SINTESIS, KARAKTERISASI, DAN UJI KINERJA HIDROGEL KOMPOSIT POLI(VINIL ALKOHOL)/NATRIUM ALGINAT/BORAKS/KALIUM KLORIDA UNTUK KANDIDAT MATERIAL CONTROLLED RELEASE FERTILIZER - Siti Fatimah, - (2023)
Abstrak: Penelitian ini bertujuan untuk mengetahui komposisi optimum sintesis, karakterisasi dan uji kinerja hidrogel untuk kandidat material control release fertilizer (CRF). Hidrogel disintesis dari poli(vinil alkohol) (PVA) dan natrium alginat (SA) sebagai prekursor, boraks sebagai crosslinker, serta kalium klorida (KCl) sebagai nutrien. Tahapan penelitian meliputi sintesis hidrogel melalui metode solution mixing, optimasi komposisi rasio PVA/SA dan PVA/SA/Boraks, karakterisasi menggunakan instrumentasi spektrofotometer Fourier Transform Infra-Red (FTIR), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) dan sudut kontak, serta uji kinerja meliputi swelling ratio, water retention dan release behavior. Hasil penelitian menunjukkan hidrogel PVA/SA/Boraks/KCl berhasil disintesis melalui metode solution mixing, dengan komposisi swelling optimum 1:1:0.05:1 mL. Hasil karakterisasi hidrogel PVA/SA/Boraks/KCl terjadi pergeseran puncak serapan dan terbentuknya puncak baru pada spektra FTIR untuk vibrasi CH, C=O, -CH stretching, dan B-O, -CO, Cl bending mengindikasikan adanya interaksi kimia antar prekursor. Terdapat permukaan halus merata dari dominan PVA berdasarkan foto SEM. Pergeseran puncak difraksi sekitar 11.56, 19.57, 42.04˚ dan puncak baru 12.78, 17.14, 19.06, 20.37˚ pada spektra XRD menghasilkan perubahan nilai jarak interlayer, ukuran kristalit, dan %kristalinitas menunjukkan adanya peningkatan interaksi ikatan hidrogen antar prekursor. Penurunan nilai sudut kontak dari 36˚ (PVA/SA/Boraks) menjadi 33˚ (PVA/SA/Boraks/KCl) menunjukan sifat super hidrofilik. Penambahan crosslinker dan nutrien memiliki kinerja yang meliputi meningkatkan %swelling ratio dari 634% menjadi 760%, menurunkan water retention dari 11.5 hari menjadi 5 hari, serta perilaku release behaviour hidrogel PVA/SA/Boraks/KCl dengan media air pH 7 dan pH 8.14 memiliki kesamaan perilaku slow release pada pengamatan 30 detik selama 2460 detik (41 menit). Kata kunci: hidrogel, PVA/SA/Boraks/KCl, CRF, sintesis, karakterisasi Abstract: This study aims to determine the optimum synthesis composition, characterization and hydrogel performance test for control release fertilizer (CRF) candidate materials. The hydrogel was synthesized from poly (vinyl alcohol) (PVA) and sodium alginate (SA) as precursors, borax as a crosslinker, and KCl as a nutrient. The stages of the research included the synthesis of hydrogels through the solution mixing method, optimizing the composition ratio of PVA/SA and PVA/SA/Borax, characterization using the instrumentation of the Fourier Transform Infra-Red (FTIR) spectrophotometer, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and contact angle, as well as performance tests including swelling ratio, water retention and release behavior. The results showed that the PVA/SA/Borax/KCl hydrogel was successfully synthesized using the solution mixing method, with an optimum swelling composition of 1:1:0.05:1 mL. The results of the characterization of the PVA/SA/Boraks/KCl hydrogel showed a shift in absorption peaks and the formation of new peaks in the FTIR spectra for CH, C=O, -CH stretching, and B-O, -CO, Cl bending vibrations indicating the presence of chemical interactions between precursors. There is an even smooth surface of the dominant PVA based on SEM photos. Diffraction peak shift around 11.56, 19.57, 42.04˚ and new peaks 12.78, 17.14, 19.06, 20.37˚ in the XRD spectra resulted in changes in the values of interlayer distance, crystallite size, and %crystallinity indicating an increase in the interaction of hydrogen bonds between precursors. Decreasing the value of the contact angle from 36˚ (PVA/SA/Boraks) to 33˚ (PVA/SA/Boraks/KCl) shows super hydrophilic properties. The addition of crosslinkers and nutrients has performance which includes increasing the %swelling ratio from 634% to 760%, reducing water retention from 11.5 days to 5 days, as well as the release behavior of the PVA/SA hydrogel /Borax/KCl with water media pH 7 and pH 8.14 has the same slow release behavior at 30 seconds of observation for 2460 seconds (41 minutes). Keywords: hydrogel, PVA/SA/Borax/KCl, CRF, synthesis, characterization