Tinjauan karakteristik foam plastik mikroseluler polistirena dengan penambahan aditif pada teknologi superkritis

Abstract

Processing technology of microcellular plastic represents development of foaming conventional plastic process. The processing of microcellular plastic has been acknowledged as eco-friendly technology because this plastic is produced by the use of benign supercritical carbon dioxide gas as blowing agent. In this work, the samples polystyrene and additive were saturated with supercritical CO₂ at various saturation pressures from 10-22 MPa (at around glass transition temperature of 95 ^oC and 80 ^oC) When the saturation time was accomplished, the solution was decompressed rapidly into atmospheric pressure. The samples were placed in the vessel heated and completed by flowing of carbon dioxide as cooler gas into the vessel. The samples were characterized to observe volume expansion ratio, cell density, average cell diameter and surface fractured with Scanning Electron Microscopy. The microcellular foam of plastic product of PS system has cell diameter between 3.970-9.933 μm , cell density between 9.14x10⁴ – 6.24x10⁹ cell/ cm³. PS-CaCO₃ system has cell diameter between 3.501-8.050 μm, cell density between 3.31x10⁷ – 1.10x10¹¹ cell/cm³, while PS-coconut fiber system hascell diameter between 2.520-8.414 μm, cell density between 1.50x10⁸ -1.60x10¹⁰ cell/cm³ at various pressure.

Keywords: polystyrene, microcellular foam plastic, supercritical CO₂, CaCO₃additive, coconut fiber additive.

Abstrak

Proses pembuatan plastik mikroseluler merupakan pengembangan dari proses pembuatan foam plastik konvensional. Plastik mikroseluler menggunakan fluida superkritis seperti CO₂ dan N₂ sebagai blowing agent yang ramah terhadap lingkungan, sehingga proses pembuatan foam plastik mikroseluler dikenal sebagai teknologi ramah lingkungan. Penelitian ini menggunakan sampel polistirena yang dicampur dengan partikel kalsium karbonat atau sabut kelapa dengan konsentrasi 5% yang diproses pada kondisi tekanan 10-22 MPa (T = 95 ^oC dan 80 ^oC). Setelah kondisi yang diinginkan tercapai dilakukan dekompresi secara mendadak menuju tekanan atmosfer, dan dilanjutkan dengan proses pemanasan, diakhiri dengan mengalirkan gas CO₂ sebagai pendingin. Selanjutnya sampel dikarakterisasi untuk mengetahui rasio volume ekspansi foam, densitas sel, diameter rata-rata sel dan struktur foam yang dihasilkan dengan Scanning Electron Microscope. Pada penelitian ini didapatkan pada sistem PS Murni menghasilkan diameter sel antara 3,970-9,933 μm dan densitas sel 9,14x10⁴ - 6,24x10⁹ cell/cm³. Sistem PS-CaCO₃ menghasilkan diameter sel antara 3,501-8,050 μm dan densitas sel 3,31x10⁷ - 1,10x10¹¹ cell/cm³, dan pada sistem PS-Sabut kelapa menghasilkan diameter sel antara 2,520-8,414 μm dan densitas sel 1,50x10⁸ - 1,60x10¹⁰ cell/cm³ pada berbagai variasi tekanan.

Kata kunci : polistirena, foam plastik mikroseluler, CO₂ superkritis, aditif CaCO_3, aditif sabut kelapa.