Thermal Characterizations of HPMC/PVA Impregnated with CNC Electrospun Nanofibers

Interest in the nanotechnology invention has been increased among the researcher and industries which lead to many investigations and studies to develop a product with better performance. In this research, hydroxypropyl methylcellulose (HPMC) and poly (vinyl) alcohol (PVA) nanofiber with the ratio 1:1 and the concentration of 5 wt% and 7 wt%, respectively, were successfully fabricated by using electrospinning technique. The HPMC/ PVA was then blended with the different concentration of cellulose nanocrystal (CNC) at 2 wt%, 4 wt%, 6 wt% and 8 wt%. The SEM results of HPMC/PVA/CNC nanofibers shown random orientation fibers with average diameters of 62.28 nm - 252.80 nm. The TGA results showed three major weight loss that prove the decomposotion of HPMC/PVA/CNC was occured with three maximum temperature peaks around 69 °C, 290 °C and 392 °C. As for DSC, the peak intensity of the Tg in the electrospun nanofiber are decreasing as the concentration of CNCs increased might be due to the interfering of the CNC with the crystallization of the polymer causing mobility of the amorphous regions to be higher. Therefore, the study on the thermal properties of HPMC/PVA incorporated with CNCs nanofibers could be a reference for various potential applications.

Characterisation of Silicon Carbide from Dark Red Meranti Wood

Porous biomorphic silicon carbide is a promising ceramic materials for used in wide variety of applications especially in filtration and separation. Wood derived silicon carbide retains the heterogeneous structure of initial wood. Silicon carbide ceramic was derived from Dark Red Meranti wood precursor in this study. The derivation process was prepared by reaction between liquid silicon and carbon preform. The carbon preform was obtained via pyrolysis process at 850 °C in Argon gas flow atmosphere. This process was followed by Si infiltration at 1500 °C for different holding hours. The density was determined using Archimedes method. SEM was performed to observe their microstructures while the compositions and phase analysis were analysed by EDX and XRD respectively. Thermogravimetric analysis showed that a major weight loss of about 60% of carbon perform due to the decomposition of cellulose and lignin.XRD results revealed the presence of SiC and excess of silicon. It was found that conversion efficiency of carbon into SiC has been improved when the holding time was increased.

Thermal Property of Eutectic Molten Salts by Using Thermogravimetric Analyzer (TGA)

The thermal property of new composition of eutectic molten salt was investigated to obtain low melting point and better stability at temperature of 500°C as heat transfer fluid in solar thermal energy system. The NaCl used was purified from seawater. The eutectic molten salts were prepared in ten different weight ratios and experiments were carried out using nitrogen as inert gas with heating of 10°C/min to the temperature from 25°C to 500°C. Experimental results indicated that all mixtures exhibited low melting point (<163°C) and high stability. The thermal degradation of LiNO3, NaNO3, KNO3 and NaCl exhibit in the DTG profiles respectively. From the present study it can be concluded that major weight loss of the system is due to the dissociation of lithium nitrate to lithium oxides.