Papers by Author: Wim Nhuapeng

Abstract: Fabrication and mechanical properties of the bio-composites between water hyacinth natural fiber and paper mulberry have been investigated. The fabrication was performed using the hand lay-up technique. Untreated and treated water hyacinth fiber were used as reinforcements, in the ratio of 5%, 10%, 15%, and 20% by weight, with paper mulberry as a biomatrix. It has been found that paper mulberry reinforced with 15 % treated WH fiber showed maximum tensile strength and impact energy. The optical and scanning electron microscopic morphology of the obtained composites displayed a rougher surface and the decrease in the fiber diameter when treated with sodium hydroxide (NaOH). This improved the interlocking between the matrix and its reinforcement.

Abstract: In this research, demonstrate plasma treatment on copper substrate by Radio Frequency Plasma (RF) using a mixture of 70%C₂H₂ + 30%H₂ as the working gases. The plasma exposure time were varied from 10, 20 and 30 min under the electrical power of 50 Watts for synthesizing the diamond-like carbon (DLC) thin film on copper substrate. Thereafter, the substrates were used for synthesizing the carbon nanotubes (CNTs) via alcohol chemical vapor deposition technique (ACVD). It could be found that the plasma treatment for 10 min exhibited the small contact angle less than those of substrates treated with 20, 30 min and untreated sample which relate to the hydrophilic and affect to improve the adhesion and distribution of catalyst on substrate. The roughness of DLC film showed the different high and low level like hillock. After that, the 10 min treatment time sample was used for synthesizing the CNTs and the results found that the obtained CNTs showed good distribution on substrate.

Abstract: An experimental was investigated the condition of reinforcement of epoxy resin and hemp fiber/epoxy resin composites with carbon nanotubes (CNTs). The CNTs adding nanopowder were vibrated via the vibration milling technique for 6-48 h. Different volume percentages of CNTs were dispersed for hemp/epoxy resin composites. To compare properties of composites sample, CNTs were also added into epoxy resin for reference. Tensile strength of both specimens was tested. The significantly adding of CNTs and its dispersion in polymer matrix were investigated by scanning electron microscope (SEM). The results indicate that adding the milled CNTs can improve tensile properties of composites.

Abstract: An experimental was investigated the condition of reinforcement of hemp fiber and hemp fiber/epoxy resin composites with carbon nanotubes (CNTs).The CNTs were mixed with several liquid such as ethanol, latex, water glue and epoxy resin. These mixtures were added to hemp fiber and prepared the hemp fiber/epoxy resin composites. The mechanical properties of both fiber and composite samples were measured. It was found that the mixture of epoxy resin and CNTs with CNTs ratio of 20 vol% in hemp fiber showed the highest tensile strength of 25.43 N. and the same mixture in hemp fiber/epoxy resin composites showed the highest tensile strength of 31.82 MPa and elongation of 7.40 %.

Abstract: An experimental investigation was carried out to study the fabrication of double layers of aramid fiber/alumina/epoxy resin laminate composites using low-pressure technique. To obtain the sample with high wear resistance property, the micron size of alumina particles were added into epoxy resin using the ultrasonic processor. The physical and mechanical properties such as density, hardness, impact test, wear resistance and tensile strength of the composites samples were investigated. Furthermore, microstructures of specimens were also examined by scanning electron microscope (SEM). From the results, it was found that the mechanical properties of double layers laminate composites of aramid fiber/alumina/epoxy resin could improve by using the low-pressure technique.

Abstract: Aramid/Al2O3/epoxy resin laminated composites were fabricated using ultrasonic mixing and casting technique. This novo material could be exhibited to the ideal mechanical properties such as high tensile strength, hardness, flexural strength and lightweight which may be used to replace metal parts in vehicles. Moreover, Al2O3 powder was mixed to epoxy resin to improve the scratch resistance. To improve the bending force and interaction between Al2O3 powder phase and epoxy resin phase, the ultrasonic mixing was used for fabricating these laminate composites. The physicals and mechanical properties such as density, hardness, impact test, wear resistance and tensile strength of the composites samples were investigated. It was found that the amounts of percent by volume of the Al2O3 have affected the properties of the laminated composites. Furthermore, microstructures of specimens were also investigated by scanning electron microscope (SEM). From the results, SEM images showed good distribution and adhesion between reinforced phase and epoxy resin matrix phase.

Abstract: In this work, barium zirconium titanate (BZT) ceramics were fabricated by using a ultrasonic ball milling technique. BZT with the ratio of BaCO3:ZrO2:TiO2 was 1:0.05:0.95 was mixed in ultrasonic ball milling for 1, 3 and 4.5 hr and calcined at temperature of 1000 °C. Phase formation of BZT powder was investigated using XRD technique. Moreover, physical and electrical properties were examined. It was found that the tetragonal structure of BZT can be observed. Particle size of sample powder obtained from new milling technique is smaller than that of powder obtained from conventional mixed oxide method. Moreover, this new technique also requires the less time fabrication. Furthermore, the dielectric properties are increased with milling time and sintering temperature.

Abstract: In this research, 0-3 composites between non-lead based piezoceramic and polymer were fabricated using the suction technique. Bismuth sodium titanate (Bi0.5Na0.5TiO3:BNT) which prepared from conventional mixed oxide method was used as active phase whereas epoxy resin was used as matrix phase. The 50% volumetric fraction of BNT/epoxy resin can obtain from suction technique. The physical and piezoelectric properties of composites samples were examined. It can be found that density of composite samples were about 1.78 g/cm3. Moreover, the piezoelectric coefficient (d33) of sample was 13 pC/N. Furthermore, the microstructure of composites was determined using SEM technique.

Abstract: Carbon nanotubes (CNTs)/epoxy resin composites were prepared by using a sonication technique. Microstructure, mechanical and physical properties such as hardness, wear resistance, tensile strength and density of the composite samples were examined. The tensile strength of the 0.6 vol.% CNTs/epoxy resin composites compared with the monolithic epoxy resin increased 183%. The hardness and wear resistance were maximum at 0.8 vol.% CNTs. Moreover, SEM image of the composites indicated that there is good adhesion between CNTs and the epoxy resin.