Judul: Pengaruh Penambahan Senyawa Merkaptan Pada Karet Alam (Hevea Brasiliensis) Dalam Fasa Padat
Abstrak: Natural rubber had increasing viscosity while in transportation process and storage. This natural phenomenon called hardening, storage hardening, the process that happen in storage caused by cross bonding reaction in poly isoprene molecular chain with the aldehide that condense in non rubber substances or in rubber polymer chain. This symptom give disadvantages for consumer in processing rubber based products. To overcome this problem, the addition of rubber viscosity stabilizer could block the form of cross bonding on rubber molecular chain Stabilized viscosity rubber demand by the consumers because with the stabilized viscosity the premastication process is unnecessary, this process consumed 33-35% of the total energy needed to make rubber compound. Processing without the premastication will increase almost twice of the capacity in compound mixing. Besides it will also increase the consistency in compund mixing and viscosity of the rubber compound. The effect will reduce the scrap amount in processing rubber based product. The purpose of this research is to learn the effect of rubber viscosity stabilizer addition to the rubber stability with the variation of Cureo TS addition dosage, extruder temperature and time variation. The Cureo dosages that were used are 0%, 5%, 10%, and 15%. The main research designated to find the effect of Cureo TS addition on temperature addition (100oC, 120oC, 140oC) and time (3 minute, 4 minute, 5 minute) to the rubber stability. The test that done were chemical characteristics includes Po (Early Plasticity) and Pa (End Plasticity); PRI (Plasticity Retention Indeks); dan ASHT (Accelerated Strorage Haredening Test). The phisical characteristics test wit the Mooney viscosity test. Until now there no riset about the addition of Cureo TS as a stabilizer in rubber. The decision on using Cureo TS as stabilizer because it can react with the carbonyl group whether with the aldehide or keton. Reaction between merkaptan with the carbonyl group happen in two steps. The early product of the reaction is the hemi merkaptal or hemi merkaptol will react with the merkaptan group,either it is spontaneously or using catalyst to produce merkaptal or merkaptol. Rubber particle in latex contain aldehid group that bound to the cis-poly isoprene chain of rubber. The aldehid group in rubber expected to reacted with the merkaptan group that ussually added to rubber as peptizer. The aldehid group will react with merkaptan and form hemi merkaptal. Hemi merkaptal will react with merkaptan and form merkaptal. In the making of stabilized viscosity rubber, merkaptan usually contained in peptizer with the trade name Cureo TS. If in the rubber processing peptizer used as softener than the indirect use of peptizer could make the rubber stabile because the tiol group will blockade the aldehid group to form tioacetal, so there will be no gel forming. This will cause the rubber viscosity no increasing while in storage so the rubber becomes stabile. From the data it was found that from all treatment the Po number between 43 until 53. While the Po number for control are between 46.5 until 53. This number show that the Po number decrease compare with the control. The decreasing of Po number
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Judul: Pengaruh penambahan hidroksilamin netral sulfat HNS terhadap kadar nitrogen dan kemantapan viskositas mooney lateks berprotein rendah
Abstrak: Karet alam digolongkan ke dalam kelompok elastomer untuk penggunaan umum karena dapat digunakan sebagai bahan baku berbagai jenis industri seperti industri ban, cat, pelapis, perekat dan sebagainya. Peningkatan kebutuhan karet alam sebagai bahan baku industri menuntut produsen untuk menghasilkan karet alam dengan mutu yang lebih baik, diantaranya karet alam dengan kadar protein rendah dan viskositas Mooney yang mantap. Karet alam yang mempunyai kadar protein rendah lebih mudah diproses, mempunyai stabilitas mekanis yang lebih tinggi, serta dapat mengurangi efek alergi terhadap karet alam (Tanaka et al., 1996 dan Nakade et al., 1997). Salah satu produk hasil penurunan protein karet alam adalah lateks berprotein rendah (lateks DPNR) yaitu lateks alam yang kadar nitrogennya telah diturunkan semaksimal mungkin melalui proses deproteinasi. Namun lateks DPNR yang telah dihasilkan masih memiliki viskositas Mooney yang tinggi karena terjadinya ikatan silang secara perlahan pada rantai polimer karet yang dapat menghambat proses modifikasi karet alam dan menurunkan kelarutan karet siklo sebagai bahan baku perekat. Perlakuan kimia perlu dilakukan untuk menghasilkan lateks DPNR dengan viskositas Mooney yang mantap yaitu penambahan larutan Hidroksilamin Netral Sulfat (HNS) ke dalam lateks DPNR. HNS dapat mencegah terjadinya ikatan silang pada gugus aldehida-aldehida pada rantai polimer karet yang menyebabkan terjadinya pembentukan gel, sehingga peningkatan viskositas Mooney karet alam dapat dicegah. Tujuan umum penelitian ini adalah memperbaiki karakterısisasi lateks DPNR dengan penambahan HNS pada fasa lateks, sedangkan tujuan khusus penelitian ini adalah mengetahui pengaruh penambahan HNS terhadap viskositas Mooney lateks DPNR dan menentukan konsentrasi HNS yang efektif untuk mempertahankan kemantapan viskositas Mooney DPNR melalui pemakaiannya pada fasa lateks. Penelitian ini terdiri dari dua tahap, yaitu penelitian pendahuluan dan penelitian utama. Penelitian pendahuluan terdiri dari dua tahap. Tahap pertama yaitu pengamatan pengaruh dosis surfaktan Emal terhadap kestabilan lateks. Dosis surfaktan Emal yang digunakan pada penelitian ini adalah 0,00 bsk (kontrol), 1,00 bsk, 1,25 bsk, 1,50 bsk, 1,75 bsk, 2,00 bsk, 2,25 bsk, dan 2,50 bsk masing-masing dengan dosis papain yang sama yaitu 0,05 bsk. Dosis surfaktan Emal yang efektif mempertahankan kestabilan lateks hingga tahap pemekatan adalah 2,00 bsk. Tahap selanjutnya adalah pengamatan pengaruh dosis enzim papain terhadap kadar nitrogen lateks. Dosis papain yang digunakan pada tahap deproteinasi lateks adalah 0,00 bsk (kontrol), 0,04 bsk, 0,05 bsk, 0,06 bsk, dan 0,07 bsk dengan dosis surfaktan Emal 2,00 bsk. Papain dengan dosis 0,06 bsk paling optimal menurunkan kadar nitrogen lateks DPNR dari 0,52% hingga 0,04%. ...
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Judul: Etno-ornitologi Burung Kancilan Flores (Pachycephala nudigula nudigula Hartert 1897) pada Masyarakat Lio di Taman Nasional Kelimutu
Abstrak: Bare-throathed whistler is one of several wild birds in Kelimutu National Park (TNKL) that is believed to have correlation with Lio Community‟s belief. The estimation of Bare-throated whistler‟s population in Kelimutu National Park was about 186.41-1668.07 individual by the density about 0.0389-0.3481 ind/ha with the sex ratio 6.2:1 that spreaded on area with height of 1100 – 1600 masl. The characteristic of Bare-throated whistler‟s habitat is a natural forest with various canopy level, high plant species diversity and high density. The habitat characteristics related to the availability of food in the form of insects, cover, safety and a nesting site. Generally the most of Lio community knew the existence of Bare-throated whistler directly or from their parents‟ stories. The perceptions of Lio Community to the Bare-throated whistler‟s existence is generally support the conservation efforts. The perceptions construct the Lio Community‟s atitude that tend to be conservative to the existence of Bare-throated whistler. The attitude shown by their behavior that not cathing the Bare-throated whistler from the TNKL‟s area or the outside. The attitude have an important role to the existence of Bare-throated whistler in Kelimutu National Park‟s area.
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