Current Density Performances in Poly Ether Ether Keton Membrane for Direct Methanol Fuel Cells

The objective of this study focuses on the characterization of poly ether ether ketone (PEEK) membranes for direct methanol fuel cells (DMFC) application. The PEEK membrane was modified with sulfonation in NMP solvent. The characterized of membrane were done using Scanning Electron Microscopy (SEM), water uptake, methanol permeability, proton conductivity and DMFC test. DMFC tests were performed at room temperature to obtain polarization curves that show voltages and power density of each variable. The results showed that the sulfonation of PEEK method of the polymer increases water uptake. However, the methanol permeability and proton conductivity of membrane decreses. In terms of morphology, it was found that sulfonation of PEEK method can be applied for membrane modification for DMFC application. In terms of the DMFC tests of the membranes, SPEEK proved to have the best performance in stability because of its low methanol permeability

Pengaruh Variasi Komposisi Bahan Pengisi Carbon Black dan Silika pada Sifat Viskoelastis Kompon Karet untuk Tread Ban

Sifat reologi dan viskoelastis pada kompon karet, terutama kompon tread ban, sangat dipengaruhi oleh jenis karet serta bahan pengisi yang digunakan. Kedua sifat ini sangat mempengaruhi hasil akhir dari produk karet terutama dalam hal sifat mekanisnya. Dalam pengembangan suatu produk, penelitian mengenai kedua sifat ini sangatlah penting untuk memperoleh formulasi yang optimum. Penelitian ini bertujuan untuk mengetahui sifat reologi dan viskoelastis dari kompon tread ban menggunakan bahan dasar karet alam (NR) dan butadiene rubber (BR) dengan memvariasikan komposisi bahan pengisi yaitu carbon black dan silika. Bahan dasar NR dan BR dengan rasio 85/15 phr dicampur dengan menggunakan alat kneader, sementara rasio bahan pengisi carbon black/silika adalah: 50/0, 40/10, 25/25, 10/40, dan 0/50 phr. Sifat reologi dan viskositas diuji dengan menggunakan rubber process analyzer (RPA) TA Instrument Elite dan dynamic mechanical analyzer (DMA) 7100 Hitachi. Pengujian RPA dilakukan dengan menggunakan variasi frekuensi dari 0.01-50 Hz pada suhu 1000C dengan amplitudo tetap 10 dan variasi amplitude dari 0,05-3,59 pada suhu 900C dengan frekuensi tetap 1 Hz. Sedangkan pengujian viskoelastis dengan DMA dilakukan menggunakan metode tension-compression dengan rentang suhu pengujian pada -800 – 800C. Hasil uji RPA menunjukkan penambahan silika mempengaruhi interaksi antar bahan pengisi yang ditunjukkan dengan perbedaan pada efek Payne. Energi disipasi juga menunjukkan kecenderungan menurunkan heat build up, meningkatkan sifat mekanis dan memperbaiki ketahanan abrasi pada produk karet dengan tambahan silika sebagai bahan pengisi. Hal ini juga didukung oleh hasil uji DMA yang menunjukkan wet skid resistance pada penggunaan silika yang sebanding dengan penggunaan carbon black saja dan rolling resistance yang meningkat signifikan dengan penambahan silika

Effect of Tackifier Addition on Cushion Compound Formulation for Tire Retreading Application

Tire retreading is a prospective industry. Old tires are repaired and retreaded with suitable tread compounds to fulfill the requirement as the new ones. One of the important components in tire retreading process is cushion compound. Cushion compound consists of unsaturated rubber, in this case natural rubber Hevea Brasiliensis was used, less phr of filler compared to the retread compound, and additives such as peptizer, tackifier, processing oil, antioxidant, activator, accelerator and curatives. Tackifier is an important component in cushion compound since its role to make a bonding between different layer, the initial tire after buffing and new retread layer. Tackifier should has good resistance, good compatibility and does not affect the rheological and dynamical properties of bonded rubber. The general tackifier that used in industries are hexamethyl tetramine as methylene donor and resorcinol as methylene acceptor. There is certain reaction between those two additives that determine how good the performance of cushion compound and its effect to retreading process. To obtain optimum reaction, comparison between resorcinol and hexamethyl tetramine were varied as 1:1 (FRR1), 1:2 (FRR2) and 1:3 (FRR3). Hardness test, compression test, rebound resilience, tensile and tear strength, and FTIR were done to observe the optimum variation for retread application. Compared to the control with no tackifier at all, FRR2 showed the optimum result with 21.75 MPa (min. 19 Mpa) and 454,54% elongation at break (min. 450%). The most interesting result was observation by using FTIR, it was detected that the crosslink density was significantly higher than other formulation. It is a new breakthrough which is minimum tackifier with certain treatment could give better performance