Polymer composites combining different fillers

Two or more different filler types are utilized in the case of multi-component compounding, which produces very famous hybrid structures where effects of the different materials or components are combined. " Recent investigations on composites having multi-component filler systems have focused mainly on thermoplastic and thermoset polymers and not so familiar with rubbery materials. In most of the applications, CB and silica have been used... 

The interfacial acid-base function theory was put forward the first time in 1962 by Fowks. This theory holds that the filler and polymer matrix of a composite material can be treated as a generalized acid or alkali. When the surfaces of the filler and polymer matrix have different acids or alkalis, they are easy to combine. The greater their difference in pH, the more easily they will combine. When the surfaces of the filler and polymer matrix have the same acid or alkali, the surface of the filler should be modified to change its pH value. The different surface pH values are beneficial to improve the bonding strength between the reinforced material and polymer matrix and improve the performance of filled plastics. 

Polymer/mbber nanocomposites exhibit enhanced mechanical, thermal stability, toughness, stiffness, and gas-barrier properties compared to those of conventional composites at same filler volume fraction [11-15]. The interaction between the filler and polymer matrix of nanocomposites at the nanometer scale enables the formation of molecular bridges in the polymer matrix. This is the basis for the enhanced mechanical properties of nanocomposite as compared to conventional microcomposites [16, 17]. Nanocomposites containing hybrid fillers add a new dimension to the above enhanced properties. These composites show more advantages to composites containing single filler as the property of the hybrid filler composite depends upon the combined effect of individual filler. The nonlinear viscoelastic behavior of nanocomposites can be influenced differently by hybrid fillers than single filler. 

PHBV. Strong fiber-matrix attachment and good dispersion of filler in the host matrix were observed in all three composites. However, at higher filler concentrations, selfassociation of fibers severely deteriorated membrane properties. Figure 6.6 shows the different morphologies of PHBV composites with different cellulose contents. This study demonstrated that cellulose fibers could be used to enhance barrier properties of certain biopolymers, as permeability in composite films was significantly less than that in neat polymers. Biodegradable polymer matrices combined with purified... 

Composites consist of two (or more) distinct constituents or phases, which when combined result in a material with entirely different properties from those of the individual components. Typically, a manmade composite would consist of a reinforcement phase of stiff, strong material, embedded in a continuous matrix phase. This reinforcing phase is generally termed as filler. The matrix holds the fillers together, transfers applied loads to those fillers and protects them from mechanical damage and other environmental factors. The matrix in most common traditional composites comprises either of a thermoplastic or thermoset polymer [1]. 

Choudhury et al. [86] have studied the effect of polymer-solvent and clay-solvent interaction on the mechanical properties of the HNBR/sepiolite nanocomposites. They chose nine different sets of solvent composition and found that chloroform/methyl ethyl ketone (Qi/MEK) (i.e., HNBR dissolved in Ch and sepio-lite dissolved in MEK) is the best solvent combination for improvement in mechanical properties. XRD, AFM, , and UV-vis spectroscopy studies show that the dispersion of clay is best in the Ch/MEK solvent combination and hence polymer-filler interaction is also the highest. images shown in Fig. 14a, b clearly elucidate the aforementioned phenomena. Consequently, the tensile strength and modulus are found to be higher (5.89 MPa and 1.50 MPa, respectively) for the Ch/MEK system due to the minimum difference in interaction parameter of HNBR-solvent (xab) and sepiolite-solvent (Xcd)- Choudhury et al. have also studied the effect of different nanoclays [NA, , 15A, and sepiolite (SP)] and nanosilica (Aerosil 300) on the mechanical properties of HNBR [36]. The tensile... 

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