Key Engineering Materials VIII

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Authors: Elammaran Jayamani, Soon Kok Heng, Lee Tet Sean, Muhammad Khusairy Bin Bakri
Abstract: In this paper, chicken feather fibers (CFFs) from poultry industries were used as reinforced materials incorporated with unsaturated polyester (UP) to create composites. It is prepared by varied the percentage weight fraction of CFFs by 2wt%, 4wt%, 6wt%, 8wt%, and 10wt%. Alkaline treated potassium hydroxide (KOH) was used to alter the structure of the CFFs. From the results it showed that the tensile strength of the CFFs/UP composites was reduced. The flexural modulus has optimum results of 35.3MPa, improved by 11.86% from pure UP (31.1MPa). For flexural modulus at 2wt% and 4wt% the untreated CFFs/UP performed better performance. However, started at 6wt% onwards, chemically treated fibers surpass untreated fiber. Even though CFFs has unique characteristics properties such as hollow honeycomb structure and low density, the poor adhesion due to its smooth surface roughness and uneven distribution of fiber during mixing contributed to the low strength and flexural values. Thus, treatment caused changes in the structure of the CFFs to increase the surface roughness of the fibers, which improve adhesion.
Authors: Zhi Wang, Hai Hang Li, Jian Wang
Abstract: Dripping of polymer insulations is a different type of hazardous behaviors in wire fire, which has a potential risk of igniting adjacent combustible material and causing the dramatic growth and spread of fire in buildings, aircraft, spacecraft and nuclear power plant. To improve the fire-safety strategy, bench scale tests are conducted to study the dripping phenomenon using thin wire sample under various atmosphere pressure and electric current. The results show that the variation of flame front has a slight fluctuation during molten dripping, while the flame size (especially flame height) changes significantly. Moreover, dripping frequency (f) decreases with pressure (Ρ) due to a sufficient burning effect, but it increases with electric current (Ι) because of a stronger accumulating effect.
Authors: Sirirat Wacharawichanant, Kasana Chomphunoi, Chawisa Wisuttrakarn, Manop Phankokkruad
Abstract: This work investigated the mechanical properties and phase morphology of poly(lactic acid) (PLA)/acrylonitrile-butadiene rubber (NBR) blends and nanocomposites, which prepared by melt blending in an internal mixer. The contents of NBR were 5, 10, 15 and 20 wt% and the content of organoclay was 3 phr. The impact test showed that the impact strength of PLA/NBR blends increased with an increase of NBR content and the impact strength of the blends was more than eight times by adding NBR 10 wt% when compared with neat PLA. The tensile test showed that Young’s modulus and tensile strength of PLA/NBR blends and nanocomposites decreased after adding NBR and organoclay. While the strain at break of the NBR blends increased with increasing NBR content. This result is attributed to the rubber phase in NBR in a cause the increment of elongation and elasticity in PLA/NBR blends. The morphology of PLA/NBR blends observed the fractured surface was rougher than that of pure PLA. This observation indicates that the addition of NBR in PLA can change the brittle fracture of PLA to ductile fracture, which has an effect to the strain at break or elongation of PLA. However, the morphology of the PLA/NBR blends were also observed the phase separation of the dispersed NBR phase and PLA matrix phase, and appeared the voids in a polymer matrix. The addition of organoclay had an effect slightly on the morphology of the blends. From X-ray diffraction, results found that PLA/organoclay and PLA/NBR/organoclay nanocomposites showed the intercalated structure, which PLA chains were inserted into the interlayer of clay due to the increase of d-spacing.
Authors: Anwar Ma'ruf, Bambang Pramudono, Nita Aryanti
Abstract: Sodium lignosulfonate (SLS) is one of natural surfactant that can be modified from lignin. The utilization of natural surfactant of SLS is widely studied by researchers. This paper will study the synthesis of a natural surfactant of SLS from rice husk lignin by ultrasound assisted – sulfonation and the characteristics of SLS based on FTIR spectra. The reaction was carried out at the temperature of 60 °C and the time of 30 minutes. From the experiment can be concluded that sulfonation process with ultrasonic irradiation has advantages compared with conventional heating, i.e. lower temperature, shorter time and higher yield.
Authors: Sukantika Manatsittipan, Kamonthip Kuttiyawong, Kazuo Ito, Sunan Tiptipakorn
Abstract: In this study, the biodegradability and thermal properties the composites of polybutylene succinate (PBS) and chitosan of different molecular weights (Mn = 104,105, and 106 Da) were prepared at chitosan contents of 0-10 wt%. After 10 days of microbial degradation, the results show that the amount of holes from degradation was increased with either decreasing Mn or increasing chitosan contents. However, the size of holes was increased with increasing Mn and chitosan contents. The results from Differential Scanning Calorimeter (DSC) present that the melting temperature (Tm) of PBS was decreased with increasing chitosan contents. Moreover, there was no significant difference between Tm of the composites with different Mn of chitosan. From the TGA thermograms, the decomposition temperature at 10% weight loss (Td10) was decreased with increasing chitosan contents. Moreover, the water absorption of PBS/chitosan composites was increased with increasing Mn and content of chitosan.
Authors: Thawatchai Yaiphuak, Sujin Wanchat, Nattapon Chantarapanich
Abstract: A body armor is vital for users in combat filed. Normally, the body armor have two components: soft and hard ones. This paper proposes feasibility assessment technique to evaluate contemporary materials: Kevlar, natural spider silk, and human hair, for making soft component of the body armor. There are four criteria: technical, economic, legal, and operational feasibilities to generate the feasibility assessment matrix. The optimal material in question is human hair which has highest rank at 82%.
Authors: Xun Lai He, Jun Hui Yin, Zhen Qian Yang, Hong Wei Liu
Abstract: Carbon fiber composite material with light weight, high strength, corrosion resistance and other characteristics of its impact damage mechanism is different from the traditional metal materials. In this paper, the quasi-static compression of carbon fiber composites was carried out by using a material testing machine to analyze the damage mechanism. The Hopkinson bar technology was used to test the dynamic mechanical properties. The damage mechanism of the carbon fiber composites under dynamic compressive loading was studied. Stress - Strain relationship of composites under Quasi - static and dynamic compressive load. It is found that the main failure mode of out-of-plane direction of carbon fiber composite laminates is brittle shear failure, while the in-plane failure mode shows the properties of brittle materials.
Authors: Krittiya Singcharoen, Wansika Sirimongkol, Soontree Khuntong, Ratthapol Rangkupan
Abstract: In present study, poly (acrylonitrile-co-methyl acrylate) nanofibers were fabricated via electrospinning method and stabilized at elevated temperature in air. Electrospinning processing parameters i.e. solution concentration, solution flow rate and applied voltage were optimized. Fiber morphology and polydispersity index of fiber size was assessed from scanning electron microscope (SEM) images. Selected nanofiber was then used to study effect of stabilization time and stabilization temperature on fiber morphology, change in chemical structure and aromatization index (AI) using Fourier transform infrared spectroscopy and differential scanning calorimetry. SEM images showed drastic morphological change of stabilized fibers compared to the as spun precursor. AI value increased as stabilization time and temperature increased and reaching maximum value of 98%. This indicated high cyclization of the aromatic ring in fiber structure. Current finding is critical for carbonization process and preparation of carbon nanofibers from PAN copolymer in the future.
Authors: Lara Mae R. Lumbres, Monet Concepcion Maguyon-Detras, Maria Victoria P. Migo, Marvin U. Herrera, Ronniel D. Manalo
Abstract: This study dealt with the synthesis and characterization of thin transparent conducting films (TCF) from cellulose acetate (CA) blend and polyaniline (PANI). CA was produced from the pulp of abaca hybrid 7. CA-PANI films with different PANI loadings (0, 0.125, 0.25, 0.50, 1.0 and 2.0%) were produced using solvent casting method. Chemical transformations were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The conductivity was measured using the Four-Point Probe Test. Morphological characterization was done using Scanning Electron Microscopy (SEM). The transparency of the films was determined using UV-Vis Spectroscopy. FTIR spectra proved the embedment of PANI in the CA matrix. It was found that increasing the PANI loading increases the conductivity of the films but up to a certain limit. The highest average conductivity at 2.0264 x 10-5 S/m was observed in CA-PANI films with 0.50% PANI loading. SEM images revealed that conductivity is a function of PANI loading by forming networks. Further addition of PANI (1.0 and 2.0%) resulted to decreased conductivity due to agglomeration. Transparency, on the other hand, is negatively affected by PANI loading.

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