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Academic literature on the topic 'Thick polymers'

Author: Grafiati

Published: 14 March 2023

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Journal articles on the topic "Thick polymers"

1

Marenduzzo, Davide, Alessandro Flammini, Antonio Trovato, Jayanth R. Banavar, and Amos Maritan. "Physics of thick polymers." Journal of Polymer Science Part B: Polymer Physics 43, no. 6 (2005): 650–79. http://dx.doi.org/10.1002/polb.20363.

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Gong, Xue, Guangwu Li, Cuihong Li, Jicheng Zhang, and Zhishan Bo. "Benzothiadiazole based conjugated polymers for high performance polymer solar cells." Journal of Materials Chemistry A 3, no. 40 (2015): 20195–200. http://dx.doi.org/10.1039/c5ta06065f.

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Kaufmann, Thomas, Akhilesh Verma, Van-Tan Truong, Bo Weng, Roderick Shepherd, and Christophe Fumeaux. "Efficiency of a Compact Elliptical Planar Ultra-Wideband Antenna Based on Conductive Polymers." International Journal of Antennas and Propagation 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/972696.

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A planar antenna for ultra-wideband (UWB) applications covering the 3.1–10.6 GHz range has been designed as a test bed for efficiency measurements of antennas manufactured using polymer conductors. Two types of conductive polymers, PEDOT and PPy (polypyrrole), with very different thicknesses and conductivities have been selected as conductors for the radiating elements. A comparison between measured radiation patterns of the conductive polymers and a copper reference antenna allows to estimate the conductor losses of the two types of conductive polymers. For a 158 μm thick PPy polymer, an efficiency of almost 80% can be observed over the whole UWB spectrum. For a 7 μm thick PEDOT layer, an average efficiency of 26.6% demonstrates, considering the room for improvement, the potential of this type of versatile materials as flexible printable alternative to conductive metallic paints. The paper demonstrates that, even though the PEDOT conductivity is an order of magnitude larger than that of PPy, the thicker PPy layer leads to much higher efficiency over the whole UWB frequency range. This result highlights that high efficiency can be achieved not only through high conductivity, but also through a sufficiently thick layer of conductive polymers.

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Roy, Manish Kumar, Ishwer Shivakoti, Ruben Phipon, and Ashis Sharma. "A Holistic Approach to Polymeric Material Selection for Laser Beam Machining using Methods of DEA and TOPSIS." Foundations of Computing and Decision Sciences 45, no. 4 (December 1, 2020): 339–57. http://dx.doi.org/10.2478/fcds-2020-0017.

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AbstractLaser Beam machining (LBM) nowadays finds a wide acceptance for cutting various materials and cutting of polymer sheets is no exception. Greater reliability of process coupled with superior quality of finished product makes LBM widely used for cutting polymeric materials. Earlier researchers investigated the carbon dioxide laser cutting to a few thermoplastic polymers in thickness varying from 2mm to 10mm. Here, an approach is being made for grading the suitability of polymeric materials and to answer the problem of selection for LBM cutting as per their weightages obtained by using multi-decision making (MCDM) approach. An attempt has also been made to validate the result thus obtained with the experimental results obtained by previous researchers. The analysis encompasses the use of non-parametric linear-programming method of data envelopment analysis (DEA) for process efficiency assessment combined with technique for order preference by similarity to an ideal solution (TOPSIS) for selection of polymer sheets, which is based on the closeness values. The results of this uniquely blended analysis reflect that for 3mm thick polymer sheet is polypropelene (PP) to be highly preferable over polyethylene (PE) and polycarbonate (PC). While it turns out to be that polycarbonate (PC) to be highly preferable to other two polymers for 5mm thick polymer sheets. Hence the present research analysis fits very good for the polymer sheets of 3mm thickness while it deviates a little bit for the 5mm sheets.

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Fazi, Laura, Carla Andreani, Cadia D’Ottavi, Leonardo Duranti, Pietro Morales, Enrico Preziosi, Anna Prioriello, et al. "Characterization of Conductive Carbon Nanotubes/Polymer Composites for Stretchable Sensors and Transducers." Molecules 28, no. 4 (February 13, 2023): 1764. http://dx.doi.org/10.3390/molecules28041764.

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The increasing interest in stretchable conductive composite materials, that can be versatile and suitable for wide-ranging application, has sparked a growing demand for studies of scalable fabrication techniques and specifically tailored geometries. Thanks to the combination of the conductivity and robustness of carbon nanotube (CNT) materials with the viscoelastic properties of polymer films, in particular their stretchability, “surface composites” made of a CNT on polymeric films are a promising way to obtain a low-cost, conductive, elastic, moldable, and patternable material. The use of polymers selected for specific applications, however, requires targeted studies to deeply understand the interface interactions between a CNT and the surface of such polymer films, and in particular the stability and durability of a CNT grafting onto the polymer itself. Here, we present an investigation of the interface properties for a selected group of polymer film substrates with different viscoelastic properties by means of a series of different and complementary experimental techniques. Specifically, we studied the interaction of a single-wall carbon nanotube (SWCNT) deposited on two couples of different polymeric substrates, each one chosen as representative of thermoplastic polymers (i.e., low-density polyethylene (LDPE) and polypropylene (PP)) and thermosetting elastomers (i.e., polyisoprene (PI) and polydimethylsiloxane (PDMS)), respectively. Our results demonstrate that the characteristics of the interface significantly differ for the two classes of polymers with a deeper penetration (up to about 100 μm) into the polymer bulk for the thermosetting substrates. Consequently, the resistance per unit length varies in different ranges, from 1–10 kΩ/cm for typical thermoplastic composite devices (30 μm thick and 2 mm wide) to 0.5–3 MΩ/cm for typical thermosetting elastomer devices (150 μm thick and 2 mm wide). For these reasons, the composites show the different mechanical and electrical responses, therefore suggesting different areas of application of the devices based on such materials.

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Zhang, Afang, Junji Sakamoto, and Dieter A. Schlüter. "Polymers Going Rigid, Thick, and Laterally Infinite." CHIMIA International Journal for Chemistry 62, no. 10 (October 29, 2008): 776–82. http://dx.doi.org/10.2533/chimia.2008.776.

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Glovnea, R. P., A. V. Olver, and H. A. Spikes. "Lubrication of Rough Surfaces by a Boundary Film-Forming Viscosity Modifier Additive." Journal of Tribology 127, no. 1 (January 1, 2005): 223–29. http://dx.doi.org/10.1115/1.1828069.

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In previous work it was shown that some functionalized polymers used as viscosity index improvers are able to form thick boundary lubricating films. This behavior results from adsorption of the polymer on metal surfaces to form a layer of enhanced viscosity adjacent to the surface. In the current work the behavior of one such polymer in rough surface contact conditions is studied, using both model and real rough surfaces. It is found that the polymer is able to form a thick boundary film in rough surface contact, just as it does with smooth surfaces. It is also shown that the effect of this boundary film is to significantly reduce friction in rolling-sliding, rough surface, lubricated contact.

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Reneker, Darrell H., Rajkumari Patil, Seog J. Kim, and Vladimir Tsukruk. "Scanning-probe microscopy of polymers." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 874–75. http://dx.doi.org/10.1017/s0424820100150204.

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Scanning probe microscopy techniques, particularly atomic force microscopy (AFM) and scanning tunneling microscopy (STM) are finding a rapidly growing number of applications to both synthetic and biological polymers. Segments of individual polymer molecules can often be observed with atom scale resolution. Observation of polymeric objects as large as 100 microns with nanometer resolution is possible with contemporary AFM, although features caused by the convolution of the shape of the sample and the shape of the tip must be recognized and properly interpreted. The vertical resolution of the atomic force microscope readily provides precise data about the heights of molecules, crystals, and other objects.Lamellar crystals of polyethylene are well characterized objects with many features which can be observed with scanning probe microscopes. Figure 1 shows the fold surface near a fold domain boundary of a lamellar crystal of polyethylene, as observed with an AFM. The folded chain crystal is about 15 nm thick.

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Gaikwad, Ravi, Xunchen Liu, Priyesh Dhandharia, and Thomas Thundat. "Investigation of Polymer Dendritic Growth in Composite Material using Contact Resonance Method." MRS Proceedings 1754 (2015): 61–67. http://dx.doi.org/10.1557/opl.2015.217.

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ABSTRACTA special class of polymer called dendrons which are repeatedly branched polymers linked together by a network of cascade branched monomers. A composite of these dendritic polymers with linear polymers may have unique physical and chemical properties. Using contact resonance mode of atomic force microscopy we are able to detect the viscoelastic properties of the dendritic formation of the polyethylene oxide (PEO) mixed with Polyvinylpyrrolidone (PVP). PEO is known to form nanometric crystallites due to the diffusion limited aggregation process. However, the dendritic formation in the mixture has not been reported before. The amplitude and phase of the contact resonance shows a clear dendritic growth of PEO in the composite material. The extent of the polymer crystallization can be several nanometers thick within the composite material. Additionally, the intrinsic properties of such polymers to form denrimers can be explored for fabricating polymer composites having numerous potential applications in chemical sensing, drug-delivery, energy applications and many more.

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Griehl, Stefan, Tobias Müller, and Rolf Winkler. "Thick metallization-layers on polymers through vacuum-technology." Surface and Coatings Technology 169-170 (June 2003): 24–26. http://dx.doi.org/10.1016/s0257-8972(03)00055-0.

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Dissertations / Theses on the topic "Thick polymers"

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Shindo, Nobuhiko. "Structural analysis of thick polypropylene moldings." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/10251.

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Zhao, Xiayun. "Process planning for thick-film mask projection micro stereolithography." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28097.

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Marenduzzo, Davide. "Phases of Polymers and Biopolymers." Doctoral thesis, SISSA, 2002. http://hdl.handle.net/20.500.11767/4581.

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In this thesis we develop coarse grained models aiming at understanding physical problems arising from phase transitions which occur at the single molecule level. The thesis will consist of two parts, grossly related to and motivated by the two subjects dealt with above. In the first half, we will focus on critical phenomena in stretching experiments, namely in DNA unzipping and polymer stretching in a bad solvent. In the second part, we will develop a model of thick polymers, with the goal of understanding the origin of the protein folds and the physics underlying the folding ‘transition’, as well as with the hope of shedding some light on some of the fundamental questions highlighted in this Introduction. In the first part of the thesis we will introduce a simple model of self-avoiding walks for DNA unzipping. In this way we can map out the phase diagram in the force vs. temperature plane. This reveals the present of an interesting cold unzipping transition. We then go on to study the dynamics of this coarse grained model. The main result which we will discuss is that the unzipping dynamics below the melting temperature obeys different scaling laws with respect to the opening above thermal denaturation, which is governed by temperature induced fluctuating bubbles. Motivated by this and by recent results from other theoretical groups, we move on to study the relation to DNA unzipping of the stretching of a homopolymer below the theta point. Though also in this case a cold unzipping is present in the phase diagram, this situation is richer from the theoretical point of view because the physics depends crucially on dimension: the underlying phase transition indeed is second order in two dimensions and first order in three. This is shown to be intimately linked to the failure of mean field in this phenomena, unlike for DNA unzipping. In particular, the globule unfolds via a series (hierarchy) of minima. In two dimensions they survive in the thermodynamic limit whereas if the dimension, d, is greater than 2, there is a crossover and for very long polymers the intermediate minima disappear. We deem it intriguing that an intermediate step in this minima hierarchy for polymers of finite length in the three-dimensional case is a regular mathematical helix, followed by a zig-zag structure. This is found to be general and almost independent of the interaction potential details. It suggests that a helix, one of the well-known protein secondary structure, is a natural choice for the ground state of a hydrophobic protein which has to withstand an effective pulling force. In the second part, we will follow the inverse route and ask for a minimal model which is able to account for the basic aspects of folding. By this, we mean a model which contains a suitable potential which has as its ground state a protein-like structure and which can account for the known thermodynamical properties of the folding transition. The existing potential which are able to do that[32] are usually constructed ‘ad hoc’ from knowledge of the native state. We stress that our procedure here is completely different and the model which we propose should be built up starting from minimal assumptions. Our main result is the following. If we throw away the usual view of a polymer as a sequence of hard spheres tethered together by a chain (see also Chapter 1) and substitute it with the notion of a flexible tube with a given thickness, then upon compaction our ’thick polymer’ or ’tube’ will display a rich secondary structure with protein-like helices and sheets, in sharp contrast with the degenerate and messy crumpled collapsed phase which is found with a conventional bead-and-link or bead-and-spring homopolymer model. Sheets and helices show up as the polymer gets thinner and passes from the swollen to the compact phase. In this sense the most interesting regime is a ‘twilight’ zone which consists of tubes which are at the edge of the compact phase, and we thus identify them as ‘marginally compact strucures’. Note the analogy with the result on stretching, in which the helices were in the same way the ‘last compact’ structures or the ‘first extended’ ones when the polymer is being unwinded by a force. After this property of ground states is discussed, we proceed to characterize the thermodynamics of a flexible thick polymer with attraction. The resulting phase diagram is shown to have many of the properties which are usually required from protein effective models, namely for thin polymers there is a second order collapse transition (O collapse) followed, as the temperature is lowered, by a first order transition to a semicrystalline phase where the compact phase orders forming long strands all aligned preferentially along some direction. For thicker polymers the transition to this latter phase occurs directly from the swollen phase, upon lowering T, through a first order transition resembling the folding transition of short proteins.

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Zhang, Yuemei. "UV cure kinetics of dimethacrylate thin and thick samples." W&M ScholarWorks, 2006. https://scholarworks.wm.edu/etd/1539623504.

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UV curing is using UV light as the energy source to induce the polymerization of liquid monomers and oligomers to form a solid polymer. Because UV polymerization is fast and energy-saving and a UV curable system has no VOC (volatile organic compound), this new technology has developed rapidly from thin film applications to thick sample applications. In addition, since the UV cure process can be controlled spatially and temporally, it also has an important application to make gradient materials with locally optimized properties. However, most research on UV cure is based on thin film applications, and the cure kinetics of thick samples are more complex and not well understood.;In this study, we focus on the UV cure kinetics of CD540 (ethoxylated (4) Bisphenol-A dimethacrylate) thin and thick samples (2-8 mm). A photo-bleaching initiator, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), is used in the system. UV cure kinetics are complex, especially when the sample is thick, since the light intensity is a function of depth and also a function of exposure time. In order to understand the complex cure kinetics of thick samples, we first studied the variation in the transmitted intensity and initiator concentration through the depth in thick samples. Based on the experimental measured transmitted intensity, a Matlab program was written to predict the intensity versus depth and exposure time of a thick sample. Then, the UV cure kinetics of thin samples (0.05 mm) were studied. In this part, we studied the effect of light intensity, initiator concentration, and temperature on the cure kinetics experimentally and theoretically. A model was developed based on a unimolecular termination mechanism in order to predict the cure kinetics at different conditions for thin samples. Combining the Matlab program for calculating the intensity in thick samples and the model for calculating the cure kinetics of thin samples, the cure kinetics through the depth of thick samples were predicted and compared with experimental results measured by frequency dependent dielectric sensing.;The diffusion of free radicals in a UV cure free radical cure system was studied by monitoring the cure in the dark nonirradiated region under a mask. In addition, a free radical thermal cure of an acrylic resin was characterized in order to study oxygen diffusion from the surface layers into deeper layers.

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Haria, Niraj. "Evaluation of carbon blacks and binders in polymer thick film resistors." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/12889.

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This objective of this project is to develop an understanding of the ink and its interaction with substrate of Penny & Giles controls Ltd's conductive plastic potentiometers, so as to develop alternate ink, substrate and processing methods. Conductive plastic potentiometers comprises, a track containing polymer binder and carbon black, printed on a base plastic substrate. The objectives have to take into account the performance ofthe potentiometers, which are to be improved or maintained. The first stage of the project was concerned with investigating the properties of the carbon black used in the inks, which have a major effect on the performance of the potentiometers. Ten different carbon blacks with different properties were selected. The carbon blacks properties for most of these were characterised by techniques that included transmission electron microscopy, x-ray photoelectron spectroscopy, differential scanning calorimetry, laser induced mass spectrometry and the scanning electron microscope. Inks were made with most of individual carbon blacks, and then tracks were produced on the diallyl phthalate plastic substrate. The electric resistance of these tracks was measured allowing the effect of carbon black properties on performance of the track to be studied. Various carbon black were found to provide similar performance to the Vegetabke MR842N, carbon black used currently. The next stage was the investigation of effect of binder on the performance of resistor using the same techniques as used in the first stage so that comparison could be made with the current binder. A phenolic binder was used and again showed similar properties to the DAIP binder used currently

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Henderson, Neil James. "Polymer thick film sensors for embedded smartcard biometrics and identity verification." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268936.

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Chã, Michelle Silva Vila. "Desenvolvimento de membranas de poli(éter imida) sultonada para a permeacão de gases." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2898.

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A busca por membranas com propriedades adequadas a separação de gases em escala industrial tem levado a modificação e sIntese de polImeros de engenharia, com objetivo de obter membranas com propriedades adequadas. Uma das modificaçoes que tem se apresentado promissora é a inserção de grupos sulfônicos em polImeros comerciais. Espera-se que o polImero sulfonado apresente um aumento na permeação de gases polares, em relação a gases apolares, devido a sua estrutura mais polar e flexIvel. Neste contexto, o objetivo do presente trabalho é a sIntese e caracterização de membranas de poli(éter imida) sulfonada para a permeação de gases. Um planejamento experimental foi desenvolvido, em diferentes condiçoes reacionais de temperatura, tempo e excesso de um dos reagentes (ácido acético), para a sIntese de poli(éter imida) sulfonada (SPEI). Através deste planejamento, constatou-se que as variáveis que mais influenciam o grau de sulfonação são a temperatura e o tempo. O polImero com o maior grau de sulfonação, determinado por capacidade de troca iônica (IEC= 92 mEq H+/g), foi utilizado para o preparo da membrana de SPEI, obtida pela técnica de inversão de fase por evaporação do solvente, utilizando-se clorofórmio como solvente. Este filme foi caracterizado a partir das seguintes análises: espectroscopia de infravermelho (FTIR), calorimetria diferencial de varredura (DSC), análise termogravimétrica (TGA) e microscopia eletrônica de varredura (MEV), a fim de avaliar a influência da inserção do grupo sulfônico na matriz polimérica. O espectro de infravermelho de SPEI apresentou bandas relacionadas as vibraçoes assimétricas em 1240 cm-1 (ligação O=S=O), ligação simétrica em 1171 cm-1 (O=S=O) e ligação S-O entre 1010-1024 cm-1. Isto indica a presença de grupos sulfônicos. A análise de DSC foi realizada entre 150-250C. Nesta faixa, não foram observadas alteraçoes na temperatura de transição vItrea (Tg) do polImero modificado (217C). Acredita-se que a decomposição do grupo sulfona aconteça antes da temperatura atingir o Tg do polImero. Esta suposição é confirmada na análise de TGA. As imagens de MEV mostraram que foram obtidos filmes livres de poros e defeitos. A membrana da SPEI foi utilizada no ensaio de permeaçao dos gases 02, N2 e C02, a fim de determinar a permeabilidade e seletividade da membrana. As permeabilidades encontradas para o gas oxigênio foram de 0,76 barrer para a PEI e 0,46 barrer para a SPEI. A seletividade do dióxido de carbono em relaçao ao oxigênio aumentou de 3,5, na membrana de PEI, para 4,83, na membrana de SPEI. Em relaçao ao nitrogênio, as permeabilidades medidas foram 0,064 barrer e 0,043 barrer, para a PEI e para a SPEI, respectivamente, enquanto a seletividade em relaçao ao C02 aumentou de 41,1 para 55,5. Estes resultados indicam que o efeito de sorçao predominou devido ao aumento das interaçöes moleculares, reduzindo assim o volume livre, o que tornou a membrana sulfonada mais compacta, com permeabilidade menor e maior seletividade. Estes resultados corroboram com a premissa de que a sulfonaçao é um processo promissor para o desenvolvimento de membranas mais eficientes.
The search for membranes with suitable properties for gas separation in industrial scale has led to the modification and synthesis of engineering polymers with the purpose of obtaining membranes with superior properties. 0ne of the modifications that have been considered promising is the insertion of sulfonic groups in commercial polymers. Due to its structure more polar and flexible, it is expected that the sulfonated polymer present an increase in polar gas permeation in relation to nonpolar gases. In this context, the objective of this work is the synthesis and characterization of membranes of poly (ether imide) sulfonated for the permeation of gases. An experimental design was developed in different reaction conditions of temperature, time and an excess of one of the reagents (acetic acid), for the synthesis of poly (ether imide) sulfonated, SPEI. Through this planning, it was found that the variables that most influenced the degree of sulfonation are temperature and time. The polymer with the highest degree of sulfonation, by ion exchange capacity (IEC = 92 mEq H+ I g), was used to prepare SPEI membrane obtained by the technique of solvent evaporation, using chloroform. This film was characterized from the following analysis: infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) to evaluate the influence of insertion of the sulfonic group in the polymer matrix. The infrared spectrum showed bands of SPEI related to asymmetric vibrations at 1240cm- 1 (S = 0 = 0), in symmetric stretch at 1171 cm-1 (0 = S = 0) and S0 stretch between 1010-1024cm-1. This indicates the presence of sulfonic groups. The DSC analysis was carried out between 150-250C. In this range, there are no significant changes in glass transition temperature of the modified polymer (217C). It is believed that the decomposition of the sulfone group occurs before the temperature reaches the Tg of the polymer. This assumption is confirmed in the TGA analysis. The images of SEM showed that films were obtained free of pores and defects. The membrane SPEI obtained by the technique of solvent evaporation, was used for testing permeation of gases 02, N2 and C02 in order to determine the permeability and selectivity of the membrane. The permeabilities found for oxygen were 0.76 barrer for PEI and 0.46 barrer for SPEI. The selectivity of carbon dioxide relative to oxygen increased from 3.5 to 4.83. Regarding nitrogen, the permeability measurements were 0.064 barrer and 0.043 barrer for the PEI and the SPEI, respectively, while the selectivity relative to C02 increased from 41.1 to 55.5. These results indicate that the predominant effect of sorption due to increased molecular interactions, thus reducing the free volume, made the membrane sulfonated more compact with lower permeability and higher selectivity. These results agree with the premise that the sulfonation is a promising process for the development of more efficient membranes.

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Kenning, Nicole Lynn. "Spatial and temporal evolution of the photoinitiation rate in thick polymer systems." Diss., University of Iowa, 2006. http://ir.uiowa.edu/etd/76.

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Seymour, Paul Jonathan. "Preparation and characterisation of colloidal particles with a thick stabilising polymer layer." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274601.

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Pavuluri, Sumanth Kumar. "High efficiency planar microwave antennas assembled using millimetre thick micromachine polymer structures." Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2452.

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Communication systems at microwave and millimetre wave regimes require compact broadband high gain antenna devices for a variety of applications, ranging from simple telemetry antennas to sophisticated radar systems. High performance can usually be achieved by fabricating the antenna device onto a substrate with low dielectric constant or recently through micromachining techniques. This thesis presents the design, fabrication, assembly and characterisation of microstrip and CPW fed micromachined aperture coupled single and stacked patch antenna devices. It was found that the micromachining approach can be employed to achieve a low dielectric constant region under the patch which results in suppression of surface waves and hence increasing radiation efficiency and bandwidth. A micromachining method that employs photolithography and metal deposition techniques was developed to produce high efficiency antenna devices. The method is compatible with integration of CMOS chips and filters onto a common substrate. Micromachined polymer rims (SU8 photoresist) was used to create millimetre thick air gaps between the patch and the substrate. The effect of the substrate materials and the dimensions of the SU8 polymer rims on the performance of the antenna devices were studied by numerical simulation using Ansoft HFSS electromagnetic field simulation package. The antenna structures were fabricated in layers and assembled by bonding the micromachined polymer spacers together. Low cost materials like SU8, polyimide and liquid crystal polymer films were used for fabrication and assembly of the antenna devices. A perfect patch antenna device is introduced by replacing the substrate of a conventional patch antenna device with air in order to compare with the micromachined antenna devices. The best antenna parameters for a perfect patch antenna device with air as a substrate medium are ~20% for bandwidth and 9.75 dBi for antenna gain with a radiation efficiency of 99.8%. In comparison, the best antenna gain for the simple micromachined patch antenna device was determined to be ~8.6 dBi. The bandwidth was ~20 % for a microstrip fed device with a single patch; it was ~40 % for stacked patch devices. The best bandwidth and gain of 6.58 GHz (50.5%) and 11.2 dBi were obtained for a micromachined sub-array antenna device. The simulation results show that the efficiency of the antenna devices is above 95 %. Finally, a novel high gain planar antenna using a frequency selective surface (FSS) was studied for operation at ~60 GHz frequency. The simulation results show that the novel antenna device has a substantial directivity of around 25 dBi that is required for the emerging WLAN communications at the 60 GHz frequency band.

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Books on the topic "Thick polymers"

1

Gilleo, Ken. Polymer thick film. New York: Van Nostrand Reinhold, 1996.

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Bessey, David T. Radiation effects on polymer thick film resistors. 1988.

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Polymer Thick Film: Today's emerging technology for a clean environment tomorrow (Electrical Engineering). Springer, 1995.

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How to Do Fimo If You Think You Can't: 25 Easy to Make Projects for Beginners. Hot Off the Press, 1996.

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Book chapters on the topic "Thick polymers"

1

Gooch, Jan W. "Thick." In Encyclopedic Dictionary of Polymers, 748. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11819.

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Gooch, Jan W. "Thick Filling." In Encyclopedic Dictionary of Polymers, 748. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11823.

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Gooch, Jan W. "Thick-and-Thin Yarn." In Encyclopedic Dictionary of Polymers, 748. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11820.

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Podlubnaya, Zoya A. "Composition and Structural Dynamics of Vertebrate Striated Muscle Thick Filaments." In Structure and Dynamics of Confined Polymers, 295–309. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0401-5_18.

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Eliasson, Veronica, and Rodrigo Chavez. "Dynamic Response of Polymers Subjected to Underwater Shock Loading or Direct Impact." In Advances in Thick Section Composite and Sandwich Structures, 145–67. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-31065-3_5.

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Bolognesi, A., M. Catellani, S. Destri, W. Porzio, C. Taliani, R. Zamboni, and S. Brückner. "Structural Characterization of Thiophene-Based Monomers, Polymers, and Oligomers as Powders, Thick, and Thin Films." In Lower-Dimensional Systems and Molecular Electronics, 411–14. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4899-2088-1_47.

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Császár, Csaba. "Polymer Thick-Film Pressure Sensor." In Multichip Modules with Integrated Sensors, 315–19. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0323-4_33.

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Hoo Fatt, Michelle S., Chong Zhong, and Xiaolong Tong. "On Characterizing Multiaxial Polymer Foam Properties in Sandwich Structures." In Advances in Thick Section Composite and Sandwich Structures, 387–405. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-31065-3_13.

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Adams, Mark R., KiRyong Ha, Jenifer Marchesi, Jiyue Yang, and Andrew Garton. "Surface Analysis of Thick Polymer Films by Infrared Spectroscopy." In Advances in Chemistry, 333–49. Washington, DC: American Chemical Society, 1993. http://dx.doi.org/10.1021/ba-1993-0236.ch012.

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Fortunko, C. M., and D. W. Fitting. "Apropriate Ultrasonic System Components for NDE of Thick Polymer-Composites." In Review of Progress in Quantitative Nondestructive Evaluation, 2105–12. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3742-7_126.

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Conference papers on the topic "Thick polymers"

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Che, H., P. Vo, and S. Yue. "Metallization of Various Polymers by Cold Spray." In ITSC2017, edited by A. Agarwal, G. Bolelli, A. Concustell, Y. C. Lau, A. McDonald, F. L. Toma, E. Turunen, and C. A. Widener. DVS Media GmbH, 2017. http://dx.doi.org/10.31399/asm.cp.itsc2017p0098.

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Abstract Previous results at McGill University have shown that metallic coatings can be successfully cold sprayed onto polymeric substrates. This paper studies the cold sprayability of various metal powders on different polymeric substrates. Five different substrates were used, including carbon fibre reinforced polymer (CFRP), acrylonitrile butadiene styrene (ABS), polyether ether ketone (PEEK), polyethylenimine (PEI); mild steel was also used as a bench mark substrate. The CFRP used in this work has a thermosetting matrix, and the ABS, PEEK, and PEI are all thermoplastic polymers, with different glass transition temperatures as well as a number of distinct mechanical properties. Three metal powders, tin, copper and iron, were cold sprayed with both a low-pressure system and a high-pressure system at various conditions. In general, cold spray on the thermoplastic polymers rendered more positive results than the thermosetting polymers, due to the local thermal softening mechanism in the thermoplastics. Thick copper coatings were successfully deposited on PEEK and PEI.

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Jones, Brian, Ying Bo Zhang, R. V. Athalye, Lie Zhang, C. H. Wang, J. M. Takacs, and Stephen Ducharme. "Improved photorefractive polymers." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.my3.

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We report the performance of photorefractive polymers that have improved response time and phase stability. The polymers studied consist of a host polymer, an attached nonlinear optical moiety, plus a hole transport agent, similar to those previously reported.1 One such composition consists of the host polymer Bisphenol-A with the moiety 4′-amino-4′-nitrostilbene and the hole transport agent diethyl-aminobenzaldehyde-diphenyl hydrazone. Samples 145 μm thick exhibit a diffraction efficiency of 0.01% and an exponential response time constant of 0.1 s with an applied field of 90 kV/cm at a wavelength of 650 nm, 1.6 μm grating spacing, and an intensity of 0.3 W/cm2. These results represent a 1,000-fold improvement in sensitivity (at comparable absorbance) over the results reported in Ref. 1. There is no observable decrease in the photorefractive or photoconductive sensitivities of a sample stored 20 days at room temperature. This is also the first report, to our knowledge, of photorefractivity in a non-cross-linking electro-optic polymer. We also discuss the influence of the polymer composition, polymer processing, and experimental conditions on photorefractive performance and comparison with direct measurements of electro-optic and photorefractive response.

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Ducharme, S., J. C. Scott, R. J. Twieg, and W. E. Moerner. "Demonstration of Photorefractivity in Organic Polymers." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.pdp28.

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Polymeric nonlinear optical materials offer a number of potential advantages over inorganic materials, particularly low cost of material, low dc dielectric constant, ease of fabrication, and compatibility with integrated optics. We report here for the first time firm evidence of photorefractivity in a nonlinear optical polymer. Photorefraction (at 647.1 nm) was established by a combination of hologram erasability, correlation with photoconductivity and electro-optic response, and enhancement by external fields in numerous samples (178 to 533 µm thick) of the polymers (BisA-NPDA)1 or (NA-APNA)2 mixed with hole transport agents such as p-diethylaminobenzaldehyde-diphenyl hydrazone (DEH). Diffraction efficiencies up to 0.1% (NA-APNA) and 0.06% (BisA-NPDA) were observed at bias fields of 84 kV/cm and 126 kV/cm, respectively. The calculated space-charge field in one sample of the BisA-NPDA mixture was 47 kV/cm (the largest yet reported in any photorefractive material) at 126 kV/cm and a grating spacing of 0.2 µm; the estimated photorefractive trap density was 6 × 1015cm−3.

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Moerner, W. E., J. C. Scott, S. Ducharme, P. Walsh, D. M. Burland, G. C. Bjorklund, M. Lux, and R. J. Twieg. "Photorefractivity in doped nonlinear polymers." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.mj3.

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Photorefractive polymer materials offer a number of potential advantages over inorganic materials, particularly low cost of material, low dc dielectric constant, ease of fabrication, and compatibility with integrated optics. Our first reports of photorefractivity in an organic polymer1 established the presence of the effect by a combination of hologram erasability, correlation with photoconductivity and electro-optic response, and enhancement by external fields in numerous samples (≃350 μm thick) of the epoxy polymers bisA-NPDA (bisphenol-A-diglycidylether-nitrophenylenediamine) or NA-APNA (N,N-(diglycidyl)-4-nitroaniline-N-(2-aminophenyl)-4-nitroaniline) mixed with three different hole transport agents similar in structure to p-diethylaminobenzaldehyde-diphenyl hydrazone (DEH). Diffraction efficiencies up to 0.1% (NA-APNA) and 0.06% (bisA-NPDA) were observed at bias fields of 84 kV/cm and 126 kV/cm, respectively. Using standard Kukhtarev theory to model the field dependence of the results, we find bestfit values for the space-charge field in the bisA-NPDA/DEH mixture of 26 kV/cm at an applied field of 126 kV/cm and a grating spacing of 1.6 μm; the estimated photorefractive trap density was 1.9 × 1015 cm-3. The steady-state diffraction efficiencies show a polarization anisotropy in agreement with the photorefractive interpretation. Recent experiments to fully characterize the photoconductivity and to extend this work to other materials systems are summarized.

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Nassr, Nooshin, Zahed Siddique, and Jon R. Keegan. "Permeability Characterize of Polymeric Materials at High-Temperature and High-Pressure." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67174.

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A new experimental set-up has been built to characterize the permeation of polymeric materials. The permeation of Helium through the variety of polymers under different pressure and temperature conditions was investigated. In this study, the gas permeation measurement has been performed by a high temp/high pressure gas permeation cell. Constant volume (variable pressure) procedure was considered to design this gas permeation cell. In designing the permeation cell, special consideration has been made to build a permeation cell appropriate for testing polymer samples in high pressure (up to 1200 psi) and high temperature (up to 100 °C) conditions. The permeation cell consists of two gas chambers; the high pressure side and the low pressure side. A modular plugin has been designed to place inside the gas chambers, and make the design adjustable for testing polymers with different thicknesses. Pressure change in the lower side of the set-up was measured by sensitive pressure transducer. Downstream pressure side will be used in the calculation of gas flux and gas permeation coefficient of polymers, along with differential pressure applied to polymer sample and test conditions as temperature. The results of permeability measurements for thick polymer samples at different pressure and temperature showed that the effects of increasing temperature on gas permeation are prominent compared to effect of high pressure condition.

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Yoshizawa, Masayuki, Makoto Taiji, and Takayoshi Kobayashi. "Dynamics of Excitons in Conjugated Polymers." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/up.1990.wa4.

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Optical and electrical properties of conjugated polymers have been extensively investigated because 'of their large and fast optical nonlinearities and their role as model compounds for quasi-one dimensional semiconductors. In the present study, time evolution in polydiacetylenes (PDA-3BCMU and PDA-4BCMU) and poly(3-methy1thiophene) (P3MT) was investigated by femtosecond absorption spectroscopy and picosecond luminescence spectroscopy [1]-[3]. The samples of PDA-3BCMU and PDA-4BCMU (butoxycarbonylmethylurethane) are cast films of about 100 nm thickness on glass substrates. About 1 μm-thick films of P3MT was prepared by electrochemical polymerization on glass substrates.

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Giorgini, Loris, Laura Mazzocchetti, Giangiacomo Minak, and Enrico Dolcini. "Investigation of a carbon fiber/epoxy prepreg curing behavior for thick composite materials production: An industrial case-study." In 6TH INTERNATIONAL CONFERENCE ON TIMES OF POLYMERS (TOP) AND COMPOSITES. AIP, 2012. http://dx.doi.org/10.1063/1.4738439.

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Ruszkiewicz, Brandt J., Gene Simpson, and Eric Breidenbaugh. "Comparison of Commercially Available Thread Forming Profiles on Flow Drill Joining of 6061-T6 Aluminum to Thermoset Carbon Fiber Reinforced Composite." In ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2927.

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Abstract Flow Drill Screws are self-piercing, self-tapping screws used for single sided joining of light metals, such as aluminum. This technology has been adopted by many automotive OEMs for use in metals. Thread forming profiles exist for material stackups that are made of entirely metals and entirely polymers/composites. This research evaluated the effectiveness of these thread profiles in dissimilar metal-on-composite stackups. Thread profiles designed for use in polymers/composites and aluminum were compared with a traditional machine screw thread profile for flow drill joining of 1mm and 2mm thick 6061-T6 aluminum to 3mm thick thermoset carbon fiber reinforced polymer. The three thread profiles were manufactured as M5x25mm flow drill screws in their commercially available configurations and materials. Two parameter sets from the FDS equipment manufacturer were evaluated, the first designed for use with the polymer thread forming profile, the second designed for use with the aluminum thread forming profile. The thread profiles were evaluated based on outputs of process time, peak torque, and lap shear strength. The polymer thread profile had shorter process times than the other 2 profiles but caused more damage to itself and its mating material. All 3 thread profiles exhibited greater shear strength when aluminum was used as the lower sheet material.

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Yao, Donggang, Allen Y. Yi, Lei Li, and Pratapkumar Nagarajan. "Two-Station Embossing Process for Rapid Fabrication of Polymer Microstructures." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80482.

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The hot embossing technique is becoming an increasingly important alternative to silicon-and glass-based microfabrication technologies. The advantage of hot embossing can be mainly attributed to the versatile properties and mass production capability of polymeric materials. However, because of the use of a large mass in thermal cycling, hot embossing is subject to substantially longer cycle times than those in traditional thermoplastic molding processes.1 The longer dwell time at elevated temperatures could further result in degradation of the embossing polymer, especially for thermally sensitive polymers. The problem exacerbates when thick polymer substrates are used. To address this problem, rapid thermal cycling of the tool is needed. One method for rapid thermal cycling is to employ a low-thermal-mass multilayer mold with electrical heating elements installed right beneath the mold surface.2 This method, however, is complex in nature and may be prone to problems caused by mismatching of thermal and mechanical properties between different layers.

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Hide, F., M. A. Diaz-Garcia, M. McGehee, B. J. Schwartz, and A. J. Heeger. "Conjugated Polymers as Materials for Thin Film Solid State Lasers." In Organic Thin Films for Photonic Applications. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/otfa.1997.wd.1.

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Optically pumped gain narrowing and lasing have been demonstrated in submicron thick films, neat and undiluted, of photoluminescent conjugated polymers. The dramatic collapse of the emission line width occurs at very low pump energy thresholds (~10 μJ/cm2). Gain narrowing is found in over a dozen different conjugated polymers representing a variety of molecular structures, including poly(p-phenylenevinylene), poly(p-phenylene) and polyfluorene derivatives; the emission wavelengths in these materials span the visible spectrum. The short gain lengths in conjugated polymers are attributed to the high density of chromophores, the large density of states associated with the interband (π-π*) transition in quasi-one-dimensional systems, and the Stokes shift which minimizes self-absorption and allows optical pumping to the excited state without simultaneously stimulating emission (thereby yielding population inversion). Lasing and gain narrowing are compared for a soluble poly(phenylene vinylene) derivative using two different resonant structures: planar waveguides and microcavities. In both cases, the gain narrowing threshold is at 0.05 - 0.1 μJ per 10 ns pulse focused to approximately 1.5 mm. Single mode microcavity lasers are obtained when a cavity resonance occurs at the wavelength where the gain of the polymer is a maximum. Low threshold lasing (threshold more than an order of magnitude below that observed in planar waveguides and microcavities) has also been demonstrated using distributed feedback in a planar chip film configuration.

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Reports on the topic "Thick polymers"

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Selwood, R. K., G. Rosenberger, and A. Zelinski. The Replacement of Precious Metal Thick Film Inks Using Conductive Polymer Technology. Fort Belvoir, VA: Defense Technical Information Center, February 1985. http://dx.doi.org/10.21236/ada152002.

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