Low cross-link density thermally reversible networks were successfully synthesized from jatropha and sunflower oils. The oils were epoxidized and subsequently reacted with furfurylamine to attach furan groups onto the triglycerides, preferably at the epoxide sites rather than at the ester ones. Under the same reaction conditions, the modified jatropha oil retained the triglyceride structure more efficiently than its sunflower-based counterpart, i.e., the ester aminolysis reaction was less relevant for the jatropha oil. These furan-modified oils were then reacted with mixtures of aliphatic and aromatic bismaleimides, viz. 1,12-bismaleimido dodecane and 1,1′-(methylenedi-4,1-phenylene)bismaleimide, resulting in a series of polymers with Tg ranging between 3.6 and 19.8 °C. Changes in the chemical structure and mechanical properties during recurrent thermal cycles suggested that the Diels–Alder and retro-Diels–Alder reactions occurred. However, the reversibility was reduced over the thermal cycles due to several possible causes. There are indications that the maleimide groups were homopolymerized and the Diels–Alder adducts were aromatized, leading to irreversibly cross-linked polymers. Two of the polymers were successfully applied as adhesives without modifications. This result demonstrates one of the potential applications of these polymers.
A novel biobased monomer for the preparation of thermally reversible networks based on the Diels-Alder reaction was synthesized from jatropha oil. The oil was epoxidized and subsequently reacted with furfurylamine to attach furan groups via an epoxide ring opening reaction. However, furfurylamine also reacted with the ester groups of the triglycerides via aminolysis, thus resulting in short-chain molecules that ultimately yielded brittle thermally reversible polymers upon cross-linking via a Diels-Alder reaction. A full-factorial experimental design was used in finding the optimum conditions to minimize ester aminolysis and to maximize the epoxide ring opening reaction as well as the number of furans attached to the modified oil. The optimum conditions were determined experimentally and were found to be 80 °C, 24 h, 1:1 molar ratio, with 50 mol % of LiBr with respect to the modified oil, resulting in 35% of ester conversion, 99% of epoxide conversion, and an average of 1.32 furans/triglyceride. Ultimately, further optimization by a statistical approach led to an average of 2.19 furans per triglyceride, which eventually yielded a flexible network upon cross-linking via a Diels-Alder reaction instead of the brittle one obtained when the furan-functionalization reaction was not optimized.
The study of rice husk charcoal utilization as gasification waste water treatment Our laboratory works showed that activated char with a specific surface area of 145 m2/g and adsorption capacity of 1.35 mg/g could be prepared by activating rice husk char using 0.5 M of NaOH solution, at 92 oC (boiling point at atmospheric pressure) for 3 hours. Using this simple process, a cheap activated char could be produced, so that the cost of wastewater treatment might be reduced. Base on common rice mill capacity of 6 tonnes/day in north part of West Java, a production of activated char with a daily capacity of 480 kg might be expected. With assumptions of a plant life time of 8 years, an activated char price is IDR 5,000/kg, and an investment of IDR 545 millions, a production unit of activated char based on rice husk was found to be economically attractive with estimated Net Present Value of IDR 1.22 billions and Return on Investment of 27%. Keywords: Rice Husk, Activated Char, Wastewater, Phenol Adsorption, Economic Feasibility AbstrakAdsorpsi dengan arang aktif merupakan salah satu cara pengolahan air limbah yang mengandung senyawa-senyawa turunan fenol. Pemanfaatan sekam padi diharapkan dapat menghasilkan arang aktif yang murah, sehingga penggunaannya dapat mengurangi biaya operasi di dalam pengolahan air limbah industri. Prosedur pembuatan arang aktif sederhana telah dikembangkan di laboratorium, yaitu aktivasi arang sekam padi dengan larutan NaOH 0,5 M, pada titik didih atmosferik dan selama 3 jam. Arang aktif yang diperoleh memiliki luas permukaan spesifik 145 m2/g dan kapasitas adsorpsi fenol sekitar 1,35 mg/g dari air limbah gasifikasi yang mengandung fenol antara 39-44 mg/L. Laju adsorpsi fenol sesuai dengan persamaan pseudo-orde 1 Lagergren, sehingga diduga proses adsorpsi yang dominan dalam percobaan ini adalah adsorpsi fisik. Atas dasar hasil percobaan ini, sebuah unit usaha kecil/menengah diusulkan untuk dikembangkan bersamaan dengan unit penggilingan gabah yang banyak terdapat di pantai utara Jawa Barat. Unit produksi ini dirancang untuk menghasilkan arang aktif dengan kapasitas 480 kg/hari atas dasar kapasitas penggilingan gabah 30 ton/hari. Dengan asumsi umur pabrik 8 tahun, harga arang sekam aktif sebesar Rp 5.000/kg, investasi sebesar Rp 545 juta menghasilkan NPV sebesar Rp 1,22 miliar dan ROI sebesar 27%. Kata Kunci: Sekam Padi, Arang Aktif, Air Limbah, Adsorpsi Fenol, Kelayakan Ekonomi
Triglycerides and fatty acids in palm oil and their derivatives can be utilized as bio-based monomers for synthesizing polymers.
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