Polypropylene perlite-filled

Akin-Okten et al. [21] studied the effect of up to 1000 kGy gamma radiation on the mechanical properties of perlite-filled polypropylene containing up to 50% perlite. 

It was found that the ultimate tensile strength, elongation, and impact strength of the composites all decreased with increasing gamma irradiation. Yet these 

The percentage elongation at break values showed a decreasing trend with the irradiation dose and with the filler content. Perlite addition to nonirradiated polypropylene caused a sharp drop in elongation at break, from nearly 8% elongation for unfilled polypropylene to 2.5% at 50% perlite addition. However, in irradiated polypropylene, the dose of irradiation for a given perlite content was not very large, especially at the 50% perlite level. 

The addition of perlite into virgin unfilled polypropylene reduced the impact strength from 20 kN/m (0.6 J) to a value less than 5 KN/m (0.15 J). The impact strength of unirradiated nnfllled polypropylene also showed a very fast decrease, but it remained almost unchanged with the absorbed ganuna radiation dose, with the exception of the 25 kGy dose. 

The effect of gamma radiation dose on melting temperature TJ for polypropylene containing between 0% and 50% perlite was studied. The melting temperature of the unfilled polypropylene decreases with dose of radiation. This decrease becomes even higher by the addition of perlite into gamma-irradiated polypropylene compared to the unfilled polypropylene with nonirradiated polypropylene, where the addition of perlite increased melting temperatures from 165°C to 172°C. 

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In general, the tensile strength was found to be improved with perlite addition at higher radiation doses, especially for 15% and 30% perlite compositions. The ultimate elongation also decreased with addition of perlite and the radiation dose, but not as fast as observed in nnfllled polypropylene, especially when 50% perlite composites are considered. The impact strength, as can be expected, decreased with perlite addition for nonirradiated polypropylene composites, but it was found that gamma irradiation for both unfilled polypropylene and filled polypropylene did not much alter the impact strength. 

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