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All Journal Majalah Kulit, Karet, dan Plastik
Umi Reza Lestari
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Engineering

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High-density thermoplastic vulcanizates based on LLDPE/NR for truck floor mats application Dwi Wahini Nurhajati; Umi Reza Lestari
Majalah Kulit, Karet, dan Plastik Vol 37, No 2 (2021): Majalah Kulit, Karet, dan Plastik
Publisher : Center for Leather, Rubber, and Plastic Ministry of Industry, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20543/mkkp.v37i2.7159

Abstract

The use of thermoplastic vulcanizates (TPVs) that was obtained from a blend of thermoplastics and natural rubbers are considered suitable for the automotive applications purpose. To modify the performance of TPVs to a high density TPVs, the high density filler such as bismuth oxide (Bi₂O₃) was added. The focus of this study was on the development of a high density TPVs based on linear low density polyethylene (LLDPE)/natural rubber (NR) blend with different proportions of Bi₂O₃ filler that meets with requirements for truck floor mats materials. The high density TPVs were prepared by melt blending in a Kneader. Bismuth oxide  filler loading was varied by 50; 150; 200; 250 phr and 300 phr. An increase in the weight load of bismuth oxide in TPVs increase density, hardness, and volume loss but reduce the tensile properties, tearing strength, and burning rate of high density TPVs. The test results showed that the TPVs containing 250 phr Bi₂O₃ was a promising candidate for use as a truck floor base.
Characterization of ethylene–vinyl acetate (EVA)/modified starch expanded compounds for outsole material Dwi Wahini Nurhajati; Umi Reza Lestari; Gunawan Priambodo
Majalah Kulit, Karet, dan Plastik Vol 37, No 1 (2021): Majalah Kulit, Karet, dan Plastik
Publisher : Center for Leather, Rubber, and Plastic Ministry of Industry, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20543/mkkp.v37i1.6916

Abstract

The use of non-biodegradable material in shoe components has negative impacts on environmental sustainability when disposed into landfills due to poor biodegradability. This study prepared ethylene–vinyl acetate (EVA)/modified starch expanded compounds as outsole material to overcome environmental pollution. This research aimed to investigate the effects of EVA/modified starch ratio on the properties of the compound. Ethylene-vinyl acetate (EVA) copolymer was blended with a modified cassava starch in various amounts (10-50 phr) using a two-roll mill. Effect of modified starch content was characterized its tensile strength, elongation at break, tearing strength, 50% permanent set, density, abrasion resistance, flex resistance, biodegradability, and morphology.  The optimum value of tensile strength (61.33 kg/cm²), elongation at break (895%), and tear strength (16.62 N/mm) were obtained for samples containing 20 phr modified starch. The EVA compound containing 30 phr of starch showed the optimum 50% permanent set  (4.85%) and the highest abrasion resistance with the smallest volume loss of 439.99 mm³. The addition of modified starch up to 50 phr provided good flexural resistance to 150000 number of cycles. The morphology image showed that distribution of modified starch particles was not homogeneously dispersed in the EVA/modified starch expanded compound. Incorporation of modified starch in EVA compound was improving its biodegradability.
Effect of Bi2O3 on the properties of linier low density polyethylene (LLDPE)/natural rubber compound (NRC) composites Dwi Wahini Nurhajati; Umi Reza Lestari; Ike Setyorini
Majalah Kulit, Karet, dan Plastik Vol 36, No 1 (2020): Majalah Kulit, Karet, dan Plastik
Publisher : Center for Leather, Rubber, and Plastic Ministry of Industry, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20543/mkkp.v36i1.6128

Abstract

The use of thermoplastic natural rubber (TPNR) has spread for many applications such as in footwear, hoses, seals, and automobiles. This increase is in line with the environmental awareness to produce materials that can be recycled. In this paper, the making of TPNR for car floor mat was studied. Bi2O3 filler was added to modify the performance of TPNR for car floor mat. In this study, the effects of Bi2O3 filler on the properties of linear low-density polyethylene (LLDPE)/natural rubber (NR) composites had been investigated. The weight ratio of LLDPE/NR was varied at 90/10; 80/20; 75/25; and 70/30. Bi2O3 filler loading was varied at 0; 20; 40; and 50 phr. The increase in NR and Bi2O3 filler reduced the tensile strength, elongation at break, and tear resistance, but increased the hardness and density of the composites. Compared to similar imported products, the samples prepared in this study showed higher values for all mechanical properties (tensile strength, elongation at break, tear resistance) but lower values in density. Scanning electron microscopy (SEM) micrograph of LLDPE/NR 75/25 composites either with or without the addition of 20 phr Bi2O3 filler displayed homogeneity of the mixture.
Co-Authors Dwi Wahini Nurhajati Dwi Wahini Nurhajati Gunawan Priambodo Ike Setyorini