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Abstrak :
Produk headliner mobil dapat diperoleh dari pengembangan pengolahan busa poliuretan dan limbah kulit udang yang mengandung kitosan. Busa poliuretan yang dilapisi kitosan dengan metode pencelupan memiliki tujuan untuk memodifikasi sifat elastis menjadi kaku. Pengujian tarik menunjukkan peningkatan kekakuan, sedangkan Thermogravimetric Analysis (TGA) menunjukkan peningkatan suhu degradasi menjadi 295°C untuk tahap pertama, 309°C untuk tahap kedua, dan 372°C untuk tahap ketiga. Proses curing dapat meningkatkan jumlah hubung silang fisika berupa ikatan hidrogen, kemudian peningkatan waktu curing dapat meningkatkan jumlah hubung silang kimia berupa ikatan kovalen sehingga menyebabkan struktur menjadi homogen dan halus yang ditunjukkan oleh Field Emission Scanning Electron Microscopy (FE-SEM). Namun, suhu curing yang terlalu tinggi atau waktu curing yang terlalu lama menyebabkan ikatan hidrogen bahkan ikatan pada rantai utama terputus sehingga sifat mekanik dan termalnya menurun. Pembentukkan hubung silang fisika dibuktikan dengan Fourier Transform Infrared Spectroscopy (FTIR) yaitu peningkatan intensitas ikatan O-H, N-H, dan C=O berikatan hidrogen, sedangkan peningkatan intensitas ikatan C-N dan C-O-C mengindikasikan hubung silang kimia. Busa poliuretan yang dilapisi kitosan dengan proses curing pada 100°C selama 120 menit memiliki kekuatan tarik maksimum 5,56 kgf/cm², elongasi 7%, dan densitas 28,9 kg/m³ yang mendekati spesifikasi sifat mekanik dan fisika produk headliner pada umumnya.

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Car headliner can be obtained from the development of processing polyurethane foam and shrimp skin waste containing chitosan. Polyurethane foam coated by chitosan using immersion method has purpose of modifying elastic become stiff. Tensile testing showed the increasing of mechanical properties, while Thermogravimetric Analysis (TGA) showed the increasing of degradation temperature to 295°C for the first stage, 309°C for the second stage, and 372°C for the third stage. Curing process can add the number of physical crosslinking in form of hydrogen bonds, then the increasing of curing time can add the number of chemical crosslinking in form of covalent bonds, causing the structure become homogeneous and smooth as indicated by Field Emission Scanning Electron Microscopy (FE-SEM). However, if curing temperature is too high or curing time is too long, it will cause hydrogen bonds even main chain to be severed so that its mechanical and thermal properties decrease. The formation of physical crosslinking is evidenced by the Fourier Transform Infrared Spectroscopy (FTIR), which is increasing the intensity of O-H, N-H, and hydrogen-bonded C=O bonds, while increasing the intensity of C-N and C-O-C bonds indicates chemical crosslinking. Polyurethane foam coated by chitosan and then cured at 100°C for 120 minutes has an ultimate tensile strength of 5.56 kgf/cm², elongation of 7%, and density of 28.9 kg/m³ which is close to the specification of mechanical and physical properties of headliner in general.

Abstrak :
Ground granulated blast furnace slag (ggbs) is a waste material generated from iron production, and is one of the cementitious materials that can be used to replace part of the cement in concrete. The aim of this research was to determine the effects of the water-binder ratios and levels of ggbs in concrete, with regard to the activation energy, which is needed for predicting the concrete’s strength. A number of mixtures with different water-binder ratios (ranging from 0.30 to 0.51), ggbs levels, and curing temperatures were cast and tested at 0.5, 1, 2, 4, 8, 16, and 32 days. The activation energies were determined using the American society for testing and materials (ASTM) standard C1074, and the Freiesleben Hansen and Pedersen (FHP) method. The results of the experiment showed that the apparent activation energy was relatively independent of the water-binder ratio, and mainly affected by the ggbs level in the concrete. Higher ggbs levels in the concrete resulted in the higher apparent activation energies.