Plastics organoclay additives

In the quoted study, it was found that the polysulfone is initially miscible with the cyanate prepolymer and phase separates in spherical microdomains during the course of the cyanate polymerization process. The flexural modulus was not significantly modified by the thermo-plastic/organoclay addition. On the other hand, the fracture toughness was slightly improved with the addition of polysulfone and clay to the cyanate. 

Flame retardants based on phosphorous show certain disadvantages. Some of them have to be included in large amounts in order to achieve the desired grade of flame retardancy, however, undesired side effects then emerge. For example, resorcinol diphosphate plasticizes the composition and significantly reduces the heat deflection temperature of the formulation. Examples for phosphorous-based flame retardants for PPE include resorcinol diphosphate, bisphenol A diphosphate, tetraxylyl piperazine di-phosphoramide, ete. Organoclay additives show synergistic effects with phosphates with respeet to flame retardancy. For this reason, the amount... 

Incarnate and co-workers [2004] reported that at constant clay content the CPNC modulus increases with the extrusion rate. Addition of clay shifted the main E" peak position by about 60 to 70°C. The same authors [2003] also investigated the viscoelastic properties of a PA-6 and its statistical, partially aromatic copolymer, ADS, with 3, 6 and 9wt% C30B. In tensile mode the low-T relative modulus, increased from 1.15 to 1.54 (at 1 Hz and 5°C/min). The influence of clay on Tg might be attributed to the confinement of polymer chains in silicate galleries, which partially hinders the molecular motion [Ash et al., 2002]. It is significant that Tg does not always increase with organoclay content, as the outcome is influenced by the type, quantity, and miscibility of the plasticizing intercalant. 

Polypropylene (PP) is one of the most widely used plastics in large volume. To overcome the disadvantages of PP, such as low toughness and low service temperature, researchers have tried to improve the properties with the addition of nanoparticles that contains p>olar functional groups. An alkylammonium surfactant has been adequate to modify the clay surfaces and promote the formation of nanocomposite structure. Until now, two major methods, i.e., in-situ polymerization( Ma et al., 2001 Pirmavaia, 2000) and melt intercalation ( Manias et al.,2001) have been the techniques to prepare clay/PP nanocomposites. In the former method, the clay is used as a catalyst carrier, propylene monomer intercalates into the interlayer space of the clay and then polymerizes there. The macromolecule chains exfoliate the silicate layers and make them disperse in the polymer matrix evenly. In melt intercalation, PP and organoclay are compounded in the molten state to form nanocomposites. 

In various asphalt processing methods, the rheological properties of the compounded asphalt are of primary importance. One invention shows how, by blending different fractions of crude oil, the processing properties can be optimized for pavement applications. In another recent invention,solvent-free polyurethane was compounded with asphalt. Such products have always contained substantial amounts of solvents to reduce viscosity to the level that allows the material to be cold applied with simple techniques. Using organoclay as compatibilizer for polyurethane and asphalt and a suitable plasticizer, elimination of solvent becomes possible. In addition to environmental safety, these products can be used safely on substrates which would otherwise be affected by solvents the formulation (e.g., polystyrene insulation boards). This is one example which shows that the benefits of solvent free systems go beyond the elimination of air pollutants. 

The decomposition of ammonium compounds, as considered for neat organoclays, may not necessarily be the exact degradation process occurring in a polymer matrix. It may be altered by complex interactions between nanocomposite components and products of their thermal decomposition. The composition of commercial polymeric materials containing dispersed nanoparticles is quite complex, as it incorporates a set of additional additives, such as UV and thermal stabilizers, plasticizers, and dyes and other fillers. These additives may considerably influence the degradation mechanism [38, 39]. 

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