PENGARUH WAKTU PERLAKUAN ALKALI TERHADAP KEKUATAN MEKANIK KOMPOSIT rHDPE-SERAT PELEPAH SALAK
PENGARUH WAKTU PERLAKUAN ALKALI TERHADAP
KEKUATAN MEKANIK KOMPOSIT rHDPE-SERAT
PELEPAH SALAK
SKRIPSI
Ditujukan sebagai salah satu syarat Untuk memperoleh gelar
Sarjana Teknik
SYARIF HIDAYATULLOH
NIM. I0412049
PROGRAM STUDI S1 TEKNIK MESIN
FAKULTAS TEKNIK UNIVERSITAS SEBELAS MARET
SURAKARTA
2018
“Raihlah ilmu, dan untuk meraih ilmu belajarlah untuk tenang dan sabar.” (Umar bin Khattab)
“Barang siapa yang keluar untuk mencari ilmu maka ia berada di jalan Allah “hingga ia pulang.”.
(HR. Turmidzi) “Janganlah memandang kepada siapa yang bicara, tetapi perhatikanlah apa yang ia bicarakan.”
(Ali bin Abi Thalib)
PENGARUH WAKTU PERLAKUAN ALKALI TERHADAP KEKUATAN
MEKANIK KOMPOSIT rHDPE SERAT PELEPAH SALAK
Syarif Hidayatulloh Program Studi Teknik Mesin
Fakultas Teknik, Universitas Sebelas Maret Surakarta, Indonesia
Email: 2syarif2@gmail.com
Abstrak
Penelitian ini bertujuan untuk menyelidiki pengaruh perlakuan alkali terhadap sifat mekanik komposit rHDPE-serat pelepah salak yaitu kekuatan bending dan kekuatan impak. Material komposit yang diteliti terdiri atas serbuk rHDPE sebagai matrik dan serat pelepah salak sebagai penguat. Variasi perlakuan alkali menggunakan NaOH 5% dari 1 hingga 5 jam. Spesimen dicetak dengan metode cetak tekan hot press pada tekanan 48,6 bar, temperatur 150°C dan waktu penahanan 25 menit. Sifat mekanik komposit diketahui dengan melakukan uji bending dan impak berturut-turut menurut ASTM D-790 dan ASTM D-5941.
Hasil penelitian komposit rHDPE-serat pelepah salak menunjukkan kekuatan bending mengalami peningkatan pada perlakuan alkali serat pelepah salak pada perendaman 1, 2, dan 3 jam lalu mengalami penurunan pada 4 dan 5 jam. Kekuatan bending tertinggi dimiliki komposit dengan perlakuan alkali serat pelepah salak 3 jam yaitu sebesar 33,62 MPa sedangkan nilai kekuatan impak komposit menurun karena perlakuan alkali serat, nilai kekuatan impak komposit
2 tertinggi yaitu pada komposit tanpa perlakuan alkali serat sebesar 31,36kJ/m .
Kata kunci: alkali , kekuatan mekanik , komposit, rHDPE, serat pelepah salak
EFFECT OF ALKALI TREATMENT TIME ON MECHANICAL
PROPERTIES OF rHDPE-ZALACCA FIBER COMPOSITE
Syarif Hidayatulloh Mechanical Engineering Department
Engineering Faculty, Sebelas Maret University Surakarta, Indonesia
Email: 2syarif2@gmail.com
Abstract
This research aims to investigate the effect of alkali treatment on themechanical properties of rHDPE - zalacca midrib fibers composite. The
composite material under study consisted of rHDPE powder as a matrix and
zalacca midrib fibers as a reinforcement. Variation of alkali treatment using
NaOH 5% from 1 to 5 hours. The specimens were made by hot pressing method at
48,6 bar pressure, temperature at 150° C and 25 minutes of holding time. The
composite mechanical strength is known by conducting bending test according to
ASTM D790 and impact test according to ASTM D594The results of composite rHDPE- zalacca midrib fibers showed that bending
strength increased in alkaline treatment of zalacca midrib fibers during
immersion of 1, 2, and 3 hours then decreased at 4 and 5 hours. The highest
bending strength of the composite has 3 hours alkaline which is 33.62 MPa while
the composite impact strength value decreases as the alkaline fiber treatment, the
highest composite impact strength value is on the composite without alkali
2 treatment of fiber of 31.36kJ / m .
Keywords: alkaline, mechanical strength, composite, rHDPE, zalacca midrib
fiberDAFTAR ISI
HALAMAN JUDUL ........ ............................................................................................... i HALAMAN SURAT PENUGASAN .............................................................................ii PERNYATAAN INTEGRITAS PENULIS ................................................................. iii HALAMAN PENGESAHAN ........................................................................................ iv HALAMAN DESIMINASI ........................................................................................... v HALAMAN MOTTO ................................................................................................... vi ABSTRAK ....................................................................................................................vii KATA PENGANTAR ................................................................................................... ix DAFTAR ISI ................................................................................................................... x DAFTAR GAMBAR .................................................................................................. xiii DAFTAR TABEL ......................................................................................................... xv DAFTAR RUMUS....................................................................................................... xvi DAFTAR NOTASI .....................................................................................................xvii DAFTAR LAMPIRAN ............................................................................................. xviii
BAB I PENDAHULUAN ....................................................................................... 1
1.1 Latar Belakang Masalah ............................................................................... 1
1.2 Rumusan Masalah ........................................................................................ 3
1.3 Batasan Masalah ........................................................................................... 4
1.4 Tujuan Penelitian .......................................................................................... 4
1.5 Manfaat Penelitian ........................................................................................ 4
1.6 Sistematika Penulisan ................................................................................... 4
BAB II TINJAUAN PUSTAKA DAN DASAR TEORI ........................................ 6
2.1 Tinjauan Pustaka .......................................................................................... 6
2.2 Dasar Teori ................................................................................................... 9
2.2.1 Komposit .............................................................................................. 9
2.2.2 HDPE (High Density Polyethylene) ................................................... 13
2.2.3 Serat Pelepah Salak ............................................................................ 13
2.2.4 Perlakuan Alkali ................................................................................. 14
2.3 Pengujian Spesimen ................................................................................... 15
2.3.1 Densitas Serat ..................................................................................... 15
2.3.2 Pengujian Serat Tunggal ..................................................................... 16
3.6.5 Tahap Analisis .................................................................................... 33
4.2 Hasil Pengujian Komposit Serat Pelepah Salak ...................................... 46
4.1.3 Kekuatan Dan Modulus Tarik Komposit Serat Tunggal .................... 45
4.1.2 Hasil Uji Foto SEM Serat Tunggal ..................................................... 40
4.1.1 Hasil Uji Kandungan Dan Uji Densitas Serat..................................... 39
4.1 Hasil Pengujian Serat .............................................................................. 39
BAB IV HASIL DAN ANALISA ........................................................................ 39
3.9 Jadwal Penelitian ..................................................................................... 36
3.8 Diagram Alir Penelitian........................................................................... 35
3.7.2 Uji Impak ............................................................................................ 35
3.7.2 Uji Bending ......................................................................................... 34
3.7.2 Uji Serat Tunggal ................................................................................ 34
3.7.1 Uji Densitas ........................................................................................ 33
3.7 Bentuk dan Ukuran Spesimen Uji ............................................................. 33
3.6.4 Tahap Pengujian ................................................................................. 33
2.3.3 Pengujian Lentur ................................................................................. 16
3.6.3 Pembuatan Spesimen Komposit ......................................................... 32
3.6.2 Persiapan Serat Pelepah Salak ............................................................ 31
3.6.1 Persiapan rHDPE ................................................................................ 30
3.6 Langkah Kerja Penelitian .......................................................................... 30
3.5 Parameter .................................................................................................... 30
3.4 Alat Uji ....................................................................................................... 27
3.3 Alat Penelitian ............................................................................................ 23
3.2 Bahan Penelitian ......................................................................................... 21
3.1 Tempat Penelitian ....................................................................................... 21
BAB III METODE PENELITIAN........................................................................ 21
2.5 Hipotesis ..................................................................................................... 20
2.4 Variabel Penelitian ..................................................................................... 19
2.3.4 Pengujian Impak Izod ....................................................................... 18
4.2.1 Pengaruh Penambahan Perlakuan Alkali Terhadap Kekuatan Impak ............................................................................................................ 46
4.2.2 Pengaruh Penambahan Perlakuan Alkali Terhadap Kekuatan- Bending .............................................................................................. 48
4.2.2 Pengujian SEM Komposit .................................................................. 51
BAB V KESIMPULAN ........................................................................................ 54
5.1 Kesimpulan ................................................................................................. 54
5.2 Saran ........................................................................................................... 55 DAFTAR PUSTAKA ........................................................................................... 56 LAMPIRAN .......................................................................................................... 59
DAFTAR GAMBAR
Gambar 2.1 Grafik Kekuatan Tarik Serat Tunggal Kenaf- Poliester .................... 6Gambar 2.2 Grafik Modulus Tarik Uji Tarik Serat Tunggal Kenaf- Poliester ..... 7Gambar 2.3 Grafik Kekuatan Impak Komposit Serat Aren-Polyester .................. 7Gambar 2.4 Kekuatan Impak Komposit Serat Rami-Polyester ........................... 8Gambar 2.5 Grafik Kekuatan Bending Komposit Serat Kenaf-Polyester ............. 9Gambar 2.6 Grafik Modulus Bending Komposit Serat Kenaf-Polyester .............. 9Gambar 2.7 Pembagian Komposit ...................................................................... 11Gambar 2.8 Pengujian Densitas ......................................................................... 15Gambar 2.9 Spesimen Uji Tarik Serat Tunggal .................................................. 16Gambar 2.10 Mekanisme Pengujian Three Point Bending ................................... 17Gambar 2.11 Peletakan Spesimen Uji Impak Izod ............................................... 18Gambar 3.1 Plastik RHDPE ................................................................................ 21Gambar 3.2 Pelepah Salak .................................................................................. 22Gambar 3.3 Wax Mirror Glaze ........................................................................... 22Gambar 3.4 Kertas Karton .................................................................................. 22Gambar 3.5 Lem Epoxi ....................................................................................... 23Gambar 3.6 Mesin Hot Press .............................................................................. 23Gambar 3.6 Oven ................................................................................................ 23Gambar 3.8 Mesin Crusher ................................................................................. 24Gambar 3.9 Ayakan ............................................................................................ 25Gambar 3.10 Timbangan Digital........................................................................... 25Gambar 3.11 Blender ............................................................................................ 26Gambar 3.12 Mesin Roll ....................................................................................... 26Gambar 3.13 Gunting ............................................................................................ 26Gambar 3.14 Mesin Tenso .................................................................................... 27Gambar 3.15 Universal Testing Machine ............................................................. 28Gambar 3.16 Mesin Impak Izod............................................................................ 28Gambar 3. 17 Mesin SEM model JOEL tipe JSM-6701F .................................... 29
Gambar 3.18 Kertas lakmus .................................................................................. 29Gambar 3.19 Serbuk HDPE .................................................................................. 31Gambar 3.20 Perendaman Serat ............................................................................ 31Gambar 3.21 Serat Pelepah Salak ......................................................................... 32Gambar 3.22 Spesimen ......................................................................................... 32Gambar 3.23 Spesimen Uji Densitas .................................................................... 34Gambar 3.24 Spesimen Uji Tarik Serat Tunggal .................................................. 34Gambar 3.25 Spesimen Uji Bending ..................................................................... 34Gambar 3.26 Spesimen Uji Impak ........................................................................ 35Gambar 3.27 Diagram Alir Penelitian .................................................................. 35Gambar 4.1 Grafik Uji Kandungan ....................................................................... 40Gambar 4.2 Hasil Uji Foto SEM Serat Tanpa Perlakuan Alkali .......................... 41Gambar 4.3 Hasil Uji Foto SEM Serat Perlakuan Alkali 1 Jam ........................... 41Gambar 4.4 Hasil Uji Foto SEM Serat Perlakuan Alkali 2 Jam ........................... 42Gambar 4.5 Hasil Uji Foto SEM Serat Perlakuan Alkali 3 Jam ........................... 42Gambar 4.6 Hasil Uji Foto SEM Serat Perlakuan Alkal 4 Jam ............................ 43Gambar 4.7 Hasil Uji Foto SEM Serat Perlakuan Alkali 5 Jam ........................... 43Gambar 4.8 Grafik Kekuatan Tarik Serat Tunggal- – Lama Perlakuan Alkali ...... 45
- – Lama Perlakuan Alkali ............................................................................................... 45
- – Lama Perlakuan Alkali .......................... 47
- – Lama Perlakuan Alkali ........................ 48
- – Lama Perlakuan Alkali.......................... 49
DAFTAR TABEL
Tabel 2.1 Karakteristik HDPE .............................................................................. 13Tabel 2.2 Komposisi Kandungan Pelepah Salak .................................................. 14Tabel 3.1 Jadwal Penelitian................................................................................... 31Tabel 4.1 Nilai Densitas Serat ............................................................................... 39
DAFTAR RUMUS
Rumus 2.1 Perlakuan Alkali ................................................................................. 14 Rumus 2.2 Pengujian Densitas .............................................................................. 15 Rumus 2.3 Tegagan Tarik Serat Tunggal ............................................................. 16 Rumus 2.4 Regangan Serat Tunggal ..................................................................... 16 Rumus 2.5 Kekuatan Bending............................................................................... 17 Rumus 2.6 Kekuatan Impak Secara Umum .......................................................... 18 Rumus 2.7 Energi Total Yang Diserap ................................................................. 19 Rumus 2.8 Energi Total Yang Diserap ................................................................. 19 Rumus 2.9 Nilai Kekuatan Impak Benda Uji........................................................ 19 Rumus 4.1 Pengujian Densitas .............................................................................. 40 Rumus 4.2 Pengujian Densitas .............................................................................. 41
= Kekuatan bending (MPa)
b σ
2
= Nilai kekuatan impak (J/m )
o
) = Sudut naik awal lengan ayun ( = Lebar spesimen (m)
o
) = Sudut pantul lengan ayun (
o
) ′ = Sudut pantul lengan ayun tanpa mengenai benda ( = Tebal spesimen (mm) ℎ = Ketebalan benda uji (m) = Panjang penumpu (mm) R = Jarak dari pusat rotasi pendulum ke pusat massa (m) = Beban bending maksimal (N) w = Berat pendulum (N) = Energi total yang diserap (J)