Thermoplastics and Calcium Carbonates

Worldwide, ready-to-be-processed CaCOg filled polymers are available from a number of compounders. Polypropylene compounds, in the 10-40%wt range are available from numerous producers and grades up to 50%wt are also locally offered for special applications. Table 6.8 gives the average properties of typical commercial PP-CaCOg composites, as compiled from manufacturers data sheets (when available). 

Commercial PP-CaCOj Composites Average Suppliers Data 

Theoretical densities were calculated with respect to the given weight percentage of CaCOj and considering that the filler was coated with fatty acid(s), 10% of its weight the following densities were used PP, 0.90 CaCOs, 2.76 fatty acid(s), 0.88 (average value for lauric, Unoleic, myristic, oleic, palmitic, and stearic acids). 

Mechanical properties of commercial PP-CacOs composites ° are averaged suppliers data the vertical bars indicate the standard deviations shaded diamonds are data from one single manufacturer shaded triangles are data from B. Haworth, C.L. Raymond. Proceedings Eurofillers 97, Manchester, UK, Sept. 8-11,251-254,1997 the curves in the left part have been calculated with the Guth and Gold equation. 

In compiling data used to fill Table 6.8, no attention could be paid to the quality of the calcium carbonate used in preparing the composites and particularly to the presence of a surface modifier, because this information is 

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