Influence of weathering effect in natural environment on thermal properties hybrid kenaf blast/glass fibre and unsaturated polyester composite M Mohammed, A R Rozyanty, B O Beta et al. (10, 20, 30, 40,and 80 wt.%) using mechanical blending method. The blends were cured at room temperature using methyl ethyl ketone peroxide (MEKP) (4 wt.%) as catalyst initiator without the presence of catalystaccelerator. The effect of vinyl ester composition on theenhancement of mechanical and thermal properties of unsaturated polyester/vinyl ester blends was investigated.The polymer blends were characterized by Fourier Transform Infra Red (FTIR)spectroscopy, tensile testing, hardness testing, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). IR spectra showed UP and VE peaks. The curing copolymerization reactionoccurred at vinyl (C=C) bonds. The addition of vinyl esters enhanced mechanical and thermal properties. The UP/VE blends showed homogeneous morphology, transparent and copolymer thermoset blend.Keywords: unsaturated polyester, vinyl ester, polymer blend, thermal properties IntroductionUnsaturated polyester is a widely used thermosetting resin. Unsaturated polyester has a reactive vinyl (carbon-carbon double) bond. Styrene is added to unsaturated polyester as asolvent and acrosslinking agent for curing reaction. The organic peroxide is used to initiatethe reaction. Organic salt isadded to accelerate the reaction. The polymer is achieved as a result of random condensation copolymerization reaction between styrene and unsaturated vinyl double bonds by free radical mechanismforming crosslinked network structure [1,2]. Unsaturated polyester is a resin (prepolymer) with low price, light weight, easy processing and water resistance. Unsaturated polyester commonly used in laminating resin, composites, coating, adhesive, microelectronic, aerospace, building, automotive, and shipbuilding. However, unsaturated polyester shows limited mechanical and thermal properties. It is necessary to enhance the properties of unsaturated polyester.The properties of unsaturated polyester have been enhanced by theadditionof carbon fiber , fly ash, carbon nanotube, and polyamide [3][4][5][6]. Vinyl ester is an attractivehigh-performance thermoset polymer. Vinylester has reactive double bonds with rigid epoxy structure. Vinyl ester is synthesized by the reaction of epoxy with methacrylic
Boiler memiliki peranan penting di dalam pembangkit listrik tenaga uap di indonesia. Pada pipa boiler sering terjadi kegagalan terutama pada pipa superheater. Superheater ini merupakan komponen dimana uap air dipanaskan sampai temperatur tinggi sehingga memiliki tekanan yang cukup untuk menggerakan generator pada PLTU. Superheater mengalami kerusakan berupa pecah ke luar (burst) dikarenakan penipisan pipa. Kegagalan ini terjadi setelah pemakaian selama 12,8 tahun. Dari hasil pengujian komposisi diketahui bahwa pipa superheater ini merupakan alloy Steel dengan tipe ASTM A213 grade T11. Hasil metalografi menunjukan struktur mikro pada material ini adalah ferit dengan ukuran butir pada daerah yang rusak lebih besar daripada daerah yang masih baik. Pada hasil metalografi juga ditunjukan dengan adanya void dan crack yang muncul pada batas butir. Pada pengujian hardness diketahui bahwa daerah masih baik memiliki kekerasan rata-rata 52 HRB dan pada daerah yang mengalami kerusakan memiliki hasil uji kekerasan rata-rata sebesar 25,5 HRB. Dari data SEM diketahui berkas patahan yang terjadi merupakan patah ulet dan terdapat intergranular crack pada permukaan. Adanya Thermal Fatigue menyebabkan adanya creep sebagai sumber terjadinya kegagalan material Kata kunci-Superheater, shutdown, kerusakan , Alloy Steel, burst.
Reformer biasanya dipakai pada industri Petrokimia untuk menghasilkan hidrogen. Salah satu permasalahan kerusakan/kegagalan yang terjadi adalah pada bagian Tube reformer yang disebabkan oleh pengoperasian pada pengaruh temperatur tinggi. Kegagalan yang terjadi pada tube reformer yang secara visual yaitu adanya crack pada bagian permukaan OD. Analisis yang akan dilakukan yaitu ada 5 pengujian antara lain SEM, Uji tarik, Uji Kekerasan, Uji Komposisi, dan Metalografi. Didapatkan bahwa kegagalan disebabkan oleh overheating yang menyebabkan terjadinya crack yang terdapat pada batas butir. Dari hasil pengujian metalografi ditemukan adanya void-void dan microcrack. Timbulnya void ini disebabkan oleh overheating dan menyebabkan nilai hardness yang tinggi, nilai hardness yang tinggi juga didukung oleh hasil dari EDX, hasil EDX menunjukkan adanya unsur kromium yang tinggi sehingga material menjadi getas. Void yang terdapat pada material HP modified mempengaruhi hasil dari tensile dikarenakan void membuat nilai tensile menjadi rendah. Dari hasil Uji komposisi didapatkan bahwa terdapat unsur yang tidak sesuai seperti Sulfur dan Pospor yang dapat menurunkan sifat dari ketahanan pada temperature tinggi.
Kondisi air yang keruh di kawasan Surabaya utara mengakibatkan masyarakatnya tidak bisa menggunakan air tersebut untuk keperluan sehari-hari. Kondisi ini disebabkan karena Surabaya utara merupakan kawasan dekat pantai, adanya pencemaran dari limbah industri dan limbah rumah tangga. Sehingga diperlukan teknologi pengolahan air bersih untuk mengolah air tanah menjadi air bersih. Metode pelatihan yang digunakan adalah presentasi materi dan demostrasi pengolahan air bersih. Untuk mengetahui kompetensi peserta pelatihan dilakukan ujian pretest dan postest. Hasil pelatihan ini menunjukan adanya peningkatan kompetensi, wawasan dan pemahaman Guru dan Siswa SMA Luqman Al-Hakim mengenai proses pengolahan air bersih, hal ini dibuktikan dengan peningkatan nilai dari ujian Pretest dan Postest.
The crucial manufacturing process in powder metallurgy (PM) is the mixing process. This process ensures blending sufficiently to achieve a uniform and consistent product. Various mixing parameters provide an impact on product properties and fluency during the mixing process. The mixing speed is the most considered parameter which affects the homogeneity and properties of the PM product. The powder of 89,95% wt Cu and 10%wt Sn was mixed at 14, 22, 30, 38 rpm respectively for 120 minutes using a double cone mixer to obtain homogeneity pow-der mixture at 40% filling rate mixer. The mixed powder was compacted at 700 MPa in the 4-column compacting machine. Green compact product was sintered at 200°C for 20 minutes. Sintered specimens were investigated on densification and hardness test. The microstructure was investigated by SEM/EDX and X-ray diffraction. The result showed that the Cu particle form to flake shape, while the Sn particle tends to form irregular rod-like. Particle size on Cu-Sn composite most being finer along with increasing mixing speed. Homogenously distributed dispersed Cu and Sn particles can be achieved successfully at 30 rpm. Furthermore, the hardness test value was 94,2 HRF. The density was 7,45 g/cm3 and the porosity was 15,19% Particle size decrease to 4.517 μm with increasing mixing speed.
Study about organic inhibitor has been performed to analyze effect of ginger extract concentration (Zingiber officinaler) to corrosion characteristic of API 5L grade steel under 3.5% NaCl and 0.1M HCl. Amount of 100 to 500 ppm inhibitor injected into each solution and electrochemistry tests were performed. Ginger extract has been prepared previously with maceration method and tested with FTIR to identify type compound in it. Tafel test result showed that corrosion rate of steel decreased in accordance with the increase of inhibitors concentration. Corrosion rate decreased to 12.13 mpy at 500 ppm inhibitor under NaCl solution, with efficiency 54.79%. While in HCl, corrosion rate showed similar trend, with corrosion rate 8.19 mpy at 500 ppm, with efficiency 81.66%. EIS result showed that impedance increased with the increase of inhibitors concentration, while FTIR result showed that ginger extract inhibitor contain 2-Methoxy-4-propylphenol which is known as antioxidant compound. According to XRD test, Fe2O3 and Fe3O4 compound were identified on steel surface. Ginger extract might worked better in acid environment since it decrease corrosion rate significantly compared to neutral solution.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.