Utilization of volcanic amorphous aluminosilicate rocks (perlite) as alternative materials in lightweight composites

Expanded perlite is worldwide used material. Due to its low bulk density is used mainly in building materials technology as a filler in lightweight composites, thermal, acoustic, fire insulation as well as in horticulture and agriculture. Due to its extremely low bulk density waste expanded perlite is difficult to handle, utilize and causes dust formation. Paper presents method of utilization of volcanic rock as perlite in two structures (raw or expanded) as a valuable, high performance filler to produce a polymer composites material. The composites were prepared by twin-screw extrusion combined with compression molding at a concentration between 0 and 20 wt %. The effect of reinforcement content and ratio of each particle was studied via morphological (SEM), mechanical (tension), rheological (shear) and thermal (DSC) properties The properties were evaluated in both solid and melt state to determine the mechanical performance of these materials. The results show that better dispersion, distribution and interfacial adhesion of the raw perlite in the PP matrix was achieved compared to the expanded perlite. In general, the mechanical properties and thermal stability of PP were improved with perlite addition. For example, the Young's modulus of raw perlite reinforced composites increased by up to 41% (at 15 wt %) compared to the neat PP.