Composite characteristics interfacial interactions

Although a number of filler characteristics influence composite properties, particle size, specific surface area, and surface energetics must again be mentioned here. All three also influence interfacial interactions. In the case of large particles and weak adhesion, the separation of the matrix/ filler interface is easy, debonding takes place under the effect of a small external load. Small particles form aggregates which cause a deterioration in the mechanical properties of the composites. Specific surface area, which depends on the particle size distribution of the filler, determines the size of the contact surface between the polymer and the filler. The size of this surface plays a crucial role in interfacial interactions and the formation of the interphase. 

In this paper, a molecular thermodynamic approach is developed to predict the structural and compositional characteristics of microemulsions. The theory can be applied not only to oil-in-water and water-in-cil droplet-type microemulsions but also to bicontinuous microemulsions. This treatment constitutes an extension of our earlier approaches to micelles, mixed micelles, and solubilization but also takes into account the self-association of alcohol in the oil phase and the excluded-volume interactions among the droplets. Illustrative results are presented for an anionic surfactant (SDS) pentanol cyclohexane water NaCl system. Microstructur al features including the droplet radius, the thickness of the surfactant layer at the interface, the number of molecules of various species in a droplet, the size and composition dispersions of the droplets, and the distribution of the surfactant, oil, alcohol, and water molecules in the various microdomains are calculated. Further, the model allows the identification of the transition from a two-phase droplet-type microemulsion system to a three-phase microemulsion system involving a bicontinuous microemulsion. The persistence length of the bicontinuous microemulsion is also predicted by the model. Finally, the model permits the calculation of the interfacial tension between a microemulsion and the coexisting phase. 

Mechanical Tensile Studies. The simple stress vs. strain characteristics of two-phase materials and their variation with relative phase composition can usually be given straightforward interpretation in terms of critical underlying structural factors. Among these factors can be listed topological connectivily of, and interfacial interaction between the phases. 

The formation of composite, but not mechanical mixture of components, confirms the results of EDX and FTIR spectroscopy. Moreover, the shift of characteristic bands in the FTIR spectra of composites samples confirms the presence of strong interfacial interaction between polymeric macromolecules and surface of TiO -S nanoparticles in the result of H-bonding. 

Carbon-based polymer nano composites represent an interesting type of advanced materials with structural characteristics that allow them to be applied in a variety of fields. Functionalization of carbon nanomaterials provides homogeneous dispersion and strong interfacial interaction when they are incorporated into polymer matrices. These features confer superior properties to the polymer nanocomposites. This chapter focuses on nanodiamonds, carbon nanotubes and graphene due to their importance as reinforcement fillers in polymer nanocomposites. The most common methods of synthesis and functionalization of these carbon nanomaterials are explained and different techniques of nanocomposite preparation are briefly described. The performance achieved in polymers by the introduction of carbon nanofillers in the mechanical and tribological properties is highlighted, and the hardness and scratching behavior of the nanocomposites are also discussed. 

Fillers are those materials added to a matrix in order to improve its properties. The filler characteristics that affect the composite s properties are particle size, size distribution, specific surface area and particle shape and interfacial interactions. The shape of most mineral filler particles can be approximated as a sphere, cube, block, plate, needle or fibre. Some fillers contain a mixture of shapes. ... 

One important application of the UV-laser treatment is the activation of polymeric fiber surfaces for improved fiber/resin interfacial interaction in fiber-reinforced composites or advanced composites [126-128]. As shown in Tables 20.2 and 20.3, the laser treatment environment has a clear effect on the surface chemistry and acid-base characteristics, as well as, the resulting IFSS in the composite. It is obvious there is an excellent correlation between the acid-base component of the surface energy and the IFSS [129]. 

The optimization of the interfacial bond between the particle and the matrix, can allow the tailoring of the properties of the overall composite, as done in macrocomposites. Therefore, a good adhesion at the interface will improve many material properties, such as shear strength, corrosion resistance, delamination resistance, fatigue and, by extension, the fracture characteristics of the composite. Just as some nanocomposites may exhibit properties that are predominately dependent on the interfacial interactions there are others that may show the quantum effects associated with nano-dimensional structures. 

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