Inorganic particle-polymer

Q Fu, G Wang. Polyethylene toughened by rigid inorganic particles. Polym Eng Sci 32 94-97, 1992. 

A nanocomposite material can be defined as one that consists of two or more different material components, at least one of which has a domension (i.e., length, width, or thickness) below 100 nm. There are many types of nanocomposites presently under research and development including polymer/ inorganic particle, polymer/polymer, metal/ceramic, and inorganic-based nanocomposites. However, the first named one, commonly called polymer nanocomposite (PNC) and defined as the combination of a polymer matrix resin (continuous phase) and inclusions having at least one dimension less than 100 nm, is the only type of nanocomposite to date that has seen any significant commercial activity. 

In some systems, such as lake and river waters, the suspended inorganic particles may be coated by biological polymers, termed humic substances, which prevent flocculation by either steric or electrostatic mechanisms. These can also interact with added inorganic salts (31) that can neutralize charged functional groups on these polymers. 

This equation is based on the assumption that pseudoplastic (shear-thinning) behaviour is associated with the formation and rupture of structural linkages. It is based on an experimental study of a wide range of fluids-including aqueous suspensions of flocculated inorganic particles, aqueous polymer solutions and non-aqueous suspensions and solutions-over a wide range of shear rates (y) ( 10 to 104 s 1). 

Commonly, roughness can be tailored by using additives. These are mainly based on combinations of inert, inorganic particles of different sizes and the weight ratio of large to small particle sizes. These particles should be well dispersed in the base film to prevent abrasion, which is influenced by the particle shape and the kind of embedding in the polymer matrix. The affinity of these particles to the solid polymer seems to be based on adhesion of the melt to the solids and to cohesive forces in the solid state. This phenomenon, however, has not yet been explored in sufficient detail. 

Plasma Polymerization. Plasma-induced polymerization (24) of vinyl monomer from inorganic particles is also employed for polymer grafting. The conventional reactors for liquid-phase polymerization of vinyl compounds after generation of plasma on inorganic particles or powders have been recently invented by Ikeda et al. (25). Haraguchi et al. (26) have also prepared polymer-modified silica by plasma-induced polymerization of glycidyl methaciylate. 

Scheme 12.1.4 Reaction of inorganic particle with chemically active polymer.

The reaction of hydroxyl group on inorganic particles with reactive polymers having isocyanate (27.28), alkoxysilane (29,30), and chlorosilane (29) groups efficiently gave the polymer-grafted particles [Reactions (9) and (10)]. 

Fig. 12.1.5 Polymer encapsulation of inorganic particles by polymerization of adsorbed surface active monomer.

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