Proses Pembuatan Plastik Foam Mikroseluler Dengan Pemanfaatan Irradiasi Ultrasonik

Adam, Fajar Firstya (2020) Proses Pembuatan Plastik Foam Mikroseluler Dengan Pemanfaatan Irradiasi Ultrasonik. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Plastik foam mikroselular merupakan termoplastik foam dengan morfologi sel tertutup, diameter dibawah 50 μm dan densitas sel sekitar 109-1015 sel/cm3. Struktur selular yang terbentuk dapat meningkatkan kekuatan thermal dan mekanis dari material tanpa penambahan bahan baku. Tahapan proses pembuatan plastik foam yaitu penjenuhan polimer dengan blowing agent (CO2 superkritis), dianjutkan pembentukan struktur selular melalui penurunan tekanan & peningkatan suhu pada system polimer/gas, lalu stabilisasi struktur terbentuk. Tahapan pembentukan sel yang melibatkan fenomena nukleasi & pertumbuhan sel menentukan struktur selular yang dihasilkan. Sehingga, laju nukelasi sel dan pertumbuhan dalam proses foaming harus dikendalikan dengan baik. Pada studi ini, akan dilakukan pembuatan plastic foam mikroselular kerapatan sel tinggi melaui metode temperature induced batch foaming dengan pemanasan yang memanfaatkan irradiasi utrasonik secara simultan. Ini dilakukan untuk mempertahankan kondisi super-saturasi dan meningkatkan laju pembentukan sel. Hasil dari metode kemudian dibandingkan dengan metode konvensional yang menggunakan pemanasan saja melalui karakterisasi densitas sel, ukuran sel, morfologi dan rasio ekspansi. Sebagai tambahan, fenomena yang berkaitan akan disimulasikan untuk mendukung pernyataan bahwa laju nukleasi akan meningkat dengan semakin efektifnya proses pemanasan melaui pendekatan transfer panas konduksi 1D yang diintegrasikan dengan persamaan laju nukleasi. Hasilnya foaming dengan irradiasi ultrasonik simultan, rasio ekspansi meningkat 1,52 kali lipat, meningkat seiring dengan suhu pemanasan. Densitas sel lebih tinggi diperoleh dengan penerapan ultrasonik suhu foaming 50oC, namun hanya sedikit perbedaan yang dapat dilihat, yaitu sekitar 1010-1011 sel / cm3. Dari hasil distribusi ukuran sel, sel terdistribusi di sekitar 0,5-3,5 μm, dengan atau tanpa perlakuan ultrasonik untuk 60 dan 70oC. Sementara itu pada suhu foaming 50oC, ukuran sel lebih rendah diperoleh pada kondisi foaming dengan ultrasonik yaitu di kisaran 0,3-2,4 μm, dibandingkan tanpa ultrasonic. Melalui hasil simulasi, proses foaming dengan ultrasonic dapat meningkatkan laju pemanasan dan laju nukleasi akibat penambahan generasi panas kedalam polystyrene, namun energy dari ultrasonic sangat dipengaruhi suhu medium perambatan. Perbedaan nampak pada suhu 40-50oC. Hal ini dipengaruhi oleh pengaruh energy dari kavitasi yang nilainya semakin kecil dengan peningkatan suhu. Meskipun hasil prediksi masih memberikan error SSE sebesar 33 untuk pemanasan tanpa ultrasonic dan 44.6 dengan ultrasonik, namun simulasi cukup memberikan hasil yang representatif. =========================================================================================================================================================================== Microcellular Plastic Foam is a thermoplastic foam which characterized by its cell size and density below 50 μm 109-1015 sel/cm3 respectively. Dispersed gas that trapped inside its matrices which form cellular structure was benefit to strengthen its thermal and mechanical properties without both the addition of any raw materials and losing its main properties. The process stages of making plastic foam are include the saturation of polymer with a blowing agent (supercritical CO2), then cellular structure is formed by perturb the thermodynamic-stable of the system with pressure drop or temperature increment, and finally the cellular structure stabilized by terminate its growth. The cellular formation which related with nucleation and growth of the cell determine the structure obtained. Hence, strictly speaking that both of the nucleation rate and growth should be well controlled. In this study, temperature induced foaming with simultaneously ultrasound irradiation will be carried out to to optimize the heating process in the making of production the high-density microcellular foam. This method is carried out in order to maintain the supersaturation degree, furthermore enhance the nucleation rate. The results upcoming will be compared with the conventional heating method through cell density, cell size, morphology and foam expansion ratio. Additionally, the phenomena related with this technique will be modeled and simulated to justify that the effective heating process, the higher nucleation rate will be, through 1D conductive heat transfer approximation which integrated into nucleation rate equation. The results demonstrate, that foaming under ultrasound, the expansion ratio attained up to 1.52 fold, increased along with the heating temperature. Higher cell densities obtained with ultrasound applied at 50oC, however only slight difference can be seen, which about 1010-1011 cell/cm3. From the cell size distribution results, cell distributed around 0.5-3.5 μm, with or without ultrasound applied for 60 and 70oC, meanwhile at 50oC of foaming, the lowest cell size obtained with the aid of ultrasound in the range of 0.3-2.4 μm. From simulation results, the ultrasonic foaming process is able to increase the heating rate and nucleation rate due to the addition of heat generation into polystyrene, however the energy from ultrasonic is strongly influenced by the temperature of the propagation medium. Discrepancies are shown at a temperature of 40-50oC. This is influenced by the cavitational activity energy, which diminished with increasing the temperature. Even though the prediction results still give an error with SSE 33 for without ultrasound and 44.6 with ultrasound irradiation, the simulation is sufficient to provide representative results.

Item Type: Thesis (Masters)
Uncontrolled Keywords: polystyrene, plastic foam mikroseluler, irradiasi ultrasonik, CO2 superkritis
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK3401 Insulation and insulating materials
T Technology > TP Chemical technology > TP1140 Polymers
T Technology > TS Manufactures > TS170 New products. Product Development
T Technology > TS Manufactures > TS195 Packaging
Divisions: Faculty of Industrial Technology > Chemical Engineering > 24101-(S2) Master Thesis
Depositing User: Fajar Firstya Adam
Date Deposited: 24 Aug 2020 07:45
Last Modified: 27 Aug 2020 09:03
URI: https://repository.its.ac.id/id/eprint/80757

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