Dependence of Bound Rubber on Concentration of Filler and on Temperature. I

1962 ◽  
Vol 35 (3) ◽  
pp. 599-610 ◽  
Author(s):  
Oliver Dessewffy

Abstract The change in quantity of rubber gel with the concentration of carbon black in filled natural rubber compounds was studied. It was established that there is a linear relationship between the amount of rubber gel and the black concentration, within a range of 20 to 80 parts of black to 100 parts by weight of rubber. No clear-cut relation exists between the quantities of rubber gel or the constants for the linear relations and the physicomechanical properties of the vulcanizates. The factors upon which the amount of bound rubber depend, i.e., the degree of degradation of the rubber, the heat treatment of the mixtures and the extraction temperature, do not alter the linear character of the cited relation. The critical concentration of certain types of blacks was determined. Up to this concentration no coherent rubber/black gel system is formed. The critical values for the black concentration are clearly related to some of the elastic properties of the filled vulcanizate.

2015 ◽  
Vol 294 (3) ◽  
pp. 501-511 ◽  
Author(s):  
Dina Gabriel ◽  
Alexander Karbach ◽  
Doris Drechsler ◽  
Jochen Gutmann ◽  
Karlheinz Graf ◽  
...  

1987 ◽  
Vol 60 (1) ◽  
pp. 14-24 ◽  
Author(s):  
S. Shiga

Abstract The relationship between the molecular weight, the bound rubber, and the PI value was studied for EPR, of which the molecular structure was measured with GPC-LALLS. A strong linear correlation is found between the bound rubber and the PI value. The Meissner theorem, modified to express a severer dependence of the bound rubber on the molecular weight than the original theorem expects and the use of a molecular size instead of the molecular weight, can explain the relationship between the molecular weight and the bound rubber, accordingly the PI value. They indicate not only the dependence of mixing processability on polymer adsorption, but also strongly suggest the mechanism of carbon black dispersion that aggregates are scraped out from the surface of agglomerates as illustrated by the onion model. A pulsed NMR was used to measure the spin-spin relaxation time T2 of EPR in rubber compounds of different mixing time to study the rubber phase structure and its time change. It can be imagined from the T2-time curves that till tmin, polymer molecules are rapidly bound on the carbon black surface to become thick gradually, while adsorbed segments per a molecule increase with time. After tmin, gradual rearrangement of molecules on the surface and the biphasic structure of the bound rubber may proceed. The whole thickness of the bound rubber increases gradually even after tmin. The resistance against the dispersion of carbon black seems to be strengthened with mixing time.


1962 ◽  
Vol 35 (3) ◽  
pp. 611-614 ◽  
Author(s):  
Oliver Dessewffy

Abstract The dependence of the quantity of gel rubber on the extraction temperature was studied, for black-filled natural rubber compounds. Results show that the logarithm of the specific rubber gel quantity increases linearly with the reciprocal of the absolute temperature within a range of 25 to 80° C. The adsorption energies were calculated on the basis of the temperature dependence. The low energy values determined in this fashion supported the assumption that the bondings of the gel structure are largely “weak” bonds of a physical character. The author seeks to explain the observed adsorption phenomena by certain hypotheses.


2015 ◽  
Vol 88 (2) ◽  
pp. 289-309 ◽  
Author(s):  
Sunita Mohapatra ◽  
Golok Bihari Nando

ABSTRACT Carbon black is advantageous for rubber as a reinforcing filler. Carbon blacks at higher loadings require process aids for easier processing and improved filler dispersion. Aromatic oils have been used so far in the rubber industry as plasticizer and process aids. The presence of polycyclic aromatic hydrocarbons in these oils has raised concerns, and they have been banned. Rubber industries are looking for alternate sources of process aids from renewable resources. Cardanol (m-pentadecenyl phenol), an agricultural by-product of the cashew industry, is cheap and abundantly available. It was proved recently to be a plasticizer and a multifunctional additive. The dispersion of carbon black in natural rubber (NR) grafted chemically with cardanol (CGNR) is investigated and compared with that of oil plasticized natural rubber. The physico-mechanical properties of the carbon black–filled CGNR vulcanizates are better than that of the aromatic oil plasticized NR vulcanizates. The cross-link density and bound rubber content are higher and the Payne effect is lower for the carbon black–filled CGNR vulcanizates as compared with oil plasticized NR vulcanizates. Dispersion of carbon black in the CGNR matrix is uniform and better than the aromatic oil plasticized NR.


2013 ◽  
Vol 845 ◽  
pp. 412-416 ◽  
Author(s):  
Mustafa Kamal Mazlina

One of the most important phenomena in rubber science is the reinforcement by rigid entities, such as carbon black, clays, silicates and calcium carbonate. Thus, these fillers are added to rubber formulations to optimise properties that meet a given service application or set of performance parameters. Fillers can be divided into three categories reinforcing, semi-reinforcing and non-reinforcing. For a given elastomer and state of mix, bound rubber can be considered as a measurement of a surface activity of a filler and is considered as one of major factors in reinforcement. A strong rubber: filler interaction results in a large bound rubber content. Good dispersions and distribution of filler aggregates is also important for the full reinforcing potential of fillers to be reached. In this study, the influence of fillers on bound rubber content of Natural Rubber compounds were determined and compared. Results showed that the bound rubber content followed the trend of Carbon Black>Silica>Carbon Black>Starch. The two main filler characteristics that affect the bound rubber properties are the filler particle size and surface activity. The specific activity of the filler is determined by the physical and chemical nature of the filler surface in relation to that of elastomer. Keywords: reinforcement, surface energy


2017 ◽  
Vol 59 (11-12) ◽  
pp. 1054-1060 ◽  
Author(s):  
Mohan Kumar Harikrishna Kumar ◽  
Subramaniam Shankar ◽  
Rathanasamy Rajasekar ◽  
Pal Samir Kumar ◽  
Palaniappan Sathish Kumar

2020 ◽  
Vol 39 (1) ◽  
pp. 81-90
Author(s):  
An Zhao ◽  
Xuan-Yu Shi ◽  
Shi-Hao Sun ◽  
Hai-Mo Zhang ◽  
Min Zuo ◽  
...  

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