PENGARUH WAKTU REAKSI PADA SINTESIS POLYDIMETHYLSILOXANE (PDMS) MENGGUNAKAN TEKNIK RING OPENING POLYMERIZATION TERHADAP KESTABILAN SIFAT MATERIAL - Ajrina Nur Shabrina, - (2021)
Polydimethylsiloxane (PDMS) merupakan cairan pengganti vitreous humour pada operasi vitreoretinal untuk penyembuhan ablasio retina yang keberadaannya dibutuhkan di Indonesia. Polydimethylsiloxane (PDMS) memiliki sifat inert, transparan, dan diketahui memiliki stabilitas yang tinggi. Sintesis sampel PDMS dengan scale-up berhasil dilakukan melalui teknik sintesis ring opening polymerization. Proses sintesis didukung oleh octamethycyclotetralsiloxane (D4) sebagai monomer dan hexamethyldisiloxane (MM) sebagai terminator. KOH dengan konsentrasi sebesar 0,75 M pada proses sintesis digunakan sebagai inisiator. Waktu sintesis untuk PDMS yaitu 35 menit dan 20 menit masing-masing untuk PDMS-1 dan PDMS-2. Sedangkan suhu reaksi adalah 150 ℃. PDMS yang dihasilkan dari proses sintesis bersifat bening, kental, dan tidak berbau yang menandakan bahwa proses sintesis berhasil dan sisa kloroform sudah hilang. Untuk menentukan stabilitas sifat fisis PDMS, pada penelitian ini uji stabilitas pada PDMS hasil sintesis dilakukan selama satu bulan di ruang penyimpanan pada suhu ruang. Sifat fisis PDMS yang meliputi gugus fungsi, viskositas, tegangan permukaan, indeks bias, dan transmitansi diperiksa setiap minggu dalam kurun waktu satu bulan. Hasil uji stabilitas viskositas dan tegangan permukaan menunjukkan bahwa nilai viskositas dan tegangan permukaan PDMS-2 memiliki kestabilan yang lebih baik. Uji stabilitas sifat optik yang meliputi indeks bias dan transmitansi menunjukkan bahwa PDMS-1 dan PDMS-2 mengalami penurunan. Hasil FTIR seluruh sampel PDMS menunjukkan PDMS memiliki gugus fungsi yang sama seperti PDMS komersial setelah penyimpanan selama satu bulan. Secara keseluruhan, viskositas, tegangan permukaan, dan gugus fungsi PDMS-2 relatif lebih stabil dari PDMS-1. Sedangkan sifat optik PDMS terutama transmitansi belum menunjukkan nilai yang stabil karena transmitansi PDMS terus menurun selama masa penyimpanan. Secara keseluruhan, PDMS-2 dengan waktu reaksi 20 menit memiliki nilai kestabilan lebih baik dari PDMS-1 dengan waktu reaksi 35 menit. Polydimethylsiloxane (PDMS) is a replacement for vitreous humor in vitreoretinal surgery for retinal detachment treatment which is needed in Indonesia. Polydimethylsiloxane (PDMS) is inert, transparent, and is known to have high stability. The synthesis of PDMS samples with scale-up was successfully carried out through the ring opening polymerization synthesis technique. The synthesis process was supported by octamethycyclotetralsiloxane (D4) as the monomer and hexamethyldisiloxane (MM) as the terminator. KOH with a concentration of 0.75 M in the synthesis process was used as an initiator. The synthesis time for PDMS was 35 minutes and 20 minutes for PDMS-1 and PDMS-2, respectively. While the reaction temperature is 150 ℃. PDMS produced from the synthesis process is clear, viscous, and odorless which indicates that the synthesis process was successful and the remaining chloroform has disappeared. To determine the stability of the physical properties of PDMS, in this study the stability test on the synthesized PDMS was carried out for one month in a storage room at room temperature. The physical properties of PDMS which include functional groups, viscosity, surface tension, refractive index, and transmittance are checked every week for one month. The results of the viscosity and surface tension stability test showed that the viscosity and surface tension values of PDMS-2 had better stability. Stability test of optical properties which include refractive index and transmittance showed that PDMS-1 and PDMS-2 decreased. The FTIR results of all PDMS samples showed that PDMS had the same functional groups as commercial PDMS after one month of storage. Overall, the viscosity, surface tension, and functional groups of PDMS-2 are relatively more stable than PDMS-1. While the optical properties of PDMS, especially transmittance, have not shown a stable value because the transmittance of PDMS continues to decrease during the storage period. Overall, PDMS-2 with a reaction time of 20 minutes has a better stability value than PDMS-1 with a reaction time of 35 minutes.