Inorganic fillers, whiskers

Thus, inorganic whiskers as fillers have the anisotropy of fibers and could support the skeleton function. In addition, inorganic whiskers could be evenly dispersed in the composite material because of its small size and would not lead to anisotropy. Therefore, polymers filled with inorganic whiskers are more advantageous. 

Comparison between Inorganic Whiskers and Previous Inorganic Fillers... 

Fibrous fillers for biomedical PLA-based FRPs include carbon and inorganic fibres [406], PLLA (i.e. self-reinforcement) [407,408], poly(p-dioxane) fibre [409], chitin [410], biodegradable fibre (e.g. bioactive glass, chitosan fibre, polyester amides) [411], hydroxyapatite fibre [412], hydroxyapatite whiskers [413], halloysite (Al2Si205(0H)4) nanotubes [414] and the fibre from different tissue types of Picea sitchensis [415],... 

Inorganic materials such as chalk, flour, china, clay, mica, barytes. Fuller s earth, Aerosil (finely divided Si02), asbestos, glass-fiber, and metal or oxide single crystals (whiskers) are all used as fillers. Organic fillers include wood flour, cellulose flakes, foam-rubber chips, paper cuttings. 

Sustainability of the materials becomes one of the prime concerns in the research development in industries and academic institutions. The search for nonpetroleum-based fillers has accelerated the research into bio-nanofillers from biomass. In some cases, bio-based nanocomposites show unique advantages over traditional inorganic nanoparticles. Commonly used bio-nanofillers in NR are whiskers of cellulose, chitosan, nanocrystals of starch etc. The studies on these fillers are aimed at competitive production cost and equivalent properties as compared to other petroleum-based fillers. In addition, biocompatibility and biodegradability of the bio-based fillers are hoped to be retained after dispersion in the NR matrix. 

The macroscopic inorganic fibers worsen the processability of the composites, increasing abrasion on the processing equipment surface. A solution to this problem may be the addition of LC Polymer to ease the processability due to the very low melt viscosity of LC Polymer. Moreover, they also provide reinforcement effect at a microscale. These types of composite, in which thermoplastics are reinforced by both organic and inorganic fibers, are called "in-situ hybrid" composites. The fillers, whiskers and fibers are used as inorganic reinforcements for this type of composite. 

The thermal stability of a material sometimes is represented by the temperature of 5% decomposition and usually can be determined by a thermogravimetric method. Because inorganic fillers have a high melting point, adding inorganic fillers into resin can improve the heat resistance of the polymer. A composite material is prepared by filling calcium carbonate whiskers into PP material. The thermal decomposition temperature (5% decomposition) of the composite material increased from 366.7 to 400.6°C as the whisker content was enhanced. 

Hiroshi Urayama, Chenghuan Ma, Yoshiharu Kimura. Mechanical and thermal properties of poly(l-lactide) incorporating various inorganic fillers with particle and whisker shapes. Macromolecular Materials and Eneineerine. 2P,Wy.5h2-56S, 2003. 

Available fillers are of various types and forms, namely, rigid, flexible, spherical, ellipsoidal, flakes, platelets, fibers or whiskers. They may be organic or inorganic in nature. All varieties of fillers have been tried in polymers in order to impart various advantageous benefits. The presence of the fillers in ttie polymer matrix alters the rheological properties of the polymer. 

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