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

1962 ◽  
Vol 35 (3) ◽  
pp. 611-614 ◽  
Author(s):  
Oliver Dessewffy
Keyword(s):  
Natural Rubber ◽  
Temperature Dependence ◽  
Absolute Temperature ◽  
Low Energy ◽  
Extraction Temperature ◽  
Gel Structure ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Adsorption Energies ◽  
Adsorption Phenomena

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.

REINFORCEMENT OF NATURAL RUBBER BY SILICA/SILANE IN DEPENDENCE OF DIFFERENT AMINE TYPES

2017 ◽  
Vol 90 (4) ◽  
pp. 651-666 ◽  
Author(s):  
C. Hayichelaeh ◽  
L. A. E. M. Reuvekamp ◽  
W. K. Dierkes ◽  
A. Blume ◽  
J. W. M. Noordermeer ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Natural Rubber ◽  
Health And Safety ◽  
Aliphatic Amines ◽  
Shielding Effect ◽  
Processing Temperature ◽  
Rubber Content ◽  
Payne Effect ◽  
Rubber Compounds ◽  
Bound Rubber

ABSTRACT Diphenyl guanidine (DPG) is the most commonly used secondary accelerator in silica-reinforced rubber compounds because of its additional positive effect on the silanization reaction and deactivation of free silanol groups that are left over after the silanization. However, because of health and safety concerns about the use of DPG, which decomposes to give highly toxic aniline during high processing temperature, safe alternatives are required. This work investigates the effect of various types of aliphatic amines having alkyl or cyclic structures and similar pKa (i.e., hexylamine [HEX], decylamine [DEC], octadecylamine [OCT], cyclohexylamine [CYC], dicyclohexylamine [DIC], and quinuclidine [QUI]) on the properties of silica-reinforced natural rubber (NR) compounds by taking the ones with DPG and without amine as references. When compared with the compound without amine, the use of all amine types reduces filler–filler interaction (i.e., the Payne effect) and enhances filler–rubber interaction, as indicated by bound rubber content and decreased heat capacity increment. The amines with alkyl chains can reduce the Payne effect and enhance cure rate to a greater extent compared with the amines with cyclic rings as a result of better accessibility toward the silica surface and a shielding effect because of less steric hindrance. The longer carbon tails on linear aliphatic amines ranging from HEX, DEC, to OCT lead to a lower Payne effect, lower heat capacity increment, higher bound rubber content, and higher modulus as well as tensile strength. Overall, the use of OCT provides silica-reinforced NR compounds with properties closest to the reference one with DPG and can act as a potential alternative for DPG.

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

1962 ◽  
Vol 35 (3) ◽  
pp. 599-610 ◽  
Author(s):  
Oliver Dessewffy
Keyword(s):  
Heat Treatment ◽  
Carbon Black ◽  
Critical Concentration ◽  
Physicomechanical Properties ◽  
Extraction Temperature ◽  
Linear Character ◽  
Clear Cut ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Degree Of Degradation

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.

ANALYSIS OF CARBON BLACK–REINFORCED CARDANOL-MODIFIED NATURAL RUBBER COMPOUNDS

2015 ◽  
Vol 88 (2) ◽  
pp. 289-309 ◽  
Author(s):  
Sunita Mohapatra ◽  
Golok Bihari Nando
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Multifunctional Additive ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Link Density ◽  
Polycyclic Aromatic ◽  
Cross Link Density ◽  
Filler Dispersion ◽  
Better Than

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.

Influence of Fillers Surface Characteristics on Bound Rubber Properties of Filled Natural Rubber Compounds

2013 ◽  
Vol 845 ◽  
pp. 412-416 ◽  
Author(s):  
Mustafa Kamal Mazlina
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Surface Activity ◽  
Specific Activity ◽  
Filler Particle ◽  
Surface Characteristics ◽  
Rubber Content ◽  
Rubber Compounds ◽  
Bound Rubber ◽  
Service Application

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

Scalable Approach to High Coverages on Oxides via Iterative Training of a Machine-Learning Algorithm

2019 ◽  
Author(s):  
Andrew Medford ◽  
Shengchun Yang ◽  
Fuzhu Liu
Keyword(s):  
Machine Learning ◽  
Chemical Potential ◽  
Learning Algorithm ◽  
Absolute Error ◽  
Low Energy ◽  
Training Data ◽  
High Coverage ◽  
Metal Compounds ◽  
Adsorption Energies ◽  
The Stability

Understanding the interaction of multiple types of adsorbate molecules on solid surfaces is crucial to establishing the stability of catalysts under various chemical environments. Computational studies on the high coverage and mixed coverages of reaction intermediates are still challenging, especially for transition-metal compounds. In this work, we present a framework to predict differential adsorption energies and identify low-energy structures under high- and mixed-adsorbate coverages on oxide materials. The approach uses Gaussian process machine-learning models with quantified uncertainty in conjunction with an iterative training algorithm to actively identify the training set. The framework is demonstrated for the mixed adsorption of CH<sub>x</sub>, NH<sub>x</sub> and OH<sub>x</sub> species on the oxygen vacancy and pristine rutile TiO<sub>2</sub>(110) surface sites. The results indicate that the proposed algorithm is highly efficient at identifying the most valuable training data, and is able to predict differential adsorption energies with a mean absolute error of ~0.3 eV based on <25% of the total DFT data. The algorithm is also used to identify 76% of the low-energy structures based on <30% of the total DFT data, enabling construction of surface phase diagrams that account for high and mixed coverage as a function of the chemical potential of C, H, O, and N. Furthermore, the computational scaling indicates the algorithm scales nearly linearly (N<sup>1.12</sup>) as the number of adsorbates increases. This framework can be directly extended to metals, metal oxides, and other materials, providing a practical route toward the investigation of the behavior of catalysts under high-coverage conditions.

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