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Abstrak :
ABSTRAK
Baja karbon adalah jenis material baja yang cukup mudah diperoleh dan banyak digunakan sebagai komponen struktural. Namun jika digunakan di lingkungan terbuka, misal untuk infrastruktur di laut, baja karbon rentan terhadap serangan korosi atmosferik dan biofouling terutama pada kondisi lingkungan dengan polutan yang tinggi. Metode pengecatan adalah salah satu bentuk perlindungan untuk baja karbon terhadap serangan korosi di lingkungan laut. Penelitian ini menginvestigasi daya lekat dan kemampuan perlindungan korosi dari tiga sistem cat multilapis yang umum diaplikasikan pada struktur baja di laut, terdiri dari cat zinc-rich, epoxy, polyurethane dan silyl acrylate anti-fouling. Metode pengujian mencakup uji tarik cat, pengukuran EIS dan polarisasi, uji celup, uji sembur garam, serta pengamatan makro dan karakterisasi SEM/EDS, yang seluruhnya dilakukan dalam kurun waktu 4 bulan. Hasil penelitian menunjukkan bahwa sistem cat inorganic zinc silicate epoxy mastic dan zinc-epoxy epoxy mastic polyurethane memiliki ketahanan korosi yang baik mdash;terutama di lingkungan atmosferik mdash;dengan mekanisme proteksi gabungan barrier dan galvanik. Sedangkan sistem cat epoxy primer polyurethane anti-fouling memiliki kekuatan adhesif dan ketahanan korosi yang buruk, namun efektif dalam menangkal penempelan fouling di lingkungan terendam.

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ABSTRACT
Carbon steel is a type of steel that is widely available and employed as a structural component. However, if used in open air environments, for example for marine infrastructure, carbon steel is susceptible to atmospheric and biofouling corrosion especially in highly polluted environments. Painting method is one form of protection for carbon steel against corrosion attacks in the marine environment. This study investigates paint adhesion and corrosion protection performance of three multilayer paint systems commonly applied to marine steel structures, comprising zinc rich, epoxy, polyurethane and silyl acrylate anti fouling paints. The test method encompassed the pull off test, EIS and polarization measurements, immersion test, salt spray test, and macroscopic observation and SEM EDS characterization, all of which were carried out over a period of 4 months. The results exhibited that the inorganic zinc silicate epoxy mastic and zinc epoxy epoxy mastic polyurethane paint systems has good corrosion resistance mdash particularly in atmospheric environments mdash by incorporating barrier properties and galvanic protection mechanisms. While the epoxy primer polyurethane anti fouling paint system has poor adhesive strength and corrosion resistance, it is effective in preventing fouling attachment in submerged environments.

Abstrak :
Dalam studi ini, campuran Chlorinated Rubber (CR), Polydimethylsiloxane (PDMS) dan Grafena Oksida (GO) diteliti secara sistematis untuk diusulkan sebagai aditif anti-fouling dalam poliuretan (PU). Peningkatan kekuatan tarik diperoleh dengan penambahan campuran CR dan PDMS:GO. Spektrum Forier Transform Infra-red menunjukkan penurunan intensitas regangan ikatan rangkap C=C dan memunculkan ikatan Si pada senyawa kimia PU. Untuk mengetahui peran fungsi anti-fouling, sampel direndam di laut selama dua bulan. Selanjutnya sampel yang direndam di laut dikarakterisasi menggunakan mikroskop optik dan pengujian mekanik. Pengamatan mikroskop optik diperoleh bahwa penambahan CR mengurangi pertumbuhan teritip mikro dan penambahan PDMS:GO menurunkan pertumbuhan alga mikro. Untuk penelitian lebih lanjut, pengukuran Electrochemical Impedance Spectroscopy (EIS) dikembangkan untuk mengetahui spektrum impedansi sampel sebelum dan sesudah perendaman dalam air distilasi. Hal ini menunjukkan bahwa impedansi total berubah dengan perendaman. Elemen rangkaian ekivalen dari spektrum impedansi dimodelkan untuk mengekstrak resistansi seri, resistansi paralel, dan kapasitansi. Menariknya, resistansi seri, resistansi paralel dan kapasitansi berubah secara konsisten yang menunjukkan kemungkinan pelepasan elemen anti-fouling selama perendaman untuk setiap sampel. Selanjutnya dilakukan uji pelapukan di bawah sinar ultraviolet (UV) selama 500 jam untuk mengetahui kerusakan sifat mekanik. Hasil pengamatan menunjukkan bahwa pada awal paparan sinar UV hingga 80 jam kuat tarik meningkat signifikan. ......In this study, a mixed chlorinated rubber (CR), polydimethylsiloxane (PDMS) and graphene oxide (GO) was systematically investigated to propose as anti-fouling additives in polyurethane (PU). The increasing of tensile strength were observed by the addition of the mixture of CR and PDMS:GO. The Fourier transform infra-red spectra showed the decreasing of a C=C strain group and increasing Si bond of chemical compounds of PU, respectively. In order to investigate the role of the anti-fouling function, the samples were immersed in the sea for two months. Further the immersed samples in the sea were characterized using optical microscope and mechanical testing. The optical microscope observation obtained the addition of CR reduced the growth of micro barnacle and the addition of PDMS:GO decreased the growth of micro algae. To more elaboration, the electrochemical impedance spectroscopy (EIS) measurement was developed to investigate the impedance spectra of the samples before and after immersion in distilled water. It showed that the total impedance changed by the immersed samples. The equivalent circuit element from the impedance spectra was modelled to extract the series resistance, parallel resistance and capacitance. Interestingly, the series resistance, parallel resistance and capacitance were changed consistently which indicated the probably of the anti-fouling element release during the immersion for each sample. Furthermore, the ageing test under ultraviolet (UV) light was performed for 500 hours to investigate the decay of the mechanical properties. It was observed that the UV light ageing initially increased the tensile strength until of 80 hours exposure.

Abstrak :
ABSTRAK
In this study, characterization of fatty acids in Dictyota dichotoma and Sargassum granuliferum, the sea-weeds collected from Pulau Nuyunan, Sabah, were carried out. fatty acid methyl-ester analysis (FAME) showed palmitic acid, elaidic acid, stearic acid, cis- 11,14,17-eicosatrienoic acid and erucic acid were dominant in both seaweeds with co poly- and mono-unsaturated fatty acids were higher than the saturated fatty acids. The pure compounds isolated from Sargassum granuliferum were hexadecanoic acid, pentadecanoic acid, docosanoic acid, tetracosanoic acid, octadecanoic acid, eicosanoic acid and oleamide. Meanwhile, hexadecanoic acid, tetradecanoic acid and 2-hydroxyhexadecanoic acid were isolated from Dictyota dichotoma. All fatty acids isolated exhibited anti-fouling properties with broader activities shown for hexadecanoic acid and fatty acids isolated from Sargassum granuliferum and also more superior than Dictyota dichotoma.