STUDI PROSES MASTIKASI DAN PENGGILINGAN KARET ALAM PENGARUHNYA TERHADAP KARAKTERISTIK VULKANISASI DAN SIFAT FISIK VULKANISAT
| Main Authors: | , IR. ABU HASAN M.SI., , Prof. Ir. Rochmadi, SU., Ph.D. |
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| Format: | Thesis NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 2013
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/123374/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=63485 |
Daftar Isi:
- Indonesia is the country's largest exporter of natural rubber in the world together with Malaysia and Thailand. The exports include crumb rubber and concentrated latex. Nevertheless, the consumption of natural rubber in the country is still quite small about 17.24% of the total natural rubber production in Indonesia in 2011. Therefore there are many opportunities to develop rubber goods products in the domestic rubber industry, especially for small and medium enterprises (IKM). To improve the nation's competitiveness and transfer of rubber technology, the understanding of rubber technology may be required. Rubber technology includes designing of rubber formulas (recipes), mastication and milling, test of curing characteristics, and testing of physical and chemical properties of vulcanized rubber. Mastication and milling are important to the rubber technology. Preventing premature vulcanization, designing the physical and chemical properties of vulcanized rubber, and forecasting of curing characteristics can be conducted by modifying the process of rubber mastication and milling. The sequence of rubber mastication and milling process has contributed greatly to the curing characteristics and physical properties of vulcanized rubber, rubber formula in addition to design. Therefore the aim of research is to study the process of rubber mastication and milling, and relation to the curing characteristics and the physical properties of vulcanized natural rubber. The steps necessary to achieve the goal of these studies is the design of natural rubber formula, rubber mastication and milling (60°C), curing test (150oC), and perform characterization of compound and vulcanized rubber. The process of rubber mastication and milling was done by several methods, the mixing method of carbon black into rubber in the samples A, B, C and D in the following ratios 10-40, 20-30, 30-20 and 40-10, and the order of carbon black mixing and filler into the rubber performed either simultaneously in samples A (rubber mastication for 5 min, followed by mixing of carbon black N 330 and rubber chemicals in the rubber simultaneously), B (rubber mastication for 1 min, followed by mixing of carbon black N 330 and rubber chemicals in the rubber simultaneously), and C (the process of rubber mastication and mixing with B but are used carbon black N660 type), and in turn on the sample D (rubber mastication for 3 min, mixing of carbon black N 330, followed by the mixing of rubber chemicals in the rubber). Rubber mixing temperature variations (55oC-70oC) in samples B1 and C1, rubber vulcanization temperature variations (140oC-170oC) in samples A1 and D1, and the use of two types of carbon black (N 330 and N660) were also performed. The compound characterization includes the test of Mooney viscosity at 100 ° C (ISO 289-94), bound rubber, filler dispersion (Dino-Lite digital microscope and DisperGrader) and mixing energy while the characterization of vulcanized rubber consists of rheometer test (ISO 6502-99), test of free sulfur (ASTM D 297-93), crosslink density test, and test of the physical properties. The physical properties comprise of hardness (ISO 7619 (1) - 2004), tensile strength, modulus 500 % and elongation at break (ISO 37-2005), tear resistance (ISO 34-2007), abrasion resistance (ISO 4649-2002), and rebound resilience ISO (4662-2009). The relationship between bound rubber and crosslink density was also studied. The method of carbon black mixing into the rubber on the rubber mastication and milling results significant improvement of physical properties in samples A, B, C, and D. The more volume of carbon black is added at the beginning of the process of rubber mastication and milling, the varied physical properties of vulcanized natural rubber were obtained. Besides an increase in some physical properties, there is also a reduction in the physical properties of the samples. Sample D had the highest increase in physical properties compared to samples A, B, and C. Sample D4 (mixing ratio of carbon black 40-10) are sample that have improved physical properties with the highest tensile strength of 271 kg/cm2 compared with samples D1 (black carbon mixing ratio 10-40) which has a tensile strength 270 kg/cm2, D2 (black carbon mixing ratio 20-30) has a tensile strength 259 kg/cm2, and D3 (black carbon mixing ratios of 30-20) has a tensile strength of 267 kg/cm2. The more carbon black is added at the beginning of the process of rubber mastication and milling, the more carbon black can interact with the rubber that is still has a fairly high viscosity. Carbon black aggregates break into smaller particles, so that the surface area of carbon black to be large and cause an increase of bound rubber. The high bound rubber causes the increase of tensile strength. The mixing ratio of carbon black into the rubber on the sample D was also performed on samples A, B, and C. The order of carbon black mixing and filler into the rubber in the process of rubber mastication and milling made in turn or do mixing of carbon black after mastication process, followed by mixing of filler into the rubber (sample D), resulting in improved physical properties better than the sequence of carbon black mixing and filler in the rubber performed simultaneously (samples A, B, and C). For example, the tensile strength of D4 is 271 kg/cm2 and the tensile strength of samples A4, B4 and C4 ranges from 189-256 kg/cm2. The use of carbon black type N 330 resulted in improved physical properties higher than the physical properties obtained by using the carbon black N660 type in the natural rubber formula. Carbon black type N330 has a smaller particle size than that of carbon black type N 660. The smaller the particle size, the larger the surface area of the carbon black per unit of mass, so that the adsorption of rubber molecules on the surface of carbon black increases. The increase of bound rubber causes the effect of the carbon black as reinforcing filler increased. Therefore, the physical properties are great. Milling temperature on the process of rubber mastication and milling also affect the physical properties of vulcanized rubber. The higher the temperature of the rubber milling 55oC - 70oC, the better the physical properties of vulcanized natural rubber, especially on the increase of abrasion resistance (of 147 DINmm3 rose to 150.1 DINmm3) and tear resistance (up from 136 kg/cm2 to 141 kg/cm2). The higher the milling temperature, the lower the viscosity of the rubber so the easier both carbon black and rubber chemicals dispersed into the rubber. Carbon black dispersion effect strengthening while the dispersion of rubber chemicals, especially sulfur causes faster vulcanization reaction. Thus, both abrasion and tear resistance rose from milling temperature of 55oC - 70oC. Temperature affects the rate of vulcanization reaction. Both data derived from observations of free sulfur and data based on rheograf in the vulcanized natural rubber, show that the higher the vulcanization temperature of rubber, the faster the reaction of vulcanization. The higher the temperature of vulcanization in samples A1 and D1, the greater the reaction rate constants, so that the reaction rate increases. For samples D1, tensile strength (259 kg/cm2-248 kg/cm2), modulus 500% (241 kg/cm2-131 kg/cm2), tear resistance (180 kg/cm2-107 kg/cm2), and abrasion resistance (112 DINmm3-115 DINmm3) declines with the increase of vulcanization temperature of 140oC-170oC. Sample A1 has a lower physical properties than that of the sample D1. Tensile strength of sample A1 (270 kg/cm2-245 kg/cm2), modulus 500% (235 kg/cm2-206 kg/cm2), tear resistance (145 kg/cm2-135 kg/cm2), and abrasion resistance (103,9 DINmm3-122,3 DINmm3) decreases with increasing of vulcanization temperature of 140oC-170oC. Vulcanized natural rubber does not withstand at high temperature, leads to the decrease of physical properties in samples A1 and D1. The physical properties of the sample D1 looks bigger than that of the sample A1. The difference in the order of carbon black mixing type N 330 and rubber chemicals in the rubber on samples A1 and D1, leading to differences in the physical properties. In samples D1, carbon black type N 330 was mixed prior to mixing rubber chemicals. The surface of carbon black type N 330 has not been tainted by chemicals rubber so that the physical properties of the sample D1 is higher than that of the sample A1 in which the carbon black mixing type N 330 and rubber chemicals performed simultaneously. It can be concluded that the process of rubber mastication and milling affects the physical properties of vulcanized natural rubber.