Mineral fillers characterization

Fillers in composite materials, such as wood fiber and (if any) mineral fillers, are natural friction enhancers, though, strictly speaking, they typically increase abrasion, not friction. It is not important, though, for this consideration is aimed at safety, and it is not an academic discussion about differences between molecular interactions and abrasiveness. As it was described above, neat HDPE is characterized by a low value of coefficients of friction, and the higher the density (specific gravity), the lower the static coefficient of friction. For HDPE density between 0.915 and... 

Abstract Biopolymers are expected to be an alternative for conventional plastics due to the limited resources and soaring petroleum price which will restrict the use of petroleum based plastics in the near future. PLA has attracted the attention of polymer scientist recently as a potential biopolymer to substitute the conventional petroleum based plastics. The chapter aims to highlight on the recent developments in preparation and characterization of PLA blends (biodegradable and non-biodegradable blends), PLA composites (natural fiber and mineral fillers) and PLA nanocomposites (PLA/montmorillonite, PLA/carbon nanotubes and PLA/cellulose nano whiskers). 

Rothon, R.N. (1999) Mineral fillers in thermoplastics filler manufacture and characterization, in Advances in Polymer Science, vol. 139, Springer-Verlag, Berlin, Heidelberg, pp. 67-107. 

Vulcanization kinetic was studied. Mechanical properties of cured composites before and after various regimes of ceramization were investigated. Ceramic phase obtained after heat treatment was characterized by porosimetry and scanning electron microscopy. Morphology and mechanical properties of composites before and after ceramization depend on the type of mineral filler applied, whereas the kinetic of vulcanization is different only for composite containing surface modified montmorillonite. 

The characteristics which determine the properties filler that will impart to a composite are particle shape, particle size, surface area, and particle-matrix compatibility (Fig. 1). Particle-matrix compatibility relates to the ability of the polymer to coat and adhere to the filler. The shape of most mineral filler particles can be a sphere, cube, block, plate, needle, or fiber whereas some filler also contain a mixture of shapes. Mineral particles resembling plates, needles, and fibers are further characterized by their aspect ratio (http //www.rtvanderbilt.com/ fillersintroweb.pdf). In rubber/polymer composites, applied stress is transferred from the rubber/polymer matrix to the strong and stiff mineral. It seems reasonable that this stress transfer will be better affected if the mineral particles are smaller, because greater surface is thereby exposed for a given mineral concentration. Moreover, if these particles have a high aspect ratio (are needle-like, fibrous or platy in shape), they will better intercept the stress propagation through the matrix (Fig. 2) (http //www.rtvanderbilt.com/fillersintroweb.pdf). 

Organic Filler - Organic fillers are made from natural or synthetic organic materials. Natural material derived organic fillers include wood and shell flours. Synthetic material derived fillers include fluoropolymer spheres and milled polymer waste. Organic fillers are characterized by relatively low cost and low density. They might increase the flammability and decrease the moisture resistance of plastics. See also Mineral Filler. 

Plueddemann E P, Silane Coupling Agents, New York, Plenum Press, 1982. Fekete E, Pukansrity B, Toth A. and Bertoti I, Surface modification and characterization of particulate mineral fillers , J Colloid InterfSci 1990 135 200-8. Nakatsuka T, Kawasaki H and Itadani K, Phosphate coupling agents for calcium carbonate filler , J Appl Polym Sci 1982 27 259-69. 

Simple dry-coating trials on mineral substrates afford a way of checking the ability of silicones to become attached to polar sur ces (see Sample preparation and analytical methods above). Calcium carbonate is so important here because it is the most commonly employed filler in facade-coating systems. The organosilicon compounds employed were a monomer (MTMO), a partially characterized MTMO oligomer, and the high polymer H-siloxane used in special commercial fillers for fire-fighting (Table 2). 

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