Zeta potentials of perlite modified with dimethyldichlorosilane, 3-aminopropyltriethoxysilane and dimethyloctadecylchlorosilane

Abstract

Expanded perlite (EP) samples have been treated with dimethyldichlorosilane (DMDCS), 3-aminopropyl-triethoxy-silane (3-APT) and dimethyloctadecylchlorosilane (DMODCS). By studying the IR spectra of the samples, the perlite surface was found to be modified as a result of its interaction with modifying agents. The electrokinetic properties of the modified perlite samples have been investigated by measuring the zeta potentials. While expanded perlite samples have negatively charged surfaces and have no pH(IEP) in the pH range of 3-11, the perlite sample modified by 3-APT has a pH(IEP) value of about 7.2. DMDCS- and DMODCS-modified perlite surfaces have been found to have negative zeta potentials. The interactions between perlite and DMDCS, 3-APT and DMODCS occurring during the modification have been discussed according to the data obtained.