Method for the assessment of the degree of pigment or carbon black dispersion in polyolefin pipes, fittings and compounds

2015 ◽  
Keyword(s):  
Carbon Black ◽  
Carbon Black Dispersion

States of Carbon Black Dispersion and Extensibility of Rubbers

1993 ◽  
Vol 66 (2) ◽  
pp. 317-328 ◽  
Author(s):  
Asahiro Ahagon
Keyword(s):  
Carbon Black ◽  
Tensile Property ◽  
Crosslink Density ◽  
Hydrodynamic Effect ◽  
Property Variation ◽  
Agglomerate Size ◽  
Filled Rubber ◽  
Two Temperatures ◽  
Confined Polymer ◽  
Carbon Black Dispersion

Abstract Analysis is made for the origin of the mixing-induced tensile property variation of a filled rubber. Attention is paid to the hydrodynamic effect f(ϕe) of the filler, defined here as the factor to adjust the deviation of 100% modulus from the theory of rubber elasticity. For the rubbers mixed under variety of conditions, the f(ϕe)'s are calculated from the observed values of the modulus, at 25°C and 100°C, and the crosslink density. The variation of the f(ϕe) is considered to be governed by the mobility of the polymer confined in agglomerates of the filler. The mobility variation due to mixing seems to be mainly influenced by agglomerate size at 25°C, and by agglomerate size and chemical constraints at 100°C. Therefore, the f(ϕe)'s at the two temperatures are suggested to be useful measures of the state of carbon-black micro-dispersion. The extensibility of the rubbers is closely related f(ϕe). This indicates that the failure property is also governed by the mobility of the confined polymer.

Reflectometry—A New Method of Measuring Filler Dispersion

1998 ◽  
Vol 71 (1) ◽  
pp. 17-25 ◽  
Author(s):  
M. Gerspacher ◽  
L. Nikiel ◽  
H. H. Yang ◽  
C. P. O'Farrell
Keyword(s):  
Carbon Black ◽  
Sample Preparation ◽  
New Method ◽  
Standard Equipment ◽  
Rubber Sample ◽  
Filler Dispersion ◽  
Sample Measurement ◽  
Carbon Black Dispersion

Abstract A new method of measuring carbon black dispersion in rubber is presented. This method is based on the measurement of the light reflectivity from the rubber sample using standard equipment used in the evaluation of the tint strength of carbon black (ASTM D3265 procedure). This method can be applied for both uncured and cured samples; however, the uncured sample measurement has significant advantages in the simplicity of the sample preparation and obtaining important filler dispersion information of the compound. It is shown that samples with better dispersed carbon black reflect less light as compared to samples with poor carbon black dispersion.

Contributions of Elastomer Behavior to Mechanisms of Carbon Black Dispersion

1984 ◽  
Vol 57 (1) ◽  
pp. 153-167 ◽  
Author(s):  
N. Nakajima ◽  
E. R. Harrell
Keyword(s):  
Carbon Black ◽  
Effective Means ◽  
High Stress ◽  
Flow State ◽  
Breakdown Mechanism ◽  
Roll Mill ◽  
Highly Stretchable ◽  
Internal Mixer ◽  
Region Ii ◽  
Carbon Black Dispersion

Abstract In order to achieve good mixing of elastomer and carbon black, the elastomer domains must be reduced in size, that is, the elastomer must be broken into smaller pieces. If this is the only requirement, Region I of the Tokita-White scheme may be most preferred, because the elastomer easily breaks up at this state. However, it is too stiff for compaction of the compound; that is, the elastomer is too stiff to conform to the complex topology of carbon black. If the compaction is the only requirement. Region IV is most preferred, because the material is in the melt-flow state. In reality, Region II, the rubbery, highly stretchable state gives the best result. It appears that the use of Region II is a compromise. However, there is a more important reason for the preference of Region II, that is, the effectiveness of this region for the breakdown of carbon black agglomerates. The breakdown mechanism involves elastomer as a medium for the transfer of force. The effectiveness of the elastomer medium depends on its ability to stretch with the development and maintenance of a high stress. The former may be characterized by the failure envelop and the latter by the stress relaxation experiments. In roll mill as well as internal mixer processing, the folding of compound and the subsequent stretching of it, e.g., lamination mechanism, are the effective means for carbon black dispersion. It is postulated that the lamination mechanism generates localized high shear fields, which force carbon black agglomerates to rotate in the high modulus medium; this results in peeling of the aggregates from the outer shells of the agglomerates.

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