Journal Majalah Kulit, Karet, dan Plastik

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363 articles
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Arum Yuniari, Hesty Eka Mayasari, Ike Setyorini
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i2.3265

Abstract:The use of methyl methacrylate butadiene styrene (MBS) as a compatibilizer for natural rubber (NR) and nitrile butadiene rubber (NBR) blends has been investigated. Research on the cure characteristics, mechanical properties, swelling, and morphology (SEM) has been conducted to determine the compatibility of NR/NBR blends in the presence of MBS. Based on the cure characteristics, it is indicated that the presence of MBS was affected significantly by maximum and minimum torque. The addition of MBS improved the mechanical properties and the oil resistance of NR/NBR blends due to the compatibility and better interfacial adhesion between rubber phases. The experiment showed that MBS loading by 2.5 phr was the optimum level for NR/NBR blends.
Ike Setyorini, Arum Yuniari
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i2.3345

Abstract:Different ethylene propylene diene monomer (EPDM) composite with the carbon black (CB) variation of 50, 60, and 70 phr (per hundred rubbers) is compounded by using an efcient (EV), semi-efcient (SEV), and conventional (CV) sulfur vulcanization systems. This research aims to investigate the effect of vulcanization systems and carbon black content on the vulcanization rate constant, the crosslink density, and the free sulfur content. This research shows the EV system resulting in the fastest vulcanization rate constant (0.0191/second), the lowest overallcrosslink density (0.0022 mol.cm-3), and the highest percentage of free sulfur content in the EPDM vulcanization (0.40 %). The CV system provides the slowest vulcanization rate constant (0.0061/second) and the highest overall crosslink density (0.0034 mol/cm-3). The percentage of free sulfur content in the EPDM vulcanization of CV system is between EV and SEV systems. The SEV system provides the vulcanization with the characteristic of vulcanization rate constant and overall crosslink density between EV and CV systems as well as provides the lowest percentage of free sulfur content (0.29 %). The higher carbon black loading in each vulcanization systems means the lower rate constant of vulcanization and the higher overall crosslink density.
Prayitno Prayitno, Dona Rahmawati, Gresy Griyanitasari
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i2.3336

Abstract:Sheep wool waste discharged from leather tanning industry recently has posed a problem in relation to its treatment because of its sizeable quantity and its difficulty to degrade. Wool is composed mainly of keratin. It is a protein with a high content of disulfide bonds which cause the protein keratin cannot dissolve in water and resist of diluted acids and alkalis. Keratin can be hydrolyzed to produce keratin hydrolysates which have many benefits such as for cosmetic additives. Research into the use of waste wool of sheep originated from the sheep leather tanning industry had been performed by using a hydrolyzed system to produce protein keratin. The waste wool used came from unhairing by painting and conventional unhairing. Hydrolysis was done using hydrogen peroxide 50% amounting to 70 ml for every 40 gr of wool. Hydrogen peroxide was added to wool immersed in the 0.5 M NaOH solution for three hours. The length of hydrolysis ranged from 4, 5, to 6 hours and the mix was stirred shortly every 1 hour followed by filtration using a coarse sieve. To precipitate the hydrolyzed keratin, the pH was decreased to 4-5 using the 2 M HCl solution and after separation of the precipitation, it was dried in the oven at a temperature not more than 50 oC for 2 days. The research findings showed that a maximum of 69.19% of keratin hydrolysates was generated using the raw material of waste wool through a conventional process with a total of hydrolysis time by 6 hours, whereas the maximum protein generated was 66.99% using waste wool through a conventional process with a total of hydrolysis time by 4 hours. The FTIR test showed the presence of groups of amides, cysteic acids, and cystine-S-monoxide.
Santi Puspitasari, Adi Cifriadi
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i2.3327

Abstract:Peningkatan ketahanan oksidasi termal karet alam dapat memperluas aplikasinya terutama untuk pembuatan produk karet yang diaplikasikan di luar ruangan. Karet alam tahan oksidasi termal dapat dibuat secara transfer hidrogenasi menggunakan senyawa diimida yang dihasilkan secara insitu dari oksidasi hidrasina hidrat oleh hidrogen peroksida. Pada riset ini dipelajari kondisi optimum reaksi transfer hidrogenasi lateks karet alam pada skala semi pilot berkapasitas 2,5 kg lateks pekat/batch berkatalis asam borat. Sistem kestabilan koloid lateks selama reaksi dipertahankan dengan penambahan kombinasi surfaktan anionik/nonionik. Variabel yang ditetapkan dalam reaksi meliputi suhu (40 dan 50oC) dan rasio konsentrasi hidrasina hidrat (40 dan 42,5 phr) terhadap hidrogen peroksida (30 dan 35 phr). Berdasarkan hasil analisis kualitatif dan kuantitatif terhadap karet terhidrogenasi diketahui bahwa kondisi optimal reaksi transfer hidrogenasi lateks karet alam dicapai pada suhu 50oC dengan rasio konsentrasi hidrasina hidrat/hidrogen peroksida sebesar 42,5/35 phr. Pada kondisi reaksi tersebut, karet terhidrogenasi memiliki sifat ketahanan oksidasi termal yang lebih baik dibandingkan karet alam murni yang ditunjukkan dengan wujud bertekstur kokoh, keras, dan tidak lengket, indeks ketahanan plastisitas tertinggi sebesar 38,5% dan derajat hidrogenasi sebesar 60,48%. Karet hidrogenasi tersebut juga memiliki kadar gel yang rendah sebesar 56,98%.
Ahmed Ibrahim Nasr
Majalah Kulit, Karet, dan Plastik, Volume 33, pp 99-107; doi:10.20543/mkkp.v33i2.3139

Abstract:The objective of this study is to investigate the influence of using some mechanical finishing processes on final properties of produced leather types. Nappa, nubuck, pigmented and corrected grain leather types were produced by applying some of the following operations: hang drying, vacuum drying, molissa staking, drum milling, buffing, spraying and/or embossing surface with extreme pressure. Hydrophobic-hydrophilic status, scanning electron micrographs, organoleptic and mechanical properties were determined on all finished leather types. Results showed that water behavior was hydrophobic for nappa leathers, while it was hydrophilic with the rest of produced leather types. Buffing surface in nubuck leather increases the water absorption and water vapor permeability, while the opposite was found when applying external coat layer in pigmented and corrected grain leathers. Applying vacuum drying in nappa leathers increases surface smoothness and surface water contact angle while decreases tensile and tearing strengths. These results elucidate that all studied leather types are suitable for manufacturing purposes except nubuck leather which is not recommended for footwear uppers manufacturing due to its high water absorption. The present study emphasized that while mechanical finishing processes could have profound effects on leathers surface behavior, they must be adequate to the requirements and properties of the end products.
Ahmed Ibrahim Nasr, Mohamed Gaber Taha, Hany Y Yosef, Mohamed A El-Shaer
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i2.3018

Abstract:Massive quantities of rice straw are burned annually in Egypt and caused environmental hazards. The present study investigated the utilization of rice straw to produce sodium lignosulphonate (SLS) as a water-soluble derivative of lignin in leather tanning and evaluate its usage as a tanning or re-tanning material as well as its effect on leather quality. The results of testing SLS as a leather tanning agent were unsatisfactory due to its slight effect on shrinkage temperature of leathers, unlike its use as a re-tanning material. Four concentrations of SLS (0%, 5%, 10%, and 20%) were used in re-tanning forty of sheep wet-blues. The results showed that using SLS as a re-tanning agent with concentration till 10% from pelts weight enhances some organoleptic properties, such as fullness and general appearance together with slight improvement in physical properties of leathers. Moreover, the addition of SLS with concentration 20% led to an excessive swelling in the collagen fibers as shown from depicted scanning electron micrographs and decreased trends of physical properties.
Tengku Rachmi Hidayani, Elda Pelita, Gusfiyesi Gusfiyesi
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i1.2202

Abstract:This research aimed to overcome the issue of plastic packaging waste that accumulates in nature because synthetic polymers cannot be easily unraveled by bacteria. Biodegradable plastics were produced by mixing waste of plastics of the low density polyethylene (LDPE) with starch of empty palm fruit bunches, modified with the addition of maleic anhydride as a crosslinking agent. To produce biodegradable plastics, different compositions of LDPE waste, starch of empty palm fruit bunch, maleic anhydride, and benzoyl peroxide were used, namely (90: 10: 1: 1), (80: 20: 1: 1), (70: 30: 1: 1), and (60: 40: 1: 1). Research stages consisted of extraction of starch from palm empty fruit bunch (PEFB); preparation of biodegradable plastic powder with the reflux method and xylene solvents; and making of biodegradable plastics using the press molding method. Based on the results of characterization, it was revealed that the optimum condition was generated by biodegradable plastics with the composition of LDPE waste, starch of empty palm bunches, maleic anhydride, and benzoyl peroxide was equal to 60: 40: 1: 1, which generated the tensile strength value of 6.9410 N/m2, the elongation at break of 3.1875%, the the melting point temperature of 103oC, and the decomposition temperature of 384oC. Besides, the thermal gravimetric test generated a residue of 12.6% and results of the analysis on morphological properties suggested that the starch distributed evenly.Keywords: Biodegradable plastics, LDPE waste, LDPE-g-MA, starch, palm empty fruit bunch.
Suharman Suharman, M. Harun
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i1.2123

Abstract:This research aimed to make natural rubber-based gas cylinder seals with quartz sand as the filler to replace carbon black. The experiments consisted of the use of 10 phr, 20 phr, 30 phr, 40 phr, and 50 phr of quartz sand. The gas cylinder seals produced underwent a test according to the Indonesian National Standard (SNI) 7655:2010. The test generated the following results: the value of hardness ranged from 51±6 to 60±5 Shore A, the value of tensile strength ranged from 67 to 72 kg/cm2, the value of elongation at break ranged from 414 to 457%, the value of the compression set ranged from 25 to 61%, after aging, and ozone resistance with no cracks. Natural rubber-based gas cylinder seals with quartz sand as the filler to replace carbon black met the requirements specified by SNI 7655:2010 in terms of the criteria of hardness, elongation at break, after aging and ozone resistance.Keywords: quartz sand, carbon black, gas cylinder seal.
Dwi Wahini Nurhajati, Muhammad Sholeh, Ihda Novia Indrajati, Ike Setyorini
Majalah Kulit, Karet, dan Plastik, Volume 33; doi:10.20543/mkkp.v33i1.2770

Abstract:This research aimed to determine the effects of the addition of glass fibers on the physical and crystallinity properties of PC/ABS polyblends. The ratio of PC/ABS used in this research was 75/25, while the addition of glass fibers ranged from 0; 5; 10; to 15 phr (based on the weight of PC/ABS). Polyblends of PC/ABS/glass fibers were prepared in a twin screw extruder. The test results showed that density and tensile strength of PC/ABS polyblends increased with an increase in the glass fiber content. The presence of glass fibers decreased MFI and impact strength of these PC/ABS polyblends. The functional groups were determined by the fourier transform infrared (FTIR) spectrophotometer while crystallinity was examined using X-ray diffractometer (XRD).Keywords: PC/ABS polyblend, glass fiber, physical properties, crystallinity.
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