbertruck because of its higher content of natural rubber and was reflected in changes in the interfacial adhesion, which were confirmed by the results of Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy analysis.

scholarly journals Properties of Natural Rubber-Based Composites Containing Fullerene

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Omar A. Al-Hartomy ◽  
Ahmed A. Al-Ghamdi ◽  
Falleh Al-Salamy ◽  
Nikolay Dishovsky ◽  
Desislava Slavcheva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dielectric Properties ◽  
Natural Rubber ◽  
Elastomeric Matrix ◽  
Transmission Electron ◽  
Aging Resistance ◽  
Filler Dispersion ◽  
Scanning Electron

In this study the influence of fullerenes in concentrations from 0.5 to 1.5 phr on both the vulcanization characteristics of the compounds and physicomechanical, dynamic, and dielectric properties and thermal aging resistance of nanocomposites on the basis of natural rubber has been investigated. The effect of the filler dispersion in the elastomeric matrix has been also investigated. Neat fullerene and the composites comprising it have been studied and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

EFFECT OF CURE EFFICIENCY ON PROPERTIES OF GUM AND BLACK FILLED NATURAL RUBBER VULCANIZATES

2011 ◽  
Vol 84 (2) ◽  
pp. 229-242 ◽  
Author(s):  
Gary R. Hamed ◽  
Kanoktip Boonkerd
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Cure Time ◽  
Cracking Pattern ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron ◽  
Fracture Specimens ◽  
Strength Effect

Abstract Effects of the sulfur cure efficiency on the reversion behavior and the normal and edge-cut tensile strength of gum and black filled natural rubber (NR) vulcanizates were studied. N, N-dicyclohexyl-2-benzothiazole sulfenamide (DCBS) was used as an accelerator. A series of five vulcanizates with high to low cure efficiencies was prepared by increasing the sulfur (S) to DCBS ratios within the range of 0.26–6.66. All vulcanizates were formulated to have the same crosslink density. The degree of reversion (%) calculated from cure curves of gum and black filled NR at 20 min above the cure time (tc100) passed through maximum with decreasing cure efficiencies. For both gum and black filled NR, the highest degree of reversion (%) was observed at the S/DCBS ratio of 1.17. The normal tensile strengths of gum and black filled NR were directly proportional to the cure efficiency. For gum NR vulcanizates, the edge-cut tensile strength was markedly influenced by cure efficiency. Similar to the normal tensile strength, the gum NR vulcanizates cured with the lowest cure efficiency showed the lowest edge-cut tensile strength. Effect of the cure efficiency on the edge-cut tensile strength was less in the case of black filled NR vulcanizates. However, the black filled NR vulcanizates cured with the lowest cure efficiency also showed the lowest edge-cut tensile strength. The cut tip characteristics of the fracture specimens were investigated using scanning electron microscopy. The gum specimens showed only the simple lateral cracking pattern, while all black filled specimens showed the longitudinal cracking pattern. Four different cracking patterns of the black filled specimens were identified. The distribution of cracking patterns depended strongly on the size of precut and the cure efficiency.

scholarly journals Structure and microstructure of coronary dentin in non-erupted human deciduous incisor teeth

2002 ◽  
Vol 13 (3) ◽  
pp. 170-174 ◽  
Author(s):  
Luciane R.R S. Costa ◽  
Ii-Sei Watanabe ◽  
Márcia C. Kronka ◽  
Marcelo C.P. Silva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nitric Acid ◽  
Light Microscopy ◽  
Three Dimensional ◽  
Dentinal Tubules ◽  
Sem Study ◽  
Structure And Microstructure ◽  
Hematoxylin Eosin ◽  
Scanning Electron

The dentin structure of non-erupted human deciduous mandibular and maxillary central and lateral incisor teeth was studied employing light and scanning electron microscopy. For light microscopy, nitric-acid-demineralized and ground sections were used. The sections were stained by hematoxylin-eosin, picrosirius and azo-carmim methods, and ground specimens were prepared using a carborundum disk mounted in a handpiece. For SEM study, teeth were frozen in liquid nitrogen and fractured at longitudinal and transversal directions. Structurally, demineralization and ground methods revealed tubules with primary and secondary curvatures, canaliculi, giant tubules, interglobular dentin, predentin, and intertubular dentin. Scanning electron microscopy showed three-dimensional aspects of dentinal tubules, canaliculi, peritubular dentin, intertubular dentin, and predentin. This study contributes to knowledge about dentin morphology showing characteristics of teeth not yet submitted to mastication stress.

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