Papers by Keyword: Polymer

Abstract: Effect of addition different polymers and fillers with electron beam irradiation on changes of physical, electrical and flammability properties of low density polyethylene (LDPE) / trimethylol propane trimethylacrylate (TMPTMA) / Irganox/ zinc borate (ZB) have been investigated. Results of measured gel content (GC), tensile strength (TS), elongation at break (EL), hot set (HS) tests, melt index (MFI), dielectric strength (DS), volume resistivity (VR), flammability and limiting oxygen index (LOI) have confirmed positive effects of adding maleic anhydride grafted LDPE (LDPEgMAH), ethylene vinyl acetate (EVA) and CS whereas effect of ATH to blends drastically had negative effects on improvement of physical properties of blends. Meanwhile, presence of TMPTMA and enhancing irradiation could improve properties seriously. Keywords Halogen free; polymers; irradiation; wires and cables

Abstract: A traditional III-V GaAs/AlGaAs based semiconductor solar cell heterojunction structure, i.e. n-GaAs/n-AlGaAs/n-GaAs/i-GaAs/p-GaAs is used in this study to investigate the surface polymer passivation on this kind of solar cell. For GaAs/AlGaAs solar cell, the top n-GaAs/n-AlGaAs structure is responsible for the selective etching stop layer. The selective etched surface barriers associated with polymer gratings with different aspect ratios, i.e. grating period (gp) to depth (d), are produced on solar cell surface by using the photolithography and Micro Electro Mechanical Systems (MEMS) techniques. A reflective-type diffraction optical grating is fabricated on the surface of the solar cell to redirect the incident light reflected from the solar cell back onto the solar cell surface. The experimental results show that the addition of the surface optical gratings reduce the light reflectivity value as high as 25%. From inspection of surface reflectivity , the average reflectivity is found to be decreased from 12.1% down to 7.9 %.

Abstract: This paper presents results from a series of experiments in which two combinations of polymer-dye film were exposed to ionizing radiation (electron beam). These experiments were performed for the purpose of investigating the possibility of polyethylene (PE) and polyvinyl chloride (PVC) with and without the addition of malachite green (MG) dye for radiation indication in the form of colour transition. MG dye was also inspected whether it has experienced the photodarkening from the exposure to ionizing radiation. The experiments were carried out using samples in the form of film. From this study, it was proven that the polymers and dye do not work alone to give the change. Halogen-containing polymer was found positive in stimulating the acid-sensitive dye for the transition of colour. The colour transition of the combination of PVC/MG without pH adjustment was consistently increasing with irradiation level. The transition is observed even at 100 kGy of the radiation exposure. Samples with the addition of basic solution have a rapid change in terms of colour but the limit of sensitivity was decreased to only 20 kGy of radiation exposure.

Abstract: The effluent of wastewater treatment plants (WWTPs) is an important source of priority substances and is, therefore, one of the bottlenecks in achieving the European Water Framework Directive (WFD) objectives. At various locations in the Netherlands, standard for priority substances are exceeded. The current concern regarding the cost and treatment method of these micropollutants in receiving waters may call for new approaches in wastewater treatment. In this study, a new treatment alternative is developed to remove micropollutant and wastewater parameter effectively and in a more cost effective way. A potential solution is the used of clay coupled with biodegradable polymer flocculants. Clay is naturally abundant and relatively inexpensive compared to currently conventional used adsorbent which can also act as coagulants. Experimental studies were carried out with four different nanoclay to select the best nanoclay for further optimisation. The atrazine removal percentage archived is in the range of 10-99% based on the nanoclay concentration of 0.01-50 g/L. Optimisation of best nanoclay performer leads towards atrazine reduction of >99% with dosage of 0.1 g/L. The best and underperformed nanoclay then tested in other experiments with the addition of cationic starch flocculants. In this experiment, the addition of polymer increased the atrazine removal for the underperformer nanoclay to 46% with only 0.01 g/L clay dosages. This new approach in dealing with both micropollutant and wastewater parameter is promising and might help in reducing the compound concentration and the operational cost. However, further analysis and optimisation is required before any conclusion can be made.

Abstract: An introduced article deals with the possibility of re-use of waste materials in production. The observed properties are the tensile properties of newly created material, namely yield stress, stress at break. Changes in strength characteristics and suitability of replacing the pure, primary material with the secondary, waste plastics were determined by material tests. The report gives a cross-section in methodology of tests performing, results processing and implementation into practice.

Abstract: The effect of multi-wall carbon nanotubes content on physico-mechanical properties of glass microspheres-epoxy resin syntactic foam was evaluated experimentally. Syntactic foam with high volume fraction of microspheres (70 vol%) was prepared and modified by 1 to 5 vol% of multi-wall carbon nanotubes. The compressive, flexural and impact strength tests were conducted, the load-displacement curves were captured. The quality of dispersion of nanoparticles was evaluated in relation to the mixing procedure using scanning electron microscope observation.

Abstract: Recently, organic-inorganic hybrid nanocomposite materials have been of great interest for their extraordinary performances due to the combination of the advantageous properties of polymers and the size dependent properties of nanocrystals (NCs). Interaction between the polymer matrix and nanocrystalline fillers produces wonderful features, viz. thermal, magnetic, mechanical, electrical and optical properties to these materials. Modern applications require a new design of responsive functional coatings which is capable of changing their properties in a controlled way. However, the synthesis of II-VI nanoparticles into the polymer matrix of its nanocomposites with adjustable sizes and protected from photo-oxidation is a big challenge to the scientific community. It is difficult to synthesize the highly enhanced luminescence in polymers and its semiconductor nanocomposite systems. Luminescence from the polymer embedded II-VI nanoparticles is greatly enhanced and better stability can be achieved from the composite compared to bulk materials. The formation of nanocomposites can be confirmed by photoluminescence (PL) spectroscopy. It is an important technique for determining the optical gap, purity, crystalline quality defects and analysis of the quantum confinement in these nanocomposite materials. In this paper, we have reviewed the present status of II-VI polymer nanocomposites from the photoluminescence studies point of view. We have also shown the results of the PL of these nanocomposite materials and the results will be compared with the reported literature by other groups.Contents of Paper

Abstract: In this paper, microscopic method, transmission technique and attenuated total reflection method of infrared spectroscopy and differential scanning calorimetry were investigated for analyzing the component of inner and outer layer of sheath-core polymer fiber. Results showed that transmission technique and attenuated total reflection method of infrared spectroscopy was a quick and accurate method for identification of sheath-core fiber of fiber.

Abstract: This paper tested the pore structure, capillary water absorption and impermeability of cement mortars modified with three polymers respectively, establishing the relationship between the pore structure and waterproof performance. The results show that with the polymer dosage growing, especially as the polymer/cement ratio (m_p/m_c) increases from 0% to 5%, the reduction in the capillary water absorption and the penetration depth of water into mortar is significant. In the m_p/m_c range of 0%~20% the open porosity presents a gradual decrease trend. The capillary water absorption and the penetration depth of water into mortar show linear growth and exponential growth respectively with the open porosity increasing.

Abstract: Forming three groups concrete of different gelled material systems, the effecting of HPI hydrophobic compound hole plug on concrete compressive strength, chloride ion permeability resistance and water absorption performance were studied taking CALTITE and 3CC for example. Studies have shown that this kind of polymer can reduce compressive strength, but can improve chloride ion permeability resistance and hydrophobic property of concrete.