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All Journal Jurnal Pengolahan Hasil Perikanan Indonesia Jurnal Sains Materi Indonesia Majalah Kulit, Karet, dan Plastik Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil Jurnal Rekayasa Material, Manufaktur & Energi Indonesian Journal of Chemistry Piston: Journal of Technical Engineering Specta Journal of Technology Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil ASEAN Journal of Chemical Engineering Warta Perkaretan Journal of Materials Exploration and Findings (JMEF) Makara Journal of Technology Journal of Sciencce Technology and Visual Culture Jurnal Sains Materi Indonesia

Mochamad Chalid

Departemen Teknik Metalurgi Dan Material, Universitas Indonesia

Author-ID : 2702950

Aerospace Engineering Agriculture, Biological Sciences & Forestry Arts Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Environmental Science Immunology & microbiology Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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Perilaku Kristalisasi Polipropilena dengan Penambahan Selulosa Mikrofibril Serat Sorgum sebagai Bio-Based Nucleating Agent Ismail, Ika; Chalid, Mochamad
SPECTA Journal of Technology Vol 1 No 1 (2017): SPECTA Journal of Technology
Publisher : LPPM ITK

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35718/specta.v1i1.74

Polypropylene with added Microfibrill Cellulosa as additive materials and filler has been investigated. Polypropylene and sorghum fibre has different interface properties, as the result that the compatibility between both are not good. Therefore, modification process for sorghum fibre is needed, the modification process for sorghum surface are alkalinization and bleaching treatment. Alkalinization process is doing with soaking the sorghum fibre in NaOH solution 2% during 2 hours. Bleaching Process used buffer and NaClO2 during 4 hours. Then, polypropylene and microfibrill cellulose mixed with hot melt mixing method. Characterization for this research is how effect from cellulose in sorghum on crystallization of PP. From DSC analysis showed PP with added microfibrill cellulose 1%wt can increase crystallization temperatures up to 126,510C and crstallization time until 8,26 minutes. And the crystallization process may be accelerated 10 seconds.

Utilization of Recycled PP-Talc Waste into Composite Products with the Hot Melt Mixing Method Muhammad Ariya Afif; Muhammad Nicko Azharry Setyabudi; Mochamad Chalid; Bambang Priyono
Piston: Journal of Technical Engineering Vol 5, No 2 (2022)
Publisher : Prodi Teknik Mesin

Polypropylene (PP) is one type of plastic material often used. As the materials' specifications get higher, PP is combined with other materials to achieve the desired characteristics. One of them is Talc. Behind its significant growth, there is one main problem, namely the mismanagement of plastic waste that causes environmental pollution. Therefore, one method that can overcome this problem is the recycling method. This research was conducted to investigate the characterization between pure and recycled materials and the optimum composition obtained to get finished goods that were close to materials using pure materials. This research was conducted using PP-Talc scrap with 20% and 30% talc content, then combined with dry and hot melt mixing methods. The alloy material was then tested using a Scanning Electronic Microscope (SEM), Universal Testing Machine (UTM), and Simultaneous Thermal Analyzer (STA). The results showed that the recycled material's morphological changes, mechanical properties, and thermal properties almost resembled the pure material. Specific ratios of 20% and 30% recycled PP-Talc gave rise to new morphological changes and mechanical properties.

Perbandingan Sifat Kekerasan dan Penyusutan Produk Berbahan Dasar Polipropilene Murni dan Campuran Hasil Pemanasan Berulang Singgih Prabowo; Mochamad Chalid; Dasep Rusmana
Piston: Journal of Technical Engineering Vol 5, No 2 (2022)
Publisher : Prodi Teknik Mesin

Bahan baku polipropilena (PP) memiliki cakupan luas dalam hal produk yang bisa dihasilkan, mulai dari alat-alat rumah tangga hingga industri. PP yang memiliki keunggulan dapat dibentuk ulang memberikan potensi pemakaian ulang bahan baku yang telah melalui proses pemanasan. Penelitian mengenai perbandingan sifat kekerasan dan penyusutan terhadap produk PP murni dan campuran PP yang telah mendapat pemanasan berulang sebanyak enam kali di dilakukan untuk melihat potensi penggunaannya. Hasil penelitian menunjukkan penurunan sifat kekerasan dan peningkatan penyusutan terjadi seiring penambahan komposisi PP hasil pemanasan ulang. Kekerasan PP 100% murni dibandingkan dengan PP 100% pemanasan ulang ke enam turun sebesar 5% yaitu dari 60,4 Shore D dan 57,4 Shore D. Penyusutan produk masih dibawah 2% baik arah panjang maupun arah lebar. Penyusutan pada arah panjang lebih besar dibandingkan arah lebar, pada produk PP murni terjadi penyusutan sebesar 1,43% pada arah panjang dan 1,35% arah lebar, sedangkan pada produk PP 100% pemanasan ulang arah panjang mecapai 1,65% dan arah lebar 1,61%. Penurunan ini menunjukan bahwa material PP yang telah melalui pemanasan berulang mengalami degradasi walaupun tidak signifikan. Perubahan sifat mekanik (kekerasan) dan fisik (penyusutan) ini sebagai pertimbangan dalam pemilihan bahan dasar murni atau campuran agar mendapatkan produk sesuai dengan spesifikasi dengan memanfaatkan bahan dari sisa produk yang tidak terpakai.

PENGARUH JENIS KARET ALAM TERHADAP SIFAT FISIKA VULKANISAT KARET UNTUK PRODUK BANTALAN JEMBATA Asron Ferdian Falaah; Adi Cifriadi; Mochamad Chalid
Jurnal Sains Materi Indonesia Vol 17, No 2: JANUARI 2016
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

PENGARUH JENIS KARET ALAM TERHADAP SIFAT FISIKA VULKANISAT KARET UNTUK PRODUK BANTALAN JEMBATAN.Vulkanisat karet bantalan jembatan diproduksi melalui beberapa tahapan meliputi pemilihan bahan baku karet, perancangan formulasi kompon, pencampuran, dan vulkanisasi. Pemilihan karet alamuntuk vulkanisat bantalan jembatan merupakan tahapan penting karena mempengaruhi sifat produk akhir. Penelitian bertujuan menganalisis pengaruh penggunaan beberapa jenis karet alam seperti sit asap, karet kompo, karet sit rakyat dan karet standar Indonesia terhadap sifat fisika vulkanisat karet untuk produk bantalan jembatan. Penelitian ini melakukan uji sifat teknis bahan baku karet yang digunakan meliputi uji plastisitas awal (P0); indek ketahanan plastis (PRI); kadar abu; kadar zat menguap; kadar kotoran dan melakukan perancangan kompon karet dan pengujian sifat fisika vulkanisat berupa uji kekerasan; kuat tarik; perpanjangan putus; pengusangan; pampatan tetap; ketahanan ozon yang mengacu pada SNI3967:2013 untuk bantalan jembatan. Hasil penelitian menunjukkan karet sit asap mempunyai sifat teknis yang lebih baik dibandingkan dengan jenis karet mentah lain berdasarkan nilai PRI, kadar abu dan kadar kotoran. Hasil uji sifat fisika untuk parameter kekerasan, kuat tarik, dan perpanjangan putus tidak berbeda nyata, namun setelah pengusangan menunjukkan perbedaan nyata pada nilai kuat tarik dan perpanjangan putus.

Seleksi resin dan rubber processing oil (RPO) dalam pembuatan cushion gum sebagai perekat ban vulkanisir Santi Puspitasari; Norma Arisanti Kinasih; Adi Cifriadi; Arief Ramadhan; Zahra Krishna Hadi; Novita Putri Wahyuni; Mochamad Chalid
Majalah Kulit, Karet, dan Plastik Vol 36, No 1 (2020): Majalah Kulit, Karet, dan Plastik
Publisher : Center for Leather, Rubber, and Plastic Ministry of Industry, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20543/mkkp.v36i1.6105

Cushion gum merupakan salah satu material penting dalam industri ban vulkanisir. Cushion gum berfungsi sebagai perekat yang digunakan pada ban vulkanisir untuk melekatkan bagian karet casing ban lama dengan karet telapak yang baru. Kualitas cushion gum tergantung pada komposisi bahan penyusunnya yang utamanya terdiri dari polimer, resin tackifier, dan plasticizer Rubber Processing Oil (RPO). Riset ini dimaksudkan untuk mempelajari kualitas cushion gum yang dibuat dengan memformulasikan berbagai jenis dan dosis resin tackifier serta plasticizer RPO. Resin (R1-R3) yang digunakan terdiri dari resin coumarone, resorsinol, dan resin turunan hidrokarbon pada dosis 5 phr. Sementara jenis plasticizer RPO (P1-P3) yang dipelajari dalam riset meliputi minyak parafin, minyak pine tar, dan minyak aromatik pada dosis 20 phr. Variasi dosis RPO hanya dibatasi untuk jenis minyak pine tar, yaitu pada 12 dan 20 phr. Pembuatan kompon dilakukan dalam mesin giling terbuka skala laboratorium. Selanjutnya kompon cushion gum dicetak dalam mesin cetak hidrolik pada suhu 150 °C dan tekanan 100 kg/cm2. Vulkanisat cushion gum kemudian diuji sifat mekanis dan kekuatan rekat. Hasil pengujian dievaluasi dan digunakan sebagai dasar dalam menentukan jenis dan dosis resin tackifier dan plasticizer RPO yang terbaik dalam pembuatan cushion gum. Hasil eksperimen menunjukkan bahwa variasi jenis dan dosis resin tackifier dan plasticizer RPO berpengaruh terhadap karakteristik pematangan kompon, sifat mekanis dan kekuatan rekat vulkanisat cushion gum. Formula karet cushion gum paling optimum diperoleh dari perpaduan resin tackifier jenis coumarone sebesar 5 phr dan plasticizer RPO jenis minyak pine tar sebesar 20 phr.

Concentration, distribution, and characteristics of microplastic in estuary, coast and marine organisms in Indonesia: A Preliminary Review Nurhana Rafika Sari; Azizah Intan Pangesty; Mochamad Chalid; Oman Zuas
Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil Vol 6, No 1 (2022)
Publisher : Sekolah Tinggi Ilmu Pertanian Wuna

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29239/j.akuatikisle.6.1.57-64

There is a rising concern regarding the accumulation of microplastics (MPs) in the aquatic ecosystems. Monitoring effort is crucial to understand the concentration and distribution of MPs. The objective of this paper is to mapping the concentration and characteristics of MPs distributed/deposited in estuary, coast, sediment, and marine organism in Indonesia based on data published from the last five years. In the estuary and coast, the highest MPs concentration were located in Brantas River, East Java, around 133 - 5467 particles/m3. In sediment, the highly amount of MP’s, 1136 particles/kg, were found in Kawal village, Bintan Island, Riau. In marine organism, horn snail (Telescopium telescopium) from Rambut Island, Jakarta Bay contained the highest amount of MP’s around 764.81 particles/individual . MPs were commonly found in fragments, fibers, and films with size ranging between 1 μm - 5 mm. Those MPs are mostly made of polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyesters (PES). The data summary obtained in this study could be useful for understanding the sources of MPs as well as monitoring the environmental condition in the aquatic ecosystems.

Structure and Compatibility Study of Modified Polyurethane/Fe3O4 Nanocomposite for Shape Memory Materials Dick Ferieno Firdaus; Masrudin Masrudin; Dessy Ayu Lestari; Mutya Rahmah Arbi; Mochamad Chalid
Indonesian Journal of Chemistry Vol 15, No 2 (2015)
Publisher : Universitas Gadjah Mada

Shape Memory Polymer (SMP) is one of smart materials class that has the ability to recall a given shape before deformation in the transient state. The development of SMP is dominated by polyurethane which is currently focused on the optimization of manufacturing-related research (ease of processing), and the extraction of the potential for biomedical applications. In this study, Shape Memory Polyurethane (SMPU) with Polyethylene Glycol-based material (PEG mw: 6000) as soft segment, 4,4'-Methylenebis (Cyclohexyl isocyanate) (HMDI) as a hard segment and 1,1,1-Trimethylol propane (TMP) as a chain extender were used as a candidate for Vascular Stents. Materials used for the fillers were nano particles of magnetite (Fe3O4) which have 20–50 nm diameters. Variations of the composition were used as a variable. Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) were conducted to investigate the polymer chains which were formed during polymerization, Field Emission Scanning Electron Microscopy (FE-SEM) was used to analyze the interface between the filler and the composite matrix. Manual physical actuation was conducted to analyze the physical recovery and transition temperature of the SMPU. Composition and fillers effect on the performance of SMPU composite were discussed in detail along with analysis of its structure and molecular design.

Synthesis and Characterization of Lignin-Based Polyurethane as a Potential Compatibilizer Salma Ilmiati; Jana Hafiza; Jaka Fajar Fatriansyah; Elvi Kustiyah; Mochamad Chalid
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

Lignin is one of the most abundant biopolymer on earth. It has polar and non-polar side due to its hyperbranched structure, but the polarity of lignin has a higher tendency than non-polarity. Lignin has potential to be compatibilizer if the portion of non-polar can be increased. This research is focused on investigate the synthesis of lignin-based polyurethane to enhance the portion of non-polarity in lignin. Lignin-based polyurethane was prepared by reacting variation 4,4'-Methylenebis(cyclohexyl isocyanate) (HMDI) and polyethylene glycol (PEG), then lignin was added to the reaction. In this study, the structure of lignin-based polyurethane was confirmed by NMR and FTIR. NMR and FTIR showed that lignin successfully grafted. NMR, also used to investigate the variation molar mass of PEG and isocyanate contents effects to polarity of lignin-based polyurethane. The polarity of lignin-based polyurethane decrease as the composition of HMDI and molecular weight of PEG increase. This result also occurs on the sessile drop test that used to determine surface tension of lignin-based polyurethane. The thermal properties of lignin-based polyurethane also investigate using STA. Based on STA, enhancement of composition of HMDI and PEG increase thermal degradation and resistance of lignin-based polyurethane.

Influence of Chemical Treatments Sequence on Morphology and Crystallinity of Sorghum Fibers Ismojo Ismojo; Abdul Aziz Ammar; Ghiska Ramahdita; Anne Zulfia; Mochamad Chalid
Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

Micro-fibrillated cellulose (MFC) derived from natural fibre is continuously gaining interest to produce an environmentally-friendly material, due to economic and ecological reasons. In consequence, sorghum is one of the most-cultivated crops that usually remain the waste as by product of bioethanol production. Indeed, it will be a promising area to utilize sorghum waste to produce MFC for enhancing polymer performance, especially in terms of crystallinity. The objective of this study is to investigate the effect of a sequence of chemical modification was applied to sorghum fibres, i.e. alkalization using 4% sodium hydroxide followed by bleaching using 1.7% sodium chlorite plus acetic acid as a buffer. The treatment was purposed to unbundle the lignocellulose networks into microfibrils cellulose with less amorphous part and lower hydrophilic properties. Evaluation of the chemical treatments effect on internal microstructure, crystallinity index and chemical composition of sorghum fibre was measured via Field-Emission Scanning Electron microscope (FE-SEM), X-ray Diffraction (XRD) and Fourier Transformation Infra-Red (FTIR) Spectroscopy. The experiments show that treatments led to a removal of binding materials, such as amorphous parts hemicellulose and lignin, from the sorghum fibres, resulting MFC of sorghum fibres and enhanced crystallinity index from 41.12 % to 75.73%.

Simulation of Melt Viscosity Effect on the Rate of Solidification in Polymer Jaka Fajar Fatriansyah; Hanindito Haidar Satrio; Muhammad Joshua Yuriansyah Barmaki; Arbi Irsyad Fikri; Mochamad Chalid
Indonesian Journal of Chemistry Vol 19, No 2 (2019)
Publisher : Universitas Gadjah Mada

Phase field model has been successfully derived from ordinary metal phase field equation to simulate the behavior of semi-crystalline polymer solidification phenomenon. To obtain the polymer phase field model, a non-conserved phase field equation can be expanded to include the unique polymer parameters, which do not exist in metals, for example, polymer melt viscosity and diffusion coefficient. In order to expand this model, we include free energy density and non-local free energy density based on Harrowel-Oxtoby and Ginzburg-Landau theorem for polymers. The expansion principle for a higher order of binary phase field parameter was employed to obtain fully modified phase field equation. To optimize the final properties of the products, the solidification phenomenon in polymers is very important. Here, we use our modified equation to investigate the effect of melt viscosity on the rate of solidification by employing ordinary differential equation numerical methods. It was found that the rate of solidification is related to the melting temperature and the kinetic coefficient.

Co-Authors Abdul Aziz Ammar Achmad Nandang Roziafanto Achmad Nandang Roziafanto, Achmad Nandang Adam Febriyanto Nugraha Adi Cifriadi Adi Cifriadi Adi Cifriadi Adiwar Adiwar Adiwar Adiwar, Adiwar Adream Bais Junior Ahmad Z. Taning Anne Zulfia Arbi Irsyad Fikri Arief Ramadhan Arief Ramadhan Arisanti, Anisa Galuh Asron Ferdian Falaah Asron Ferdian Falaah Ausias, Gilles Azizah Intan Pangesty Azizah Intan Pangesty Bambang Priyono Chandra Liza Dasep Rusmana Dedi Priadi Dedi Supriadi Dessy Ayu Lestari Dick Ferieno Firdaus Dimas Agung Setiaji dody andi winarto Elfrida Ratnawati Elvi Kustiyah Elvi Kustiyah Farhan Aziz Fatriansyah, Jaka Fajar Fransiska, Dina Ghazidin, Hafisd Ghiska Ramahdita Ghiska Ramahdita Hanindito Haidar Satrio Hari Eko Irianto Hastiana, Sabina Herry Purnomo Imam Prabowo Imam Prabowo Ismail, Ika Ismojo Ismojo Jana Hafiza Joddy Arya Laksmono Karuana, Feri kristaura, Belle Luh Putu Ratna Sundari Majid Amrullah Masrudin Masrudin Maurice Efroza Mochamad Irfan Fathurrohman Mohamad Irfan Fathurrohman Muhamad Hananuputra Setianto Muhammad Ariya Afif Muhammad Joshua Yuriansyah Barmaki Muhammad Nicko Azharry Setyabudi Mutya Rahmah Arbi Nelson Saksono Nono Darsono Nono Darsono, Nono Norma Arisanti Kinasih Novita Putri Wahyuni Nugraha Wahyu Pratama Nurhana Rafika Sari Nurhayati Nurhayati Oman Zuas Rifathin, Annisa Rini Riastuti, Rini Salma Ilmiati Santi Puspitasari Santi Puspitasari Shinta Dewi Ariantika Sholihah, Maharani Dewi Sianturi, Krisma Yessi Sidartha, B. Boy Rahardjo Singgih Prabowo Solly Aryza Tomy Abuzairi Wijaya, Ade Mundari Wimada, Andrias Rahman Yermia Andri Prawira Zahra Krishna Hadi

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