Polymer nanocomposites composition relationships

Synthetic composite materials have passed through intensive progress in the last fifty years. Originally, synthetic polymers were blended with inorganic fillei-s for the sake of price reduction on the other hand, fillers cause considerable change in many physical properties of polymei-s. Later, functional fillers bringing other effects to polymer composites, such as magnetic or electrical properties, bioactivity, reduced flammability, etc., were introduced in the 80 s and 90 s. Nanocomposites can offer both miique properties and multi-functionality, which are well applicable in various fields. Undoubtedly, if one wants to use polymer nanocomposites in specific applications, the structure-property relationships have to be fully understood in these miique materials first. 

A model was introduced that describes the montmorillonite as flexible. This flexibility could result in various configurations other than flat sheets, particularly at dimensions larger than 16 nm. More USAXS work of polymer-montmorillonite nanocomposites needs to be performed before any definite relationships can be established for long-range order in polymer-montmorillonite composites. 

Polyesters provide the option of nanocomposites prepared with crystalline and amorphous continuous phases. The crystalline polymers behave in a similar way to the polyamides (nylons) as regards structure-property relationships. The amorphous polymers are a different matter. What is unexplained by first-principle arguments is the dramatic increase in percent elongation to failure [39,45,59] observed with amorphous polymer-montmorillonite composites. This phenomenon also applies to elastomers. 

The first report on the preparation of a CNT/polymer nanocomposite in 1994 [2], a myriad of research efforts have been made to understand their structure-property relationship and find useful applications. The effective utilization of carbon nanotubes in composite apphcations depends strongly on the ability to homogeneously disperse them throughout the matrix without destroying their integrity. Furthermore, good interfacial bonding... 

This issue of specific surface area hints at how one might change the nature of reinforcement. In typical micro- and macrocomposites, the properties are dictated by the bulk properties of both the matrix and the flUer. This relationship between the properties of the composite and the properties of the filler is what leads to the stiffening and degraded elongation mentioned earlier. In the case of nanocomposites, the properties of the material are instead tied to the interface. Terms like bound polymer, bound rubber, and interphase have been used to describe the polymer at or near the interface, where significant deviations from bulk structure and properties are known to occur (Fig. 6.2). 

The characterization methods used in the analysis of the chemical structure, microstructure, and morphology as well as the physical properties of the nanocomposites are varied. Many of these techniques are specific for characterization of particular properties of nanocomposites, and the properties of nanocomposites are also correspondingly discussed. To fully understand the structure-property relationships, several characterization techniques are often used. The properties of the polymer blend nanocomposites strongly depend on their composition, size of the particles, interfacial interaction, etc [35],... 

Formulating BMIs as matrices for composites and hybrid materials is another effective approach. The use of micro- and nanometer scale fillers allowed materials with new or improved properties. Studies of interactions at the interface among nanometric particles and a multicomponent polymer matrix have indicated that the interface itself can be equally important as the individual components regarding the overall effects because not all the principles from macro- and microscale can be used to explain the properties and behavior of nanocomposites. Combining these methods provides the ability to tailor and control the overall composition of these new materials, their structure (nanostructure, as well as supramolecular architecture), and also allows tunable properties by tunable structure-property relationship. 

---