Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"polymer additives"”.
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Applications of supercritical fluids to the extraction and analysis of oligomers and polymer additives
… area of applications has been in the field of polymeric materials. Since polymers are not discrete molecules, but, rather broad distributions of very similar compounds (oligomers), they can pose interesting challenges for the separation chemist. SFs are uniquely suited to meet these challenges. …
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Supramolecular polymer additives to improve the crystallization behavior and optical properties of polybutylene terephthalate and polyamides
The use of additives to enhance the processability and end properties is one of the main measures to enlarge the property profile of commercial thermoplastic polymers. The physico chemical properties of semi crystalline polymers depend to a large extend on the crystal structure and spherulite size, …
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The effect of polymer additives on the hydrodynamic stability and nonlinear evolution of thin liquid films
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1996.
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Drag Reduction by Polymeric Additive Solutions
Historically, the addition of polymers to turbulent flows of Newtonian fluids has been known to effectively reduce turbulent friction drag by up to 80 %. Conducted in the Hydrodynamics Laboratory in Virginia Tech, this research presents a comprehensive analysis into drag reducing effects through …
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Effect of formulation on the movement of atrazine, alachlor, and metribuzin in a coarse-textured soil
… of controlled release formulations and acrylic polymer additives on herbicide movement in a Plainfield sand was evaluated in field and soil column experiments. Controlled release formulations included starch-based encapsulations of the three herbicides and a commercially available …
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Quantitative Analysis of Additives in Low Density Polyethylene Using On-line Supercritical Fluid Extraction /Supercritical Fluid Chromatography
Polymer additives exemplify many classes of compounds which possess a wide variety of chemical (i.e., phenols, amides, esters) and physical (i.e., volatility, solubility) properties. They are incorporated into polyolefins and other such polymeric materials for a number reasons: (a) to prevent …
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Surface textures and non-Newtonian fluids for decreased friction in full film lubrication
… in the lubrication industry has been to add polymer additives to base oils in order to increase their effectiveness as lubricants. These polymer additives, however, cause the oil to become a Non-Newtonian viscoelastic lubricant. The final portion of this work presents the first experimental …
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Investigation of interfacial bonding in banana fiber-reinforced composites : ascribing global economic value to unique renewable resources in developing countries.
… fibers have increased in popularity in the polymer composite industry, due to the steady rise of consumer pressure for biodegradable and environmentally-friendly products. However, the organic nature of these natural fibers causes poor interfacial bonding with the majority of thermoplastic …
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Extraction of Additives from Polystyrene and Subsequent Analysis
The extraction of fifteen (15) polymer additives with supercritical carbon dioxide which are used as antioxidants, uv stabilizers, process lubes, flame retardants and antistats from eight formulations of polystyrene is demonstrated and compared to traditional dissolution/precipitation extractions. …
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Development of LDPE-based antimicrobial films for food packaging
… emphasis on naturally derived AM agents and polymer films containing AM agents derived from basil, for example, exhibit an AM effect against a wide spectrum of microorganisms. Due to the relatively high temperatures involved in manufacturing such films, however, there is a considerable …
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Alkylation of phenol with methanol over H-ZSM-5, H-Beta, H-Mordenite, H-USY and H-MCM-22
… are nonionic detergents, phenolic resins, polymer additives and agrochemicals. Of the western world cresol market, 55% originates from synthetic cresols whereas 45% originates from so-called “natural” cresols obtained from coal tars and refinery caustics. The methylation of phenol is the …
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Molecular design for controlling morphology in organic electronics
… with an emphasis on morphology control in polymer bulk-heterojunction devices. Chapter 2 describes the synthesis of a class of polymer additives for bulk-heterojunction (BHJ) solar cells based on an extended triptycene-containing unit. The incorporation of these additives on BHJ …
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Improving the cold temperature properties of tallow-based methyl ester mixtures using fractionation, blending, and additives
… blending with SME and CME, and using polymer additives. TME fractionation (i.e. removal of specific methyl ester constituents) was simulated by creating FAME mixtures to match the FAME profiles of fractionated TME. The fractionation yield was found to be highest at the eutectic point …
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Bottlebrush Polymers: A Pathway to Engineering Surfaces and Interfaces
Bottlebrush polymers are macromolecules with a linear backbone and densely-grafted polymeric side-chains. Steric repulsion between the side chains forces the backbone to extend, leading to a rod or wormlike conformation. Therefore, bottlebrush polymers resemble both comb polymers and …
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Relationships between polymer additive molecular structure and intumescent flame retardant behaviour.
… structure of a range of organophosphorus-based polymer additives and their ability to confer intumescent flame retardant properties on the resulting polymers. The development of intumescent fire retardants is discussed along with the principles of flame retardancy in general. Much of the work …
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Biorenewable polymer thermoplastic biocomposites
… in nature and do not adhere well to hydrophobic polymer matrices. Directly combining plant fibers with plastics tends to yield poor mechanical properties because of this incompatibility. These plant fibers must first go through treatment(s) to alter their surface properties, mechanically and/or …
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Volumetric Properties and Viscosity of Lubricant Oils and the Effects of Additives at High Pressure and Temperatures
… viscosity of lubricant base oils modified with polymeric additives. Several groups of mineral and synthetic base oils, including Ultra S4, Ultra S8, and poly alpha olefin PAO 4 have been studied. Among the various types of additives explored were viscosity index modifiers, polyisobutylene …
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New functional polymers for sensors, smart materials and solar cells
Organic polymers can be used as the active component of sensors, smart materials, chemical-delivery systems and the active layer of solar cells. The rational design and modification of the chemical structure of polymers has enabled control over their properties and morphology, leading to the …
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Novel polymeric microcapsules for targeted drug delivery
… develop a post-ruminal delivery system based on polymeric microencapsulation. A major criterion was to develop microcapsules with reversible switching in response to changes of pH in the in vivo environment so contents could be released. The microcapsules must have a thin shell strong enough to …
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Characterize the molecular dynamics of materials for 4D printing
… patterning to fabricate 4D structures. Polymer/clay composite inks are the crux of 4D printing, however, there is a lack of fundamental understanding as to how physiochemical dynamics of the polymer/clay composite impact printability of these inks. Using a model system, …