Fillers oxygenated functions

Abstract Plasma polymerization is a technique for modifying the surface characteristics of fillers and curatives for rubber from essentially polar to nonpolar. Acetylene, thiophene, and pyrrole are employed to modify silica and carbon black reinforcing fillers. Silica is easy to modify because its surface contains siloxane and silanol species. On carbon black, only a limited amount of plasma deposition takes place, due to its nonreactive nature. Oxidized gas blacks, with larger oxygen functionality, and particularly carbon black left over from fullerene production, show substantial plasma deposition. Also, carbon/silica dual-phase fillers react well because the silica content is reactive. Elemental sulfur, the well-known vulcanization agent for rubbers, can also be modified reasonably well. 

Discussion - Some surface modification does take place on all carbon black samples. On the other hand, in the case of the oxidized gas black, its larger oxygen functionality clearly increases its capability to be modified. The case of carbon/ silica dual-phase fillers is similar. The TGA data show that the higher silica content... 

The physical properties of some fillers play a role in their function as stabilizers. A1(OH)3 undergoes endothermic decomposition which lowers temperature of material. Loss of water from MgiOH), may increase stability in some cases. In others, it may cause degradation. This is discussed below. The platelet structure of some fillers (e.g., talc or mica) contributes to an increased thermal stability because the degradation rate is increased as oxygen concentration increases. The structure formed by the platelets reduces the diffusion rate of oxygen. 

Relative oxygen permeability of nanocomposites with imidazolium modified montmorillonite as a function of filler volume fraction. The permeation behavior is compared with composites containing dioctadecyldimethylammo-nium ions [22] ( ) Ammonium and (a) Imidazolium composites. The dotted lines only serve as guides. (Reproduced from Mittal, V., Eur. Polym. /., 43, 3727, 2007. With permission from Elsevier.)... 

Mica flakes embedded in a polymer and properly oriented in a plane can provide a tortuous path to vapors and liquids, similarly to the natural composites shown in Figure 1.1. Barrier properties can be imparted in blow-molded containers, packaging films, and corrosion-resistant coatings not only by mica but also by other impermeable lamellar fillers, including glass flakes, talc, and nanoclays. In blown LDPE film, the addition of 10% mica was found to reduce the oxygen permeabihty from 4.16 to 3.03 Barrer [37]. Assuming an impermeable, fully oriented lamellar filler, Eq. (8.1), [38] maybe used to predict the composite permeability. Pc, perpendicularly to the filler plane as a function of the matrix permeability, P , filler volume fraction, V(, matrix volume fraction, V , and filler aspect ratio a... 

---