Miscibility filler-matrix

The hydrophilic surface of the cellulose-based nanoreinforcements leads to poor interaction between matrix and the filler [29]. Furthermore, the chemical compatibility is very important in controlling the dispersion and the adhesion among them. Therefore, it is common to see weak filler-matrix interactions when hydrophilic whiskers were added to hydrophobic matrices [4]. The miscibility of cellulose nanofillers with hydro-phobic matrices can be improved by various surface modifications, for example, esterification and acylation. The increment in the filler/matrlx compatibility produces the enhancement of mechanical and thermal properties but also enhances the barrier properties [30]. 

The modification of theological properties also may be achieved by addition of a small amount of another polymer which is not miscible with matrix P0I3 -mer. Thus, the general conclusion may be drawn that the peculiarities of the rheological properties of filled polymers are determined by the combined action of various factors, namely, by hydrod3mamic effects, the interaction between the filler particle and a matrix, leading to the formation of the surface layers and the formation of the structural frame by the filler particles. 

The distribution of the reinforcement agent within the matrix can be very effectively impacted by the use of multiphase polymer blends. The microstructure morphology is determined by the polymer structure in the blend, the system composition and miscibility, which can lead to immiscible or co-continuous distribution of phases. (Utracki 1989). The incorporation of the filler into one of the polymer phases or into the phase interface has a strong influence on the electrical conductivity of composites, concomitantly reducing the percolation concentration. 

There are situations where polymer blends may exhibit unique characteristics for utility in composite systems. One of these examples involves the segregation of conductive carbon black at the interface of phase separated polymer blends to yield a much lower concentration to reach the percolation threshold [ 1098,1099 ]. Another area of interest involves the addition of a polymer offering excellent adhesion to the filler as well as mechanical compatibility (or miscibility) with the matrix polymer. The polymeric interfacial agent can offer improved dispersion of this filler in addition to improved stress transfer across the interface between matrix and filler. The preferential concentration of filler particles in one phase is a situation... 

Besides certain basic properties inherent to each polymer and closely related to its molecular structure, there are a number of properties that are secondary but can, however, affect the behavior of a material in a given function. These properties can be optimized or modified by means of the formulation—-that is, by incorporation of foreign substances that are miscible or immiscible with it into the raw polymer. The technical terminology distinguishes between additives and modifiers according to the proportion of these substances in the final material. Additives are used in low proportion (typically less than 5%) and do not affect the material mechanical properties, whereas modifiers such as plasticizers or fillers are added in higher proportions and even sometimes in majority. These substances are physically dispersed in the polymer matrix in order to modify certain characteristics without affecting the basic molecular structure of the polymer as well as its essential properties. 

---