Polypropylene (PP, Homo polymer type, Block copolymer type) and calcium carbonate (CaCO₃) were mixed on a two-roll mill and thin films were prepared by compressing the mixed compound in a hot press.
Mean while, in order to improve the affinity at interface between PP and CaCO₃, various phosphate esters, such as mono alkyl phosphoric ester (MP) of different carbon number were tested as modifiers for CaCO₃. Using deterioration test device, the degradation test was carried out to obtain the measurement of impact strength of PP/CaCO₃ composites.
In the case of Homo polymer type series, the impact strength of PP/CaCO₃ composites increased with the carbon number of MP, in comparison with untreated CaCO₃ filled system, while, untreated system was perfectly degraded at aging temperature 120°C and time100 Hr. In the case of Block copolymer type series, the dependence of impact strength on the carbon number of MP was not clearly recognized, irrespective of aging time. The impact strength of Block copolymer type series (PP/CaCO₃ system) was greater than that of PP one for aging temperature (120°C) and time (100-300 Hr).

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