Hasil Pencarian  ::  Simpan CSV :: Kembali

"EPDM (Ethylene propylene diene monomer) is one of synthetic rubber that widely used in automotive. It must be vulcanized and added by other materials before used. The aim of this study is to investigate the effect of vulcanization system and the addition of carbon black (CB) to the mechanical properties and swelling characteristic of EPDM.This research used three vulcanization system: conventional vulcanization (CV), efficient vulcanization (EV), and semi-efficient vulcanization (SEV) with the variation of carbon black 50, 60, and 70 phr (per hundred resin).This research showed that EV system resulted faster vulcanization time and lower delta torque than SEV and CV systems. This system also performed the highest tensile strength, elongation, and tear strength, while SEV system resulted the highest hardness. Furthermore, the conventional vulcanization system resulted the lowest swelling index."

"Karet alam merupakan salah satu komoditas terbesar yang ada di Indonesia. Kondisi tersebut mendorong perkembangan pesat industri karet. Namun rendahnya modulus kekakuan karet alam menjadi kelemahan dari produk karet alam contohnya ban kendaraan dimana akan menghasilkan sifat yang buruk sehingga berpengaruh kepada umur pakai ban tersebut. Untuk mengkompensasi modulus kekakuannya yang rendah, biasaya karet alam ditambahkan penguat yaitu silica atau carbon black. Tetapi kedua bahan tersebut memiliki kelemahan dimana harganya yang mahal. Alternatif yang dapat digunakan adalah dengan menggunakan penguat berupa serat sorgum. Permasalah kompatibilitas antara karet alam dan sorgum yang memiliki sifat permukaan berbeda menjadi hambatan dalam modifikasi ini. Permasalahan kompatibiltas tersebut dapat diatasi dengan penggunaan coupling agent yang dibuat dari hibrida lateks-pati. Coupling agent merupakan senyawa yang digunakan untuk meningkatkan adhesivitas antara dua material yang berbeda. Pengamatan terhadap perilaku alir vulkaniasi dan kompatibilitas karet alam berpenguat serat sorgum dengan penambahan coupling agent berbasis pati dilakukan untuk dapat mengamati kinetika vulkanisasi. Hasil perilaku alir menunjukkan kenaikan torsi maksimum (MH) dan torsi minimum (ML) serta penurunan waktu pematangan optimum (t90) dan waktu scorch (ts2) dengan adanya penambahan coupling agent berbasis pati. Didapat pula optimasi vulkanisasi pada komposisi coupling agent sebesar 3 phr dan temperatur 150oC. Penambahan coupling agent berbasi pati juga berpengaruh kepada kenaikan nilai laju reaksi dan penurunan energi aktivasi dalam proses vulkanisasi. Hasil karakterisasi menunjukan penambahan coupling agent meningkatkan absorpsi ikatan hidrogen O-H serta menurunkan fiber pull-out dan meningkatkan dispersi yang mengindikasikan kompatibilitas karet alam dengan sorgum meningkat.

---

Natural rubber is one of the largest commodities in Indonesia. This condition encouraged the rapid development of the rubber industry. However, the low modulus of natural rubber has become a weakness of natural rubber products, for example vehicle tires which will produce bad properties which affect the life of the tire. To compensate for the low modulus of stiffness, reinforcement is usually used, which are silica or carbon black. But both of these materials have weaknesses where the price is expensive. The alternative is to use sorghum fiber as a reinforced.

Problems of compatibility between natural rubber and sorghum which have different surface properties are obstacles in binding. The compatibility problems can be overcome by using a coupling agent made from a hybrid of latex-starch. Coupling agent is a compound used to increase adhesivity between two different materials. Observations on the behavior of vulcanization and compatibility of natural rubber reinforced with sorghum fibers with the addition of starch-based coupling agents were carried out to be able to observe vulcanization kinetics.

The results of the flow behavior show the increase in maximum torque (MH) and minimum torque (ML) and decrease in optimum ripening time (t90) and scorch time (ts2) with the addition of starch-based coupling agents. Optimization of vulcanization was also obtained on the composition of coupling agent by 3 phr and temperature of 150oC. Addition of starch-based coupling agent also influences the increase in reaction rate and decrease in activation energy in the vulcanization process.

The characterization results show that the addition of coupling agents increases the absorption of O-H hydrogen bonds and decreases fiber pull-out and increases the dispersion which indicates the compatibility of natural rubber with sorghum increases."

"The land area and production of rubber on smallholder rubber plantations contribute to about 85% and 81% of national rubber production, respectively. Based on this, having technology to utilize vulcanized natural rubber latex (NRL) in a way that is simple, inexpensive, energy-saving, environmentally friendly, and according to the quality standards of the processing of NRL is important. The purpose of the current research is to design of a prototype photoreactor ultraviolet light-emitting diodes (UV-LEDs) for the vulcanization of NRL that is irradiated (VNRLI) to produce NRL-irradiated free carcinogens and protein allergens. The methodology used is the technological development of a prototype photoreactor with an UV-mercury irradiator that located in a vertical cylindrical glass column with the capacity of VNRLI about 249.2 tons/year. The development of technologies applied to increase the capacity of VNRLI by enlarging the area of thin NRL films to be irradiated with UV-A rays derived from UV-LED irradiators that are more energy-efficient, long-life, and environmentally friendly than UV-mercury irradiators. The results allowed for the design of a prototype photoreactor UV-LEDs to process feed NRL with the capacity VNRLI about 522 tons/year. The UV-LED photoreactor prototype design results show that the UV-LED photoreactor prototype is ready to test the VNRLI process function that can produce NRL- irradiated free carcinogen and protein allergens."