Surface energy of fillers

Aid in the uniform dispersion of additives. Make powdered solids (e.g. particulate fillers with high energy and hydrophilic surface) more compatible with polymers by coating their surfaces with an adsorbed layer of surfactant in the form of a dispersant. Surface coating reduces the surface energy of fillers, reduces polymer/filler interaction and assists dispersion. Filler coatings increase compound cost. Fatty acids, metal soaps, waxes and fatty alcohols are used as dispersants commonly in concentrations from 2 to 5 wt %. 

The equation of state. Eg. (10), can also be employed for determining the surface energy of fillers. Examples for the fillers investigated are an N330 carbon black and an attrited N330 carbon black. The attrition process of the carbon black used consists of two parts. We first heat the carbon black in a vacuum oven at 150 C for 24 hours. We then ball-milled the carbon black at 25 -225 C for 48 hours. The amount of carbon black put into the ball mill container was about one third of the volume of the container. 

The Surface energy of filler and matrix are important for the adhesion properties in composites. By calculation of the surface free energy of the composite components from Contact angle measurement, Inverse gas chromatography (IGC) or other measurements, adhesion parameters can be estimated and controlled if necessary, for particular applications. An illustration of this is given in this article. 

Wolff, S. Wang, J. (1992). Filler— Elastomer Interactions. Part IV. The Effect of the Surface Energies of Fillers on Elastomer Reinforcement. Rubber Chemistry and Technology, 65, 329-342. 

Pretreating the surface of fillers can reduce the surface energy of fillers, which can prevent the aggregation. 

Eq 2.71, expressing the interaction force as a function of surface energy of the filler and the ratio of surface energies of filler and matrix, is applicable to the systems adhering through physical interactions typically failing at the filler-matrix interface. 

In general, the theoretical calculations meet the experimental data. One can also suppose that in real systems, the appearance of the maximum of the losses corresponding to the polymer in the surface layer is determined by the chain flexibility, cohesion energy of the polymer, and surface energy of filler. 

The adsorption of gas onto a solid surface can also be used to estimate surface energy. Both inverse gas chromatography (IGC) and isotherm measurement using the BET method [19] have been used. Further discussion and detailed references are given by Lucic et al. [20] who compare the application of IGC, BET and contact angle methods for characterising the surface energies of stearate-coated calcium carbonate fillers. 

The reduction in filler-filler interaction due to acetylene-plasma treatment is obviously due to the lower surface energy of the coated carbon black. The carbon black shows an appreciable reduction in surface energy after the plasma treatment, towards the range of the polymer S-SBR. This results in a better wetting of the filler particles by the elastomer [53, 54]. 

The reinforcement of filled rubbers is usually determined by the particle size and the surface characteristics of filler particles 1U U6). Recent studies have emphasized an important role of internal energy effects in reinforcement29). Hence, thermomechanical measurements provide a very important approach to the study of such reinforcement. 

When the behavior of carbon black and silica is compared in compounded rubber, it is evident that silica adsorbs less rubber than carbon black. In addition to the differences in the chemical compositions of the surfaces this difference is caused by the differences in the dispersive components of surface energies of each filler. Car-... 

This energy balance depends on the energy of the applied strain and the energy of surface. We have consistently assumed that the energy input is lower than the cohesive energy of filler particles. But this is not always true. ... 

CaCO EPR rubber rubber silicone maleates fatty acid silanes PDMS decreased disperse component of the surface energy filler surface energy approaches surface energy of matrix decreased tensile strength and flexural cracking increased green strength, Mooney viscosity, and tensile properties surface hydrophobization resistance to solvent extraction and water 21 49 49 37... 

Applications. The following uses of contact angle were reported in the literature surface energy of different sizes for fibers, correlation between contact angle of fiber and interlaminar shear strength of composite, effect of surface treatment of fillers for paints, the matrix-filler adhesion parameter for PS filled with CaCO, dispersion stability of PEO-modified kaolin particles, determination of contact angle of carbon fibers and its dependence on treatment, wettability of fiber sur-... 

Special considerations chemical composition of filler surface affects nucleation of filler traces of heavy metals decrease thermal stability and cause discoloration siuface free energy of fillers determines interaction large difference in thermal properties of fillers and polymer may cause stress hydrotalcite is used as acid neutralizer with stabilizing packages anatase titanium dioxide decreases UV stability presence of transition metals (Ni, Zn, Fe, Co) affects thermal and UV stability calcium carbonate and talc were found to immobilize HALS stabilizers in PP with organic masterbatches such as ethylene diamine phosphate V-0 classification can be obtained with 20-25 wt%, at the same time tensile strength and impact strength are substantially reduced... 

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