Effect of KOH concentration on characteristics of polydimethylsiloxane synthesized by ring opening polymerization method

Abstract

Polydimethylsiloxane (PDMS) that widely known as silicone oil is commonly used as vitreous humour substitutes in vitreoretinal surgery. PDMS is needed to be produced in Indonesia and should be provided with sufficient quantity and quality for domestic needs. We synthesized PDMS using ring-opening polymerization method from octamethylcyclotetra-siloxane as monomer, hexamethyldisiloxane as chain terminator, and KOH as catalyst. KOH concentrations are varied from 0.5 M to 2.5 M to study the effect of KOH concentration on characteristics of PDMS. PDMS We successfully synthesized PDMS with a yield in between 39.73% and 65.30% and various viscosities in the range between 0.58 Pa.s and 9.36 Pa.s. From FTIR spectroscopy, it is found that all synthesized samples have structure and functional groups similiar with that of commercial PDMS. From UV-Vis and refractometer measurements, all samples have transparency almost 100% and refractive indexes in the range of 1.3989 to 1.4039. The effect of KOH concentration on the synthesized PDMS gel is on its viscosity, the higher concentration of KOH, the higher viscosity of the obtained PDMS.