The Effects Different Size of Batu Reput as a Filler in SMR L and ENR- 50 Blends

Transcription

1 The Effects Different Size of Batu Reput as a Filler in and ENR- 50 Blends J. N. M. Ridhwan 1, N. Z. Noriman 1, a, M. A. A. Mohd Salleh 1, and S. Ragunathan 2 and N. Z. Nik Yahya 1 1 School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 2, Arau, Perlis, Malaysia.. 2 School of Enviromental Engineering, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, Arau, Perlis, Malaysia. a niknoriman@unimap.edu.my Keywords: Batu Reput ; Standard Malaysian Rubber (); Epoxidized natural rubber (ENR- 50); Tensile properties; Morphological study Abstract. The effects of different sizes of Batu Reput filler which are S1 (< 63 μm) and S2 (75-150μm) on tensile and morphological properties of Batu Reput filled and epoxidized natural rubber () blends were investigated. Results indicated that, the tensile properties, such as tensile strength (TS), elongation at break (E b ) and stress at 100% elongation (M100) of Batu Reput filled better than Batu Reput filled blends, particularly, at 15 phr of smaller size of Batu Reput. The scanning electron microscopy studies proved, smaller size of Batu Reput in Batu Reput filled illustrated a better Batu Reput - matrix interaction compared with Batu Reput filled blends. Introduction Malaysia is the one of the largest producer of natural rubber (NR) in the world, and wellknown as superior quality and widely used as a benchmark in the global market. Malaysia s NR production accounted for almost 14 per cent of the world s NR in The industry s contribution further improved to reach RM24.2 billion in 2006, representing an increase of RM3.2 billion or 15.2 per cent from 2005 [1]. (Standard Malaysian Rubber) is a grade of Technically Specified Rubber (TSR) which recognized in year 1965 with bales size of 33.3 kg by Standard Malaysian Rubber (SMR) scheme. Based on this specification, has maximum nitrogen levels (0.6% wt), maximum dirt levels (0.03% wt), maximum ash levels (0.5% wt), maximum volatile matters (0.8% wt), minimum Wallace rapid plasticity (Po) (30) and minimum plasticity retention index (PRI) (60%) [2]. Epoxidized natural rubber (ENR) is a promising rubber which has recently attracted the attention of many researchers. ENR was chemically modified form of the cis-1,4- polyisoprene rubber, whereby some of the unsaturation is converted into epoxide groups, which are randomly distributed along the polymer chain [3]. It is gained by chemical modification of natural rubber (NR) by employing performic or peracetic acid [4 7]. As natural rubber is epoxidized, ENR has some special properties such as low gas permeability, excellent oil resistance, and good anti-wet skid resistance, coupled with highly damping properties [8,9]. Perlis state located in Northern region of peninsular Malaysia is one of the major producers of bright-coloured rock called Batu Reput. This mineral can be found around Chuping area in Perlis [10]. Currently, carbon black and silica are dominant as filler. This mineral may become suitable substitute as filler in applications for natural rubber compound because of it has high contents of CaO (76.61%), MgO (14.07%) also C (8.96%) and SiO 2 (0.36%) and it low cost compared to others traditional commercial fillers [8]. To the best of our knowledge, less work has been done dealing with Batu Reput act as filler, particularly blending with rubber. In this study, the effects of Si69 on tensile properties and morphological properties of Batu Reput filled blends were reported.

2 Experimental Materials. The materials used in this study were Standard Malaysian Rubber () and was obtained from RRIM Guthrie Group Sdn. Bhd., whereas a Batu Reput particles, i.e., S1 (less than 63 μm) and S2 ( μm) was purchased from the Government of Perlis, Malaysia. Other compounding ingredients, such as N-cyclohexyl-2-benzothiazole sulfonamide (CBS), zinc oxide, stearic acid and sulphur were all purchased from Anchor Chemical Co. Their description and supplier are illustrated in Table 1. Table 1: List of raw materials, their functions and suppliers Raw Material Description Supplier & Elastomer Batu Reput Filler - S1(< 63 μm) - S2(75-150μm) Zink oxide, Stearic acid, Sulphur, N-cyclohexyl-2- benzothiazole sulfonamide (CBS) Compounding ingredients RRIM Guthrie Group Sdn. Bhd. Government of Perlis. Anchor Chemical Co. (M) Ltd. Preparation of Blends. The Batu Reput filled blends were formulated with blend ratios of 100/5, 100/15, 100/25, 100/35, and 100/50, as given in Table 2. The rubber was preblended and the mixing procedure was carried out in accordance with ASTM D [11] using a two-roll mill at room temperature. Cure characteristics were studied at C using a Monsanto Moving Die Rheometer (MDR 2000) according to ASTM D with about 4 g samples of the respective compound. The rubber compounds then were compression molded at C using a hot press according to respective cure times, t 90. Table 2: Formulation of Batu Reput filled blends Material BR05 BR15 BR25 BR35 BR50 SMRL & Batu Reput ZnO Stearic acid Suphur CBS Measurement of Tensile Properties. Dumbbell shaped test pieces were cut from molded sheets previously conditioned for 24 h at room temperature. A minimum of five specimens were measured for each particular sample (blend) and the average values were reported. Tensile tests were performed using an Instron 5582 machine at a crosshead speed of 500 mm/min according to ASTM D 412. Scanning Electron Microscope (SEM). Testing on morphology of tensile fracture surface of the sample was investigated by using scanning electron microscope (SEM) model JEOL JFC6460LA. Surfaces of the samples were mounted on aluminium stubs and sputter coated with a thin layer of gold about nm thickness prior to avoid electrostatics charging and poor resolution during examination.

3 Results and Discussion Tensile Properties. Table 3 shows the effect of different particle sizes of filler and its blend ratios on tensile properties of Batu Reput filled and Batu Reput filled. Results indicated that, TS, E b and M100, for both and blends, increased up to 15 phr of Batu Reput (optimum loading), then decreased at all over the blends. The increment of both blends up to 15 phr of Batu Reput loading, due to better filler-rubber interaction, shown later in morphology studies. At 15 phr of Batu Reput (optimum loading), a good distribution of Batu Reput filler in both blends contributed to better tensile strength. However, at similar Batu Reput loading, particularly at 15 phr, the S1(< 63 μm) of Batu Reput filled gives higher TS, E b and M100 compared to Batu Reput filled. This was due to the, S1 providing high surface area contact hence gives better dispersions of filler in the rubber matrix. The deterioration of TS, E b and M100 at higher Batu Reput content was due to a weak interaction between Batu Reput and both rubber matrixes. Table 3: The effects of different particle sizes of filler and its blend ratios on tensile properties of Batu Reput filled and Blend/Different sizes of filler Tensile strength Elongation at M100 (MPa) break (%) (MPa) BR05 S S S S BR15 S S S S BR25 S S S S BR35 S S S S BR50 S S S S Morphological Properties. Figure 1 (A, and B) and 2 (A, and B) shows the scanning electron microscopy (SEM) of tensile fracture surface of Batu Reput filled blends and Batu Reput filled blends with S1 and S2 at 15 phr and 50 phr, respectively. It can be seen that, the micrograph of failure surface of Batu Reput filled blends in Figure 1 (A) shows more roughs surface with many tearing lines which means higher energy required to break the samples. Figure 1 (B) illustrated some holes or filler ( Batu Reput ) pull out and with smooth surface indicates a week Batu Reput - interaction due to the bigger size of the filler. However, for Figure 2 (A, and B), as more Batu Reput loading used in Batu Reput filled blends, the blends became stiffer and a brittle failure occurred. It illustrated that, the presence of coarser surface and big holes of Batu Reput on the failure surface indicates a poorer dispersion of Batu Reput inside the blends particularly for Batu Reput filled.

4 A A B B Figure 1: SEM micrograph of tensile surface of (A) Batu Reput filled and (B) Batu Reput filled at 15 phr for S1 A A B B Figure 2: SEM micrograph of tensile surface of (A) Batu Reput filled and (B) Batu Reput filled at 50 phr for S2 Conclusions. The following conclusions can be drawn from this study: i. The incorporation of Batu Reput with smaller size of filler (S1) in and blends enhanced the tensile strength (TS) elongation at break (E b ) and stress at 100% elongation (M100) compared to Batu Reput filled blends at all blend size ratio. ii. The SEM micrograph of tensile fracture surface of Batu Reput filled blends with S1 indicates better dispersion with more matrix tearing compared to all other blend ratios. References [1] Reviewing Rubber: Are We Losing Our Grips?, Journal Of The Departments Of Statistics Malaysia, Volume 2, [2] Ismail, H. & Hashim, A.S. (1998). Pengenalan Penyebatian dan Pemprosesan Getah, 1st edn, Penerbit Universiti Sains Malaysia, Penang. [3] H. Ismail, S. Tan, B.T. Poh, Curing and mechanical properties of nitrile and natural rubber blends. J. Elastomers Plast. 33 (2001) [4] Ng S C, Gan L H. Reaction of natural rubber latex with performic acid. European Polymer Journal, 1981, 17(10): [5] Hashim A S, Kohjiya S. Preparation and properties of epoxidized natural rubber. Kautschuk Gummi Kunststoffe, 1993, 46(3): 208. [6] Gelling I R. Epoxidized natural rubber. Rubber Chemistry and Technology, 1985, 58: 86. [7] Yu H P, Li S D, Peng Z. Preparation and study of epoxidized natural rubber. Journal of Thermal Analysis and Calorimetry, 1999, 58(2):293. [8] Gelling I R. Epoxidized natural rubber. Natural Rubber Research, 1991, 6(3): 184. [9] Baker, C S L, Gelling I R, Newell R. Epoxidized natural rubber. Rubber Chemistry and Technology, 1985, 58(1): 67. [10] Nazry, S.M., Nizar, K., Kamarudin, H., Shamsul, J.B. and Ruzaidi, C.M., (2006). Pencirian Batu Reput di Negeri Perlis Menggunakan XRD Dan SEM. KUKUM Engineering Research Seminar, [11] F. Findik, R. Yilmaz, T. Koksal, Investigation of mechanical and physical properties of several industrial rubbers. Mater. Des. 25 (2004)

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