Ozone and Sunlight Effect on Aging of Carbon Black Vulcanizates

1953 ◽  
Vol 26 (1) ◽  
pp. 127-135
Author(s):  
George E. Popp ◽  
Lynn Harbison

Abstract Carbon black, regardless of type, particle size, structure, and physical properties imparted, does not affect the rate or degree of checking or cracking in natural-rubber or low-temperature polymer compounds when subjected to weather or ozone exposure. Natural rubber will withstand much longer periods of exposure than the synthetic polymer studied. A pronounced degree of ozone and weather cracking and checking will result if no antioxidant is compounded into the synthetic polymer. An MAF black-synthetic polymer compound may be substantially improved in its resistance to ozone and weather resistance by selection and application of the proper antichecking ingredients.

1970 ◽  
Vol 43 (2) ◽  
pp. 222-228 ◽  
Author(s):  
A. G. Thomas ◽  
J. M. Whittle

Abstract The dependence of tensile strength of a number of vulcanizates on temperature has heen studied. A critical temperature θc is found for natural rubber at which an abrupt change in strength occurs. This temperature depends on degree of crosslinking and also on the nature of the vulcanizing system. The presence of carbon black filler increases the strength above θc but has little influence on the value of θc or the strength at temperatures below it. The behavior can be explained qualitatively in terms of a change in mechanism of rupture from essentially a tear process above θc to a crack growth process below it. The influence of vulcanizing system is mainly due to changes in the nature of the crosslink rather than changes in regularity of the main chain as shown by the rate of low temperature crystallization.


1989 ◽  
Vol 62 (2) ◽  
pp. 179-194 ◽  
Author(s):  
Y. Udagawa ◽  
M. Ito

Abstract The low-temperature x-ray method can detect the orientation of NR molecules in both vulcanizate samples and nonvulcanizate samples of NR compounds. The presence of carbon black is important for causing the orientation. NR molecules orient in the direction of stretch-relaxation in the case of uniaxially fatigued vulcanizates or in the direction of shear in the case of nonvulcanizates prepared by various processing methods. The orientation of NR molecules in nonvulcanizates usually disappears when vulcanized, but a fairly large extent of molecular orientation remains, even after vulcanization, if there exist crosslinks in the oriented nonvulcanizate and the sample is prevented from shrinkage.


1953 ◽  
Vol 26 (4) ◽  
pp. 862-868
Author(s):  
G. J. van Amerongen

Abstract In this investigation an attempt was made to determine to what extent the solubility of oxygen in natural rubber and the aging resistance are influenced by the incorporation of carbon blacks of various particle sizes in the rubber. The influence of the particle size of carbon black on the oxidizability of GR-S loaded with carbon black had already been proved by Winn, Shelton, and Turnbull. In their explanation of this effect, carbon black was considered to be a catalyst for the oxidation reaction of rubber, although nothing was known about the nature of this catalytic action. Moreover, measurements with natural rubber were lacking.


1982 ◽  
Vol 55 (1) ◽  
pp. 103-115 ◽  
Author(s):  
C. H. Chen ◽  
J. L. Koenig ◽  
J. R. Shelton ◽  
E. A. Collins

Abstract The effect of carbon black upon the reversion process in the sulfur-accelerated vulcanization of natural rubber has been studied. It is found that black-filled cure systems have a faster rate of vulcanization and better reversion resistance. The net decrease of trans-methine content, which is equivalent to the improvement of reversion resistance, is found to be at most 15%, with the initial 10 pphr loading yielding the greatest effect. However, those decreases of trans-methine content are small when compared with the substantial effects of these fillers on the physical-mechanical properties of the vulcanizate, which is a linear function of black loading. In general, the smaller the black particle size, the greater the improvement of the reversion resistance, but particle size alone is not the only factor affecting reversion. A universal curve is obtained for correlating the amount of reversion and trans-methine content, which is independent of any natural rubber-based curing system, operating conditions and type of fillers.


2014 ◽  
Vol 11 (6) ◽  
pp. 565-574
Author(s):  
J. Nwabanne ◽  
P. Igbokwe ◽  
E. Ezeonyebuchi

The effect of partial replacement of carbon black by Palmyra palm fiber on the cure characteristics, physico-mechanical and swelling properties of natural rubber vulcanizates was studied. The Palmyra palm fibers were extracted, treated and characterized so as to determine pH, moisture content, and ash content, loss on ignition, conductivity, cellulose, lignin, Hemicellulose, cellulose/lignin ratio and Acid soluble lignin. The functional groups in the Palmyra palm fiber was also determined using FTIR. The Palmyra palm powder with an average particle size of 75 μm was used in this study. The natural rubber/carbon black/Palmyra palm fiber (NR/CB/PPF) composites having eight different loadings, 0/70, 10/60, 20/50, 30/40, 40/30, 50/20, 60/10, 70/0, were prepared using a laboratory size two roll mill. The maximum Torque of NR/CB/PPF composites increased with increasing commercial filler loading ratio. The scorch time and cure time of NR/CB/PPF composites decreased as the ratio of CB loading increased. The tensile strength, modulus of elongation, tear strength and abrasion resistance of all the composites increased as the commercial filler loading ratio increased. This is due to the presence of the commercial filler which gave a better filler interaction. Also this behavior can be attributed to the particle size and surface area of the fillers used as the fillers with small particle size usually have a larger surface area which supports better filler-rubber interaction. The hardness increased as the palmyra palm fiber loading increased. The elongation at break decreases as carbon black filler loading increases except for the composite with CB/PPF ratio of 10/60. The effect of filler loading on the swelling behavior of NR/CB/PPF composites was also investigated in aromatic and aliphatic compounds. Result showed that the composites with more carbon black has less absorption than those with more palmyra palm fiber showing that the compounds with more carbon black has better interaction than those with palmyra palm fiber.


2016 ◽  
Vol 705 ◽  
pp. 24-29
Author(s):  
Karl C. Ondoy ◽  
Bryan B. Pajarito

This study reports the results of investigation on the main and interaction effects of grit type, aging temperature, and aging time on particle size of ground natural rubber/zeolite (GNR/Z) composite powder using general factorial design of experiment. GNR/Z composite powder produced by mechanical grinding is porous, like an aggregated chain structure. These aggregates exist in clusters of irregular shape. Analysis of variance (ANOVA) shows that the effects of aging temperature and aging time depend on the particle size range. GNR/Z composite powder with large particle size is produced when aging is done at low temperature and short time due to high resistance of rubber to oxidation. On the other hand, GNR/Z composite powder with small particle size is produced when aging is done at low or high temperature and longer aging time. Low temperature condition offers high O2 concentration available to oxidize rubber while high temperature condition leads to more chain scissions due to higher oxidation rate.


2012 ◽  
Vol 626 ◽  
pp. 114-120 ◽  
Author(s):  
Mahendra Anggaravidya ◽  
Sudirman Sudirman ◽  
Bambang Soegijono ◽  
Emil Budianto ◽  
Martin Djamin

The mechanical properties of natural rubber can be enhanced by the addition of carbon black. The mechanical properties change is highly affected by particle size and carbon black structure used. A modification of N660 carbon black was conducted in the research by sonoficating the carbon black for 3 and 5 hours (N600-M3; M5). The results of adding modified carbon black were characterised by Particle Size Analysis (PSA), Scanning Electron Microscopes - Energy Dispersive Spectrometry (SEM-EDS) and Thermogravimetric Analysis (TGA). The addition of modified carbon black shows bound rubber, thermal properties, and mechanical properties such as tensile strength, elongation at break and modulus 300% on the vulcanisate produced were increased from the vulcanisate that had been filled with N660 natural (N660-N). Keywords: natural rubber, carbon black, particle size, sonofication, characterisation


2011 ◽  
Vol 399-401 ◽  
pp. 561-564 ◽  
Author(s):  
Ping An Liu ◽  
Qing Song Yang ◽  
An Ze Shui ◽  
Hui Wang ◽  
Xiao Su Cheng ◽  
...  

A new synthesis technology of titanium carbide with microwave is introduced in this article. Microwave synthesis technology is a fast and relatively low temperature of synthesis method. Nano-titanium carbide powders were synthesized by carbothermal reduction of titanium dioxide and carbon black with the microwave synthesis method at 1100°C-1400°C in argon gas atmosphere. Nano-TiO2powder and carbon black were used as raw materials. The TiC powders were characterized with the XRD and TEM. The experimental results show that the synthesis rate is quick, even at relatively low synthesis temperature. The average particle size of the TiC powders synthesized by the microwave synthesis technology under low temperature (<1300°C) is less than 50nm, and the average particle size augments with increasing the microwave synthesis temperature and time.


1968 ◽  
Vol 41 (2) ◽  
pp. 373-381 ◽  
Author(s):  
Merton L. Studebaker

Abstract Resistance to treadwear is dependent upon the particle size, ultimate composition and “structure” of the carbon black used for reinforcement. Under moderate service conditions, reinforcement, as measured by treadwear index, is dominated by particle size. Under severe test conditions, the “structure” of the carbon black makes a very important contribution to the treadwear index. Groove cracking is quite dependent on the nature of the elastomer. Reversals in the effects of the nature of the crosslink, carbon black structure and particle size on groove cracking have been observed when the elastomer is changed from natural rubber to SBR.


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