Rungsima Yeetsorn

A Review of Thermoplastic Composites for Bipolar Plate Materials in PEM Fuel Cells

Polymer composite materials have particular properties that meet special requirements. A conductive polymer composite is positioned to play an increasingly significant role in industry and academia, specifically in the area of electrical conductivity. Even general knowledge about electrically conductive composites has been available for many years, less attention has been given in the literature to the use of conductive composites for alternative energy production. Why is the use of composite materials for energy production interesting? With a continued growth in the worldwide demand for energy, there is increasing interest in alternative technologies of energy generation such as fuel cells, for various stationary and mobile applications. In this chapter, the authors are mainly interested in a fuel cell as an energy generator, since a fuel cell is expected to play a major role in the economy of this century and for the foreseeable future. A number of factors provide the incentive for fuel cells to play a role in future energy supplies and for transportations, including climate change, oil dependency and energy security, urban air quality, and growth in distributed power generation [1]. A polymer electrolyte membrane fuel cell (PEMFC) is a good contender for portable and automotive propulsion applications because it provides high power density, solid state construction, high chemical-to-electrical energy conversion efficiency, near zero environmental emissions, low temperature operation (60 120 oC), and fast and easy startup [2,3, and 4]. The U.S. Department of Energy (DOE) has also identified the polymer electrolyte membrane fuel cells as the main candidate to replace the internal combustion engine in transportation applications [2]; however, barriers to commercialization remain. Fundamental technical challenges facing the commercialization of PEM fuel cells are manufacturing and material costs; material durability and reliability; and hydrogen storage and distribution issues [4, 5, and 6]. One of the major factors limiting fuel cell commercialization is the development of bipolar plates, which are one of PEMFC’s key components. Bipolar plate characteristic requirements are a challenge for any class of materials, and none fits the profile characteristics exactly. Therefore, research on materials, designs and fabrications of bipolar plates for PEMFC applications is a vital issue for scientists and engineers wanting to achieve the appropriate PEMFC for global commercialization. Several types of materials are

Thermoplastic Vulcanizates/Recycled Polypropylene Blend for Automotive OEM

An original equipment market (OEM) in Thailand mainly imports thermoplastic vulcanizates (TPV) from abroad that leads to a high manufacturing cost. To reduce the cost and to create value-added products from a plastic scrap, therefore, this research aim is to observe a possibility of using TPV and recycled polypropylene (rPP) blends as a raw material for OEM. The blends with various rPP loadings were successfully prepared through a traditional twin-screw extruder. Proportions between TPV and rPP were adjusted to determine the optimal flow and mechanical properties for productions of different auto parts. The blends were tested for studying rheology and mechanical properties: tensile; hardness; flexural; and creep behavior. All tests resulted in discussions about the feasibility of using TPV/rPP blends with respect to auto part specifications in real applications. Test results suggested that the TPV/rPP blends meet the requirements of specific automotive applications. Thermal property and morphological analysis were also carried out to have more understanding about changes in mechanical properties.

Preparation and properties of low density polyethylene-activated carbon composite foams

Low density polyethylene (LDPE) containing activated carbon (AC) was foamed with azodicarbonamide (ADC), an exothermic chemical foaming agent, through an extrusion process. The effects of ADC and AC contents on the cellular structure, density, void fraction, and mechanical properties of LDPE-AC composite foams were investigated. The density of composite foams decreased but the void fraction increased as the content of ADC increased due to higher gas liberation. Moreover, the large cell size was also observed in composite foams with high amount of ADC. At low AC dosages (5-10 wt%), the density of composite foams decreased with increasing the void fraction compared to the composite foam without AC because more foaming nucleation centers was induced by adding AC in the composite foam leading to more gas bubble generation. However, the addition of AC up to 15-20 wt% decreased the cell formation and the average cell size tended to decrease with increasing AC content. This attributed to AC particles that assist...

Scratch Resistance and Impact Strength of Semi Interpenetrating Networked PMMA and PU with In Situ Produced Silica

The scratch damage resistance and impact strength of PMMA sheets are necessary factors that have to be concerned by manufacturers. The aim of this work is to investigate the influences of silica (Si) from tetraethoxysilane on scratch damage resistance of the sheet surfaces for optical applications. The polymeric composites including PMMA, polyurethane (PU) and Si were produced via a bulk polymerization in a casting process. The technique creates semi-interpenetrating polymer networks (IPNs) between PMMA and PU. The percentage of IPNs and surface morphology of the composite sheets were observed. Furthermore, scratch resistance, impact strength, ultraviolet and thermal degradations of PMMA-PU-Si sheets were measured and compared with those of neat PMMA-PU sheets. The results revealed that the optimal Si amount (0.039 phr) provided 2B of the scratch resistance (2B of pencil range). This composite formula gave the highest impact values of 24.27 kJ/m2 for an Izod type and 24.94 kJ/m2 for a Charpy type. Composite sheets showed increases in ultraviolet and heat resistance by increasing the content of Si. However, the PMMA-PU-Si sheets were useable at temperature lower than 180 ⁰C.

Experimental Study on the Performance of DMFC Using Novel Composite Materials of Polypyrrole-Coated Polypropylene as BPs

Polypropylene/three-carbon-filler composite bipolar plates (BPs) of direct methanol fuel cell (DMFC) were fabricated by an injection molding. The composite materials were made of polypropylene (PP), carbon black, carbon fiber and graphite. Gas flow channel surfaces on the BPs were subsequently modified by polypyrrole (PPy) using a coating technique in order to improve surface electrical conductivity. This research is a feasibility study to use PPy-coated PP composite as BPs in a DMFC. The surface electrical resistance and performance in a fuel cell containing the composite BPs under DMFC operating conditions were evaluated against conventional graphite BPs. The surface resistance values of PPy-coated PP composites decreased around six orders of magnitude, compared with those values of PP composites. According to the performance results, PPy-coated composite BPs can be used in DMFC if the surface adhesion between a PPy layer and the BP surface was further improved.

Polymeric Material Application for The Production of Ceramic Foam Catalyst

Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85–90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by H2TPR and H2-TPD techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was 64.52 m 2 /g. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.