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Dwi Wahini Nurhajati
Kementerian Perindustrian
Engineering

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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.
Pengaruh alkali pada pembuatan film pelapis (“coating film”) menggunakan teknologi sinar ultraviolet Dwi Wahini Nurhajati
Majalah Kulit, Karet, dan Plastik Vol 6, No 10-11 (1991): Majalah Barang 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 | Full PDF (1070.739 KB) | DOI: 10.20543/mkkp.v6i10-11.465

Abstract

Coating film in this research is defined as the product of polymerization (crosslinking) of acrylate monomers whit phenol resin directly on substrate via interaction with incide UV irradiation. A thin layer consist of phenol resin (resole or novolac), monofunctional acylate monomer (ECA), and hexafunctional acylate monomer (DPCA-60) gives the crossliked polymer under UV irradiation. In order to enhance the insoluble polymer yield, effect of alkali addition was studied. Ba(OH)2 and KOH are most effective for phenol and novolac, respectively, from the viewpoint of insoluble polymer yield. INTISARIFilm pelapis (“Coating Film”)dalam penelitian ini didefinisikan sebgai hasil polimerisasi (rantai silang) dari monomer-monomer akrilat dengan resin phenol, langsung pada substrat melaluiinsiden irradiasi sinar ultra violet. Lapisan tipis yang terbuat dari campuran resin phenol (resole atau novolak), monomer akrilat monofungsional (ECA) dan monomer akrilat hexafungsiona (DPCA-60) memberikan polimer rantaisilang dengan adanyya irradiasi sinar ultra violet (UV). Dalam hal untuk menaikkan hasil polimer yang tidak larut dalam pelarut, pengaruh alkami sebagai bahan tambahan diteliti.Ba(OH)2 merupakan alkali yang paling efektif untuk phenol resole dan KOH paling effektid untuk novoloak, dalam hal menaikkan hasil polimer yang tidak larut dalam pelarut.
Pengaruh resin resol pada pembuatan film akrilat dengan menggunakan sinar ultraviolet Dwi Wahini Nurhajati
Majalah Kulit, Karet, dan Plastik Vol 4, No 8 (1989): Majalah Barang 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 | Full PDF (874.881 KB) | DOI: 10.20543/mkkp.v4i8.456

Abstract

The aim of this research to investigate photoinitioting ability of resole resin in photocrosslinking of acrylate monomers. In this article, compounds consist of acrylate monomers. In this article, compounds consist of acrylate monomers (ECA and DPCA 60) and resole resin were irradiated with ultraviolet light (120 watt/cm) for 3 times and then analised. Compounds with high resole resin and DPCA – 60 content formed insoluble transparent thin film. It was found that resole resin played an important role in the formation of polymer crosslinked structures in acrylate monomers. However, the value of the insoluble thin film fraction did not greater than 40,16% at present. The highest film fraction was obtained from a compound with resole resin 40 wt. % and DPCA 60 = 60 wt. % content. 
Pemanfaatan karet skrap limbah vulkanisir ban untuk kompon pedal sepeda motor Dwi Wahini Nurhajati
Majalah Kulit, Karet, dan Plastik Vol 25, No 1 (2009): 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 | Full PDF (2334.585 KB) | DOI: 10.20543/mkkp.v25i1.229

Abstract

The utilization of scrap rubber from tyre-retreading industry for footstep compound have been investigated. Pretreatment of rubber scrap with minarex B was done before it was compounded. The footstep compound was designed with various ratio of RSS/pretreated rubber scrap: 100/0; 75/25; 50/50, and 25/75 respectively. The compounds were prepared on a two-rolls mill machine. The compounds were tested for its physical properties such as tensile strength, elongation at break, abrassion resistance, hardness, density, permanent set, and aging, respectively. Test result was compared with physical properties of current commercial footstep. The physical properties of invented footstep compounds were better than current commercial footstep. The footstep compound made by using the RSS and pretreated rubber scrap in ratio of 75/25 performed the best physical properties with 146,48 kg/cm3 tensile strength; 253,36% elongation at break; 58,33 Shore A hardness, 2,91 mm3/kgm abrasion resistance, 1,23 g/cm3 density, 4,69% permanent set, and the change of physical properties after aging at temperature 70oC for 3 x 24 hours were 1,90% tensile strength, 5,02% elongation at break, and 4,04% hardness, respectively. Molding of footstep was done at 150o C, and 150 kg/cm2 for 10 minutes. Organoleptics test showed molded footstep good appearance, good homogeneity during curing, and good flowing compound respectively when it was moulded. Keyword: scrap rubber, waste rubber, tyre-retreading industry, footstep compound, RSS = ribbed smoke sheet ABSTRAKTelah dilakukan penelitian pemanfaatan karet skrap limbah vulkanisir ban untuk kompon diberi perlakuan pendahuluan yaitu dicampur dulu dengan plasticizer minarex B. Kompon untuk pedal sepeda motor dirancang dengan variasi perbandingan ribbed smoke sheet RSS/pretreated karet skrap berturut-turut 100/0; 75/25; 50/50 dan 25/75. Kompon pedal dibuat menggunakan mesin two-roll mill. Kompon pedal yang dihasilkan selanjutnya diuji sifat fisisnya meliputi tegangan putus, perpanjangan putus, ketahanan kikis, kekerasan, berat jenis, pampat tetap, perubahan setelah aging terhadap kekerasan, tegangan putus dan perpanjangan putus. Hasil uji pedal dibandingkan dengan hasil uji pedal sepeda motor komersial di pasaran. Sifat fisis kompon pedal hasil penelitian pada umumnya lebih baik daripada sifat fisis terbaik yaitu tegangan putus 146,48 kg/cm2, perpanjangan putus 523,36%, kekerasan 58,33 Shore A, ketahanan kikis 2,91 mm3/kgm, berat jenis 1,23 g/cm3, pampat tetap 4,69%, dan sifat fisis setelah aging pada suhu 70oC selama 3 x 24 jam memiliki perubahan tegangan putus 1,90%, perpanjangan putus 5,02%, dan kekerasan 4,04%. Pencetakan dilakukan pada tekanan 150 kg/cm2 suhu 150oC selama waktu 10 menit. Secara pengamatan visual pedal sepeda motor yang dihasilkan cukup baik, kematangan merata, kompon dapat mengalir dengan baik dalam cetakan. Kata Kunci : karet skrap, limbah vulkanisir ban, kompon pedal sepeda motor, RSS = ribbed smoke sheet.
Co-Authors Agustin Suraswati Arum Yuniari Ary Achyar Alfa Bambang Priyono Emiliana Kasmudjiastuti Endro Kismolo Gunawan Priambodo Hadi Musthofa Herminiwati Herminiwati Ihda Novia Indrajati Ike Setyorini Kadarijah Kadarijah Made Sumarti Niken Karsiati Penny Setyowati Pramono Pramono Prayitno Prayitno Sri Brataningsih Puji Lestari Suliestiyah Wiryodiningrat Supriyadi Supriyadi Supriyanto B Supriyanto B Umi Reza Lestari Umi Reza Lestari