ZETA POTENTIALS OF PERLITE MODIFIED WITH DIMETHYL-DICHLOROSILANE, 3-AMINOPROPYLTRIETHOXYSILANE AND DIMETHYLOCTADECYLCHLOROSILANE

摘要

Expanded perlits (EP) samples have been treated with dimethyldichlorosilane (DMDCS), 3-aminopropyl-triethoxy-silane (3-APT) and dimethyloctadecylchlorosi-lane (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 elec-trokinetic 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.