Filler solid particle

An important consideration is the effect of filler and its degree of interaction with the polymer matrix. Under strain, a weak bond at the binder-filler interface often leads to dewetting of the binder from the solid particles to formation of voids and deterioration of mechanical properties. The primary objective is, therefore, to enhance the particle-matrix interaction or increase debond fracture energy. A most desirable property is a narrow gap between the maximum (e ) and ultimate elongation ch) on the stress-strain curve. The ratio, e , eh, may be considered as the interface efficiency, a ratio of unity implying perfect efficiency at the interfacial Junction. 

Organotitanates form regular adsorbed layers on the filler surfaces. This assures a high degree of dispersibility of the solid particles of the filler, removal of moisture and air from the surfaces, a material improvement of the rheological properties of filled compositions. Also, it is possible to use much greater percentages of cheap... 

The interaction effect between a dispersion medium and a filler on the net-formation in a filled polymer melt is mostly visuallized in the fact that the finishing treatment of the surface of solid particles results in a significant change of the position of the flow curve of the filled polymer on the whole, and yield stress as well [5, 8-10]. 

This diagram essentially reflects the main features of variation of viscosity properties of a liquid when solid particles of a filler is introduced into it. It remains to impart a quantitative form to these features. This form is based on a great number of theoretical and experimental papers, which made it possible to formulate fundamental concepts in this field. 

Anisodiametrical particles of filler appearance of anisotropy of properties and relaxation phenomena, determined by the turn of solid particles in a flow... 

Exfoliating layered particles such as the clays, mica, or graphite is being used to provide very effective reinforcement of polymers at loading levels much smaller than in the case of solid particles such as carbon black and silica.77 81 Other properties can also be substantially improved, including increased resistance to solvents, and reduced permeability and flammability. A number of such studies specifically address the effects of introducing layered fillers into polysiloxanes 42,82 88... 

In a search for the defining structural parameter of a composite, the free volume of disperse system proved to be the most sound one from the physical standpoint Presumably, for disperse systems the free volume is a measure of the mobility of filler particles, just as for liquids it is a measure of the mobility of molecules. But as applied to highly-loaded coarse systems of the type solid particles — liquid — gas this notion requires a certain correction. In characterizing the structure of such specific systems as highly-loaded coarse composites, it should be noted that to prevent their settling and separation into layers under the action of vibration, the concentration of the finest filler fraction with the largest specific surface in dispersion medium should be the maximum possible. Because of this and also because of the small size of particles (20-40 pm), the fine fraction suspended in the dispersion medium practically does not participate in the formation of the composite skeleton, which consists of coarser particles. Therefore... 

The concept of the free volume of disperse systems can also be correlated with the change in the structure of the composite of the type solid particles — liquid — gas during its compaction. In that case the value of the maximum packing fraction of filler (p in Eq. (80b) remains valid also for systems containing air inclusions, and instead of the value of the volume fraction of filler, characteristic for a solid particles — liquid dispersion-system solid particles — liquid — gas should be substituted. This value can be calculated as follows the ratio of concentrations Cs x g/Cs, to the first approximation can be substituted by the ratio of the densities of uncompacted and compacted composites, i.e. by parameter Kp. Then Eq. (80b) in view of Eq. (88), for uncompacted composites acquires the form ... 

The first step in the preparation is to mix the filler particles with the reaction mixture containing the polymers, the cross-linking agent, and the catalyst. The second step is to stabilize the system in order to avoid aggregation and sedimentation of the solid particles. 

C(/SiC-BN composites and C(/SiC-ZrC composites were fabricated to improve the oxidation resistance and high temperature performance of C /SiC composites through the modification of matrix. SiC-BN matrix was formed through an in-situ reaction of active filler boron and protective gas N2 in the active-filler-controlled polymer pyrolysis (AFCOP). The oxidation performance of C(/SiC-BN composites was greatly improved when oxidized at 1000°C compared to that of C /SiC composite. Meanwhile, SiC-ZrC matrix was fabricated using the ZrC particles as inert filler. Both C(/SiC-BN composites and Ci/SiC-ZrC composites show non-catastrophie ftaeture behavior. The microstructures were also characterized by SEM and EDS. It was shown that the fiber reinforcement hindered the impregnation of solid particles into the fiber bundles so that most of the fillers remained in the inter-bundle matrix and most of the intra-bundle matrices were composed of Sic that resulted from the decomposition of polycarbosilane (PCS). 

The presence or absence of a yield stress is of great importance in the molding of filler filled or fiber reinforced polymers, and also for the physical stability of many industrial products. Casson proposed an equation describing the steady state shear flow properties of the suspensions of solid particles in Newtonian liquids (Casson, 1959), so as to easily evaluate yield stresses ... 

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