Interaction polymer chains-sheets

Israelachvili and his colleagues have used the SEA to study the interactions between surface layers of surfactant and of other molecules representing functionalised polymer chains, adhesion promoters or additives. Typically a monolayer of the molecule concerned is deposited onto cleaved mica sheets. The values of surface energies obtained from the JKR equation (Eq. 18) throw some interesting light on the nature and roughness of surface layers in contact. 

If chemical treatment of the matrix polymer blend or the filler needs to be avoided or the interaction between the components is insufficient, then a third component, such as a polymer compatibilizer [20], can be added to the composite. Compatibilizers are added especially to polyolefin/nanoclay composites prepared by melt blending because the organo modification of the clay is seldom sufficient to create a favorable interaction between polymer chains and the clay sheets [21]. The interfacial adhesion between the compatibilizer and clay galleries is influenced by the functionality and its concentration, molecnlar weight and molecular weight distribution of the compatibilizer, and the mass ratio of the compatibilizer to the clay [22]. 

The composition calculated for a maximum packing density in terms of Fig. 6 and 7 coincides very well the analytical data of the polymer oxidized to its optimum conductivity. Some workers in the field favour an alteirnative structural model which consists again of sheets of polymer chains but with the zig-zag-plane in the plane of the sheet. This model is based on the assumption that there will be an appreciable interaction between the TT-electrons of the chain and the counterions, notably with I -ions in the case of iodine-oxidized poly(aceSylene).,48,49 the same time this model negates appreciable electronic interactions between adjacent chains. 

Kevlar owes its strength to the way in which the individual polymer chains interact with each other. The chains are hydrogen bonded, forming a sheet-like stmcture. 

A layered particle-reinforced bionanocomposite, also known as a layered polymer nanocomposite (LPN), can be classified into three subcategories depending on how the particles are dispersed in the matrix. Intercalated nanocomposites are produced when polymer chains are intercalated between sheets of the layered nanoparticles, whereas exfoliated nanocomposites are obtained when there is separation of individual layers, and flocculated or phase-separated nanocomposites are produced when there is no separation between the layers due to particle-particle interactions. This last class of composites is often named microcomposites as the individual laminas do not separate, thus acting as microparticles dispersed in the polymeric matrix. Their mechanical and physical properties are poorer than exfoliated and intercalated nanocomposites [17, 20, 21, 36, 37]. Figure 11.1 shows a schematic drawing of the structure of layered nanocomposites. 

---