Sintesis Membran Polistiren dan Polyblend-nya dengan Kitosan untuk Aplikasi Sel Bahan Bakar (Fuel Cell)
SKRIPSI
Mutiara Febryani 10504004
PROGRAM STUDI KIMIA FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM INSTITUT TEKNOLOGI BANDUNG 2008
Sintesis Membran Polistiren dan Polyblend-nya dengan Kitosan untuk Aplikasi Sel Bahan Bakar (Fuel Cell) Synthesis of Polystyrene Membrane and its Polyblend with Chitosan for Fuel Cell Application
SKRIPSI
Mutiara Febryani NIM 10504004
PROGRAM STUDI KIMIA FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM INSTITUT TEKNOLOGI BANDUNG 2008
Abstract Fuel cell is an energy-efficient and environmentally friendly power source that has the answer of the world oil crisis that happen nowadays. Polymer Electrolyte Membrane Fuel Cell (PEMFC) is one of the fuel cell type. PEMFC use polymer electrolyte membrane as a vital component for conducting proton. In this study, polyblend membrane were prepared by blending between polystyrene, sulfonated polystyrene, and chitosan. These membranes are expected to have a good characteristic of proton exchange membrane for PEMFC. Acetyl sulphate is used as polystyrene sulfonating agent. The analysis result showed that after 20 minutes of sulfonation, polystyrene sulfonation level is 25%. Chitosan was synthesized by chitin deacetilation process. The analysis result showed that chitosan deacetylation level is 77%. The polyblend membranes were characterized by Fourier Transform Infra Red (FTIR), Thermal Gravimetry Analysis (TGA), Autograph, and Conductivity Instrument. Swelling experiments and Ion Exchange Capacity (IEC) were evaluated to know the characteristic as an electrolyte membrane. Polyblends of sulfonated polystyren and chitosan were found to posses characteristics as polymer electrolyte membrane.
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Abstrak Semakin berkurangnya cadangan minyak bumi mendorong pencarian sumber energi alternatif yang efisien dan ramah lingkungan, salah satunya adalah sel bahan bakar (fuel cell). Polymer Electrolyte Membrane Fuel Cell (PEMFC) ialah jenis fuel cell yang menggunakan membran polimer elektrolit sebagai komponen pentingnya. Pada penelitian ini disintesis membran polyblend antara polistiren, polistiren tersulfonasi, dengan kitosan yang diharapkan dapat berperan sebagai elektrolit penukar proton pada PEMFC. Proses sulfonasi polistiren dilakukan dengan penambahan asetil sulfat. Proses sulfonasi dengan penambahan gugus sulfonat bertujuan agar polistiren tersulfonasi dapat menghantarkan proton pada PEMFC. Sintesis kitosan dilakukan melalui proses deasetilasi kitin yang telah diisolasi dari kulit udang. Dari hasil analisa diketahui derajat sulfonasi polistiren 25% dan derajat deasetilasi kitosan 77%. Membran polyblend dikarakterisasi melalui Fourier Transform Infra Red (FTIR), swelling, mekanik, termal, konduktivitas, dan Ion Exchange Capacity (IEC). Penambahan polistiren tersulfonasi dan kitosan memberikan pengaruh pada sifat termal dan sifat mekanik polyblend serta nilai IEC dan konduktivitas.
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Program Studi Kimia Fakultas Matematika dan Ilmu Pengetahuan Alam Institut Teknologi Bandung
Menerangkan bahwa Skripsi yang disusun oleh : Nama : Mutiara Febryani NIM
: 10504004
telah disetujui sebagai persyaratan untuk mendapatkan gelar Sarjana Kimia
Bandung,
Juni 2008
Pembimbing
Dr. I Made Arcana NIP. 131801348
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Untuk ibu dan bapak.. Atas segala doa dan kasih sayang yang telah diberikan sampai aku bisa menyelesaikan penulisan skripsi ini :)
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Ucapan Terimakasih Alhamdulillah, segala puji dan syukur kepada Allah SWT atas segala karunia-Nya hingga penulis berhasil menyelesaikan tugas akhir dan penulisan skripsi. Penulis mengucapkan banyak terima kasih kepada semua pihak yang telah membantu : 1. Dr. I Made Arcana selaku dosen pembimbing yang telah banyak membantu, memberi saran, dan membimbing dengan sabar dalam penyelesaian tugas akhir dan skripsi 2. Ibu dan Bapak, atas segala doa, perhatian, kasih sayangnya, dukungan, dan nasehat selama 22 tahun ini 3. Kakak-kakakku; mbak Yul, mas Pri, mas Budi, mba Asti, mas Yoyo, teh Dian, mas Adi, dan mba Ida atas segala doa, bantuan, dukungannya selama ini 4. Ponakan-ponakanku yang lucu-lucu; Brevi, Dinda, Dania, Biyya, dan Paw-paw. Walaupun masih kecil-kecil dan belum ngerti, tapi kehadirannya selalu bikin kangen dan betah di rumah ;) 5. Rahadian Arthapati atas perhatian, dukungan, kesabaran, dan bantuannya selama tiga tahun terakhir. 6. Seluruh staf pengajar Program Studi Kimia ITB, atas ilmu dan pengetahuan yang diberikan selama 4 tahun terakhir 7. Teman seperjuangan dan senior di Lab Kimia Fisik Material ; Lelly, Hana, Herlina, Anti, Erit, Veli, Fahri, Adit, Yuyus, pak Bambang, pak Dani, pak Siang, pak Maskuri, yang telah banyak memberi bantuan, bimbingan, dan kebersamaan selama bekerja di Lab. 8. Teman-teman seangkatan kimia 2004 atas kebersamaannya dan bantuannya selama ini. Ami dan Mega, bikin suasana di kimia lebih menyenangkan. Juga untuk Ria, Daniel, Astri, Yoad, Fendi, atas bantuannya mengajar saat belajar bersama. Temen main dan belajar bareng di kimia; Rona, Mutiw, Hana, Her, Megaw, Putri, Indah, Tina, Ogi 9. Seluruh staf karyawan Program Studi Kimia ITB, terutama Bu Entin, Pak Wahyo, Bu Soni dan Bu Tini, atas segala bantuan yang telah diberikan. 10. Kak empat dan kak Titi atas memberi masukan dan kesediannya menjawab pertanyaan saat penulis sedang merasa kesulitan di Lab. 11. Teman-teman senior dan junior di kimia yang banyak memberikan informasi dan pengalamannya
12. Teman-teman di MBWG, terutama ; Nova, Achie, Wahyu, Rina, Amar, Krisna, Fufu; juga ranger pit ☺ : Dhana, Dwi, Cukie, Made, Asep, Citra. Terima kasih selama ini banyak memberikan pengalaman, pelajaran, dan tempat merefresh saat sedang jenuh. 13. Temen seperjuangan di kost-an Cisitu 97C ; Nona, Fufu, Nissa, dan Denik yang banyak membantu dan mendengarkan keluhan penulis selama ini. 14. Six mates ; Denik, Keeky, Terry, Chintia, Pe-I, atas kebersamaannya sampai sekarang. 15. Semua pihak yang telah membantu dalam penulisan skripsi ini namun tidak dapat disebutkan satu per satu. Terima kasih.
Dengan kehadiran kalian semua, penulisan skripsi ini dapat diselesaikan. Terima kasih banyak atas segala bantuannya. Mohon maaf atas segala kekurangan yang terdapat dalam skripsi ini dan semoga skripsi ini dapat memberi manfaat bagi pembacanya.
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Daftar Isi Abstract.................................................................................................................................... ii Abstrak.................................................................................................................................... iii Ucapan Terimakasih ............................................................................................................... vi Daftar Isi ............................................................................................................................... viii Daftar Tabel ............................................................................................................................ xi Daftar Gambar ....................................................................................................................... xii Daftar Lampiran..................................................................................................................... xv 1 Pendahuluan.......................................................................................................................... 1 1.1 Latar Belakang................................................................................................................. 1 1.2 Tujuan Penelitian ............................................................................................................. 2 1.3 Ruang Lingkup Penelitian ............................................................................................... 2 2 Tinjauan Pustaka................................................................................................................... 4 2.1 Stiren................................................................................................................................ 4 2.2 Polistiren (PS).................................................................................................................. 4 2.3 Polistiren Tersulfonasi (PSS)........................................................................................... 6 2.3.1
Sulfonasi Polistiren ..................................................................................................... 6
2.3.2
Agen Sulfonasi............................................................................................................ 6
2.4 Kitin ................................................................................................................................. 7 2.5 Kitosan............................................................................................................................. 7 2.6 Membran Polyblend ........................................................................................................ 8 2.7 Fuel Cell .......................................................................................................................... 8 2.7.1
Jenis Fuel Cell ............................................................................................................ 9
2.7.2
Bagian-bagian PEMFC ............................................................................................. 10
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2.7.3
Reaksi yang terjadi pada PEMFC............................................................................. 11
2.7.4
Hambatan Fuel Cell .................................................................................................. 12
2.8 Karakterisasi .................................................................................................................. 13 2.8.1
Penentuan Massa Molekul Polimer .......................................................................... 13
2.8.2
Penentuan Derajat Sulfonasi Polimer ....................................................................... 14
2.8.3
Penentuan Derajat Deasetilasi Kitosan ..................................................................... 14
2.8.4
Analisis Gugus Fungsi .............................................................................................. 15
2.8.5
Analisis Termal......................................................................................................... 16
2.8.6
Analisis Mekanik ...................................................................................................... 16
3 Metodologi Penelitian......................................................................................................... 19 3.1 Alat dan Bahan .............................................................................................................. 19 3.1.1
Alat ........................................................................................................................... 19
3.1.2
Bahan ........................................................................................................................ 20
3.2 Cara Kerja...................................................................................................................... 20 3.2.1
Polistiren ................................................................................................................... 23
3.2.2
Polistiren Tersulfonasi (PSS).................................................................................... 24
3.2.3
Kitosan...................................................................................................................... 24
3.2.4
Pembuatan Polyblend ............................................................................................... 25
3.2.5
Karakterisasi ............................................................................................................. 26
4 Hasil dan Pembahasan ........................................................................................................ 29 4.1 Sintesis Polistiren .......................................................................................................... 29 4.2 Sintesis Kitosan ............................................................................................................. 34 4.3 Pembuatan Polyblend .................................................................................................... 37 4.3.1
Analisa gugus fungsi polyblend................................................................................ 39
4.4 Analisis swelling............................................................................................................ 40 4.5 Analisis Mekanik ........................................................................................................... 41
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4.6 Thermal Gravimetry Analysis (TGA) ............................................................................ 42 4.7 Ion Exchange Capacity (IEC) dan konduktivitas .......................................................... 45 5 Kesimpulan dan Saran ........................................................................................................ 47 5.1 Kesimpulan .................................................................................................................... 47 5.2 Saran .............................................................................................................................. 47 Daftar Pustaka........................................................................................................................ 48 Lampiran................................................................................................................................ 50
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Daftar Tabel Tabel 4. 1 Sintesis polistiren ...................................................................................... 30 Tabel 4. 2 Data serapan IR polistiren (PS) dan polistiren tersulfonasi(PSS)............. 34 Tabel 4. 3 Data sintesis kitosan.................................................................................. 35 Tabel 4. 4 analisa IR kitin dan kitosan....................................................................... 36 Tabel 4. 5 Data komposisi polimer penyusun polyblend ........................................... 38 Tabel 4. 6 Hasil kurva IR polyblend 80-10-10 .......................................................... 40 Tabel 4. 7 Data hasil derajat swelling ........................................................................ 41 Tabel 4. 8 Hasil uji mekanik polyblend ..................................................................... 41 Tabel 4. 9 Hasil analisa TGA..................................................................................... 42 Tabel 4. 10 Hasil IEC dan konduktivitas ................................................................... 46 Tabel A. 1 Data sintesis polistiren..........................................................................................50 Tabel A. 2 Data penentuan derajat sulfonasi ......................................................................... 50 Tabel B. 1 Waktu alir asam asetat dan larutan kitosan…………………………………….. 52 Tabel B. 2 Viskositas larutan kitosan .................................................................................... 52 Tabel B. 3 Waktu alir toluen dan larutan polistiren............................................................... 53 Tabel B. 4 Viskositas larutan polistiren................................................................................. 53 Tabel C. 1 Data analis swelling……………………………………………………………..55 Tabel C. 2 Data analisisIEC................................................................................................... 55 Tabel C. 3 Data konduktivitas ............................................................................................... 56 Tabel C. 4 Data analisis mekanik .......................................................................................... 56 Tabel C. 5 Hasil uji tarik........................................................................................................ 57
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Daftar Gambar Gambar 2. 1 Struktur stiren...................................................................................................... 4 Gambar 2. 2 Struktur polistiren ............................................................................................... 5 Gambar 2. 3 Polimerisasi stiren ............................................................................................... 5 Gambar 2. 4 Struktur kitin ....................................................................................................... 7 Gambar 2. 5 Struktur kitosan ................................................................................................... 8 Gambar 2. 6 Mekanisme fuel cell .......................................................................................... 12 Gambar 2. 7 Penentuan derajat deasetilasi kitosan ................................................................ 15 Gambar 3. 1 Diagram alir keseluruhan penelitian ................................................................. 22 Gambar 3. 2 Alat polimerisasi ............................................................................................... 23 Gambar 3. 3 Alat press .......................................................................................................... 26 Gambar 3. 4 Alat FTIR .......................................................................................................... 27 Gambar 3. 5 Autograph ......................................................................................................... 27 Gambar 3. 6 Alat ukur konduktivitas..................................................................................... 28 Gambar 4. 2 Reaksi sintesis polistiren................................................................................... 29 Gambar 4. 3 Polistiren hasil sintesis ...................................................................................... 30 Gambar 4. 4 Reaksi sintesis asetil sulfat (A) dan sulfonasi polistiren (B)............................ 31 Gambar 4. 5 Polistiren tersulfonasi........................................................................................ 31 Gambar 4. 6 Struktur polistiren (A) dan polistiren tersulfonasi (B) ...................................... 32 Gambar 4. 7 Kurva IR polistiren............................................................................................ 33 Gambar 4. 8 Kurva IR polistiren tersulfonasi ........................................................................ 33 Gambar 4. 9 Skema isolasi kitin dan sintesis kitosan ............................................................ 35 Gambar 4. 10 Kitosan hasil sintesis....................................................................................... 35 Gambar 4. 11 Struktur kitin (A) dan kitosan (B) ................................................................... 36 Gambar 4. 12 Kurva IR kitin ................................................................................................. 37 Gambar 4. 13 Kurva IR kitosan ............................................................................................. 37 Gambar 4. 14 Membran polyblend dengan komposisi PS-PSS-Kitosan ............................... 38 Gambar 4. 15 Kurva IR polyblend komposisi 80-10-10........................................................ 39 Gambar 4. 16 Kurva TGA polistiren ..................................................................................... 43 Gambar 4. 17 Kurva TGA polyblend 80-20-0 ....................................................................... 43 Gambar 4. 18 Kurva TGA polyblend 80-10-10 ..................................................................... 44
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Gambar 4. 19 Kurva TGA polyblend 80-0-20 ....................................................................... 44 Gambar B. 1 Kurva phi red terhadap konsetrasi kitosan…………………………………... 52 Gambar B. 2 Kurva phi red terhadap konsentrasi larutan polistiren...................................... 54 Gambar D. 1 Membran dengan komposisi 20% PSS-80% kitosan ………………………...59 Gambar E. 1 Spektrum IR Kitosan………………………………………...……………….61
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Daftar Lampiran Lampiran A Sintesis Polistiren dan Kitosan .......................................................................... 50 Lampiran B Penentuan Massa Molekul Rata-Rata Viskositas (Mv) ..................................... 52 Lampiran C Data dan Perhitungan Analisis Polyblend ......................................................... 55 Lampiran D Percobaan Pembuatan Polyblend ...................................................................... 58 Lampiran E Penentuan Derajat Deasetilasi Kitosan .............................................................. 61
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