Sains Malaysiana 46(9)(2017): 1379–1384

http://dx.doi.org/10.17576/jsm-2017-4609-04

Effect of Low Molecular Weight Natural Rubber on Mixing and Vulcanized Properties of Low Energy Processing Natural Rubber

(Kesan Berat Molekul Rendah Getah Asli ke atas Pencampuran dan Sifat Tervulkan Pemprosesan Tenaga Rendah Getah Asli)

SAENGCHAO THONGSEENUCH^1*, WIRACH TAWEEPREDA¹ & KRISDA SUCHIVA²

¹Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University Hat-Yai, Songkhla, 90112 Thailand

²Center for Rubber Research and Technology, Faculty of Science, Mahidol University

Salaya, Nakhonpathom, 73170, Thailand

Diserahkan: 31 Ogos 2016/Diterima: 17 Januari 2017

ABSTRACT

Compounding of natural rubber (NR) requires high energy due to the high viscosity characteristic of NR. In order to reduce the viscosity, low molecular weight of NR (LNR) latex was prepared from field latex by using oxidative phenyl hydrazine/O2 system. LNR latex was mixed with high ammonium NR latex at 3, 5 and 10 phr to provide low energy processing NR (LEPNR). Viscosity molecular weights (Mv) of obtained LNR were 42.59, 18.42 and 6.66 kg/mol, respectively. It was found that the maximum Mooney viscosities and ML 1+4@100°C of LEPNRs were significantly decreased with a decrease of Mv of LNR and an increase of LNR content as well. Specific mixing energy consumptions for mastication step and carbon black incorporation step in Brabender Plasticorder were characterized. The results showed that the mixing energy consumption decreased with an increase of LNR content and a decrease of Mv of LNR. Furthermore, an addition of LNR lowered the viscosity of the compounded rubber, slightly shortened the scorch time, and significantly changed the cure time. Although LNR dropped 50% and 100% modulus of vulcanized rubber, it slightly affected the tensile strength of the vulcanized rubber.

Keywords: Low molecular weight NR; natural rubber; provide low energy processing NR

ABSTRAK

Pengkompaunan getah asli (NR) memerlukan tenaga yang tinggi kerana ciri kelikatan tinggi getah asli. Dalam usaha untuk mengurangkan kelikatan, berat molekul rendah getah asli (LNR) getah diperbuat daripada lateks ladang dengan menggunakan sistem oksidatif fenil hidrazin/O2. LNR getah bercampur dengan ammonium tinggi getah asli getah pada 3, 5 dan 10 phr untuk menyediakan NR pemprosesan tenaga yang rendah (LEPNR). Kelikatan berat molekul (Mv) yang diperoleh LNR masing-masing adalah 42.59, 18.42 dan 6.66 kg/mol. Didapati kelikatan maksimum Mooney dan ML 1+4@100°C LEPNRs telah menurun dengan ketara dengan penurunan sebanyak Mv daripada LNR dan peningkatan kandungan LNR juga. Tenaga penggunaan percampuran tertentu untuk langkah pengunyahan dan karbon hitam disebatikan dalam Brabender Plasticorder telah dicirikan. Keputusan kandungan LNR dan penurunan Mv daripada LNR. Tambahan pula, penambahan LNR menurunkan kelikatan getah kompaun, memendekkan masa pembakaran dan dengan ketara mengubah masa memvulkan. Walaupun LNR menurunkan modulus sebanyak 50% dan 100% getah tervulkan, ia memberi sedikit kesan pada kekuatan tegangan getah tervulkan.

Kata kunci: Getah asli; berat molekul yang rendah NR; memberikan pemprosesan getah asli tenaga yang rendah

RUJUKAN

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*Pengarang untuk surat-menyurat; email: saengchao.t@psu.ac.th