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Abstrak :
Oxidation resistance and thermal stability of natural rubber (NR) can be improved by diimide transfer hydrogenation in the latex phase. In this research, non-catalytic diimide transfer hydrogenation of concentrated NR latex was accomplished at various proportions of hydrazine hydrate/hydrogen peroxide. The system was stabilized with the addition of sodium hydroxide. Hydrogenated natural rubber (HNR) was characterized by Fourier Transform Infra Red analysis and degree of hydrogenation. The possibility of side reactions during hydrogenation was also studied by analyzing the gel content and particle size distribution of HNR. It is known that the highest degree of hydrogenation is obtained from the addition of 2 phr hydrazine hydrate and 3 phr hydrogen peroxide at 70oC for a 5-hour diimide transfer hydrogenation of concentrated natural rubber latex, preserved with 1 phr of sodium hydroxide. The higher concentration of hydrogen peroxide trigger crosslink reaction of non-rubber constituent, and depolymerization of HNR molecular chains, were shown by the increased gel content and reduction of HNR particle size distribution, respectively.

Abstrak :
Rubber plasticizer is used to improve rubber processability so as to shorten time and reduce energy consumption during compounding. In general, rubber plasticizer is nonrenewable and environmentally harmful petroleum derivatives due to the carcinogenic property. Environmentally friendly plasticizer can be produced by transfer hydrogenation of vegetable oil. The research was aimed to synthesize new rubber plasticizer from transfer hydrogenation of castor oil using diimide compound which was generated in situ by oxidation of hydrazine hydrate and hydrogen peroxide as well as the application of the new rubber plasticizer obtained on natural and synthetic rubbers compounding. The result showed that the optimum condition of transfer hydrogenation was achieved at a capacity of 1000 ml oil/batch, 40oC for 5 hours, and ratio hydrazine hydrate to hydrogen peroxide at 1:2 due to the hydrogenated castor oil (HCO) had the highest degree of hydrogenation and neutral pH. The application of 10 phr HCO had significant effect on the compounding of EPDM 6250 which was shown by shortest time and lowest energy of compounding, and also by the highest minimum torque modulus. In addition, the crosslink density of rubber vulcanizate which was formed during accelerated sulfur vulcanization was affected both by the addition of HCO and the saturation of the rubber being used.

Bahan pelunak kompon karet berfungsi meningkatkan kemampuan proses karet sehingga dapat mempersingkat waktu dan menurunkan konsumsi energi selama pengomponan. Bahan pelunak karet yang umum digunakan berasal dari turunan minyak bumi yang tidak terbarukan dan tidak ramah lingkungan karena bersifat karsinogenik. Bahan pelunak kompon karet yang ramah lingkungan dapat diproduksi melalui reaksi transfer hidrogenasi minyak nabati. Penelitian ini bertujuan mempelajari sintesis bahan pelunak karet dari minyak jarak kastor secara transfer hidrogenasi menggunakan senyawa diimida yang dibangkitkan secara in situ oleh hidrasina hidrat dan hidrogen peroksida serta aplikasinya dalam pembuatan kompon karet alam (SIR 20) maupun sintetik (EPDM 6250, EPDM 6470, dan Butil 301). Hasil penelitian menunjukkan bahwa kondisi reaksi terbaik dicapai pada kapasitas reaksi sebesar 1000 ml minyak/batch, suhu 40oC selama 5 jam dan rasio penambahan hidrasina hidrat terhadap hidrogen peroksida sebesar 1:2 karena menghasilkan derajat hidrogenasi tertinggi dan memiliki pH netral. Aplikasinya sebagai bahan pelunak alami sebesar 10 bsk berpengaruh signifikan terhadap proses pengomponan karet sintetik tipe EPDM 6250 karena saling memiliki kompatibilitas yang tinggi sehingga mampu memberikan waktu dan energi pengomponan serta nilai torsi minimum terendah. Derajat ikatan silang pada vulkanisat karet yang terbentuk saat vulkanisasi sulfur selain dipengaruhi oleh bahan pelunak juga oleh tingkat kejenuhan karet tersebut.