الفهرس 
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Abstract
Over 70% of the total production of thermoplastics is accounted by the large volume, low cost commodity resins: polyethylene (PE) of different densities, isotactic polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). Common thermosetting resins are unsaturated polyesters, phenolic resins, amino resins, urea/formaldehyde resins, polyurethanes, epoxy resins, and silicones. Less common thermosets employed in specialized applications are polybismaleimides, polyimides, and polybenzimidazoles. Thermosetting resins are usually low viscosity liquids or low molecular weight solids that are formulated with suitable additives known as cross-linking agents to induce curing, and with fillers or fibrous reinforcements to enhance properties as well as thermal and dimensional stability. Polypropylene (PP) is a thermoplastic polymer and its linear structure based on the monomer CnH2i,with (n) being about 2000.
Additives such as fillers, plasticizers, colorants, etc are applied to all commercially produced Polypropylene resins to protect the polymer during processing and to enhance the end-use performance.(3)
The thermoplastic fillers are of different physical properties mainly the grain size (5- 30 microns), whiteness grade, surface treatment,...etc. for a simple processing and to secure homogenous mixing with the thermoplast used and to avoid damaging of the screw, barrel and the mould, this powder mineral must be first compounded with a thermoplast carrier such as polyethylene or polypropylene. This is an industrial step, where fillers are to be converted into granules by mixing the powder with the carries in a good mixing and blending extrudates in different percentage of 50 up to 90 percent. The fillers are characterized by the type of mineral, its quality (size, whiteness, brightness, purity) and the concentration percentage of the filler in the carrier, in addition to the matrix or carrier used, usually polypropylene or polyethylene. A 60 % calcium carbonate in polyethylene filler means its concentration of 60% and 40% polyethylene carriers.
This type of filler is then added to thermoplastic raw material used in different percentages according to the amount of mineral percentage requested in the final product. This percentage is affecting to a great extent the physical, mechanical, and optical properties of the final product. Huge quantities of calcium carbonate fillers are imnortedtnRovntthat