HYDROPHOBIZED LIMESTONE AS FILLER IN POLYMER MATERIALS

Abstract

The article shows changes in certain mechanical properties of polyvinyl chloride (PVC) depending on the quality of added limestone as a filler. Natural limestone and limestone hydrophobicized with stearic acid were added. Modification experiments were carried out with “wet” and “dry” processes in order to find out the required amount of stearic acid for a complete surface coating of limestone - degree of coating 99.90%. Coating of the limestone surface was achieved in the “wet” process with 1.5% stearic acid, while in the “dry” process the same degree of coating was achieved with 3% stearic acid. A significant amount of both “wet” and “dry” modified limestone was prepared.Such product was added to PVC mixture in order to investigate mechanical properties of the obtained PVC product. Research into the mechanical properties of PVC has shown that PVC containing limestone modified by the “wet” process exhibits better mechanical properties than that containing limestone modified by the “dry” process. For example, PVC obtained from a mixture containing limestone modified by the “wet” process with 1.5% stearic acid shows a better tensile strength of 54.20 MPa, while limestone modified by the “dry” process with 3% stearic acid shows a tensile strength 53.20 MPa.