Simetrikal Journal of Engineering and Technology Vol. 01, No. 02, 2019 | 79-86 SIMETRIKAL Journal of Engineering and Technology __________ *Corresponding author at: Department of Chemical Engineering, University of Sumatera Utara, Jl. AlmamaterKampus USU Medan, 20155, Sumatera Utara, Indonesia E-mail address: indradanas@yahoo.com Copyright © 2019 Published by Talenta Publisher, p-ISSN: 2656-1476, e-ISSN: 2655-8599 Journal Homepage: https://talenta.usu.ac.id/index.php/jet Effects of TESPT-Silane Coupling Agent on Torque Properties and Degree of Filler Dispersion of Silica Filled Natural Rubber and Epoxidized Natural Rubbers Compounds Indra Surya 1 , and Nabil Hayeemasae 2 1 Department of Chemical Engineering, Universitas Sumatera Utara, Medan, 20155, Indonesia 2 Department of Rubber Technology and Polymer Science, Faculty of Science and Technology, Prince of Songkla University, Patani Campus, 94000, Pattani, Thailand Abstract. The effect of the addition of a bis(triethoxysilylpropyl) tetra sulphide or TESPT- silane coupling agent on torque properties and degree of filler dispersion of silica-filled compounds of natural rubber (NR), epoxidized natural rubbers with 25% mole of epoxidation (ENR 25) and epoxidized natural rubbers with 50% mole of epoxidation (ENR 50) were investigated. All the rubbers were filled by silica filler at a fixed loading (30.0 parts per hundred rubber, phr) and the TESPT was added to each silica-filled rubbers compounds at 1.0phr. It was found that TESPT affected the torque properties of all the silica-filled rubbers compounds. The TESPT decreased the minimum torque of NR system but increased the minimum torque of ENRs systems and maximum and torque differences of the all rubbers systems. The minimum torque was decreased from 0.61 to 0.53 dN.m for NR; were increased from 0.23 to 0.49 dN.m for ENR 25 and from 0.07 to 0.34 dN.m for ENR 50.It was also found that the TESPT acted as an internal plasticizer for NR which improved the degree of silica dispersion. Presumably, for the ENRs, the TESPT acted as an additional cross linker with a more pronouncedly which poorer the degree of silica dispersion. Keywords: Torque properties, TESPT, Silica, Degree of filler dispersion Abstrak. Pengaruh penambahan suatu bahan bis(triethoxysilylpropyl) tetrasulphide atau bahan penggandeng TESPT terhadap sifat-sifat tork dan derajad penyerakan pengisi dari kompon-kompon terisi silika dari karet alam (KA), karet-karet alam terepoksidasi 25 persen mol (KAT 25) dan 50 persen mol (KAT 50). Kesemua jenis karet tersebut terisi silica dengan kadar 30.0 bagian per seratus bagian karet, bsk) dan TESPT ditambahkan kemasing-masing kompon-kompon karet terisi silica dengan kadar 1.0 bsk. Ditemukan bahwa TESPT berpengaruh kepada sifat-sifat tork dari semua jenis kompon karet terisi silica tersebut. TESPT menurunkan tork minimum dari sistim KA tetapi menaikkan tork minimum sistim-sistim KAT, tork maksimum dan selisih tork dari kesemua sistim karet. Tork minimum turun dari 0.61 ke 0.53 dN.m untuk KA; naik dari 0.23 ke 0.49 dN.m untuk KAT 25 dan dari 0.07 ke 0.34 dN.m untuk KAT 50. Diketemukan juga, TESPT bertindak sebagai bahan pemplastik internal untuk KA yang meningkatkan derajad penyerakan silika. Diasumsikan untuk KAT 25 dan KAT, TESPT bertindak lebih sebagai bahan penyambungsilang tambahan yang menurunkan derajad penyerakan silika.