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 50 for “"plasticization"”.
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The attempted plasticization of cellulose from cellulose xanthate
This investigation was started at the suggestion of Dr. P. C. Scherer who suggested that a film prepared from a cellulose xanthate, in which the fiber form had been destroyed by some action other than by dilute alkali, should have interesting properties. The possibilities of such a material might …
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Vacuum Steam Technology for Rapid Plasticization and Bending of Maple
… adding moisture and heat to wood results in plasticization. Steaming at atmospheric pressure is the common technique for wood bending where diffusion prevails as the predominant mechanism governing moisture movement. Applications using conventional atmospheric steaming are time consuming and …
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Optimizing the structure and plasticization resistance of asymmetric polyimide hollow fiber membranes for CO2 removal from natural gas
… to gain a comprehensive understanding of the plasticization phenomenon and to link the bridge between membrane formation mechanisms with membrane morphology and plasticization phenomenon. Gas sorption tests were performed on the in-house fabricated Matrimid hollow fibers with various ranges of …
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Polyimide-Organosilicate Hybrid Materials: Part I: Effects of Annealing on Gas Transport Properties; Part II: Effects of CO2 Plasticization
… evaluate how the hybrid materials reacted to CO₂ plasticization. Steady-state gas permeation experiments were performed at 35°C using pure CO₂ and CH₄ gases at feed pressures ranging from 4 to 30 atm. All four materials exhibited dual mode sorption up to feed pressures of 17 atm, at which point …
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Preparation and Properties of Flexible Resin Sheets From Zein
Overall, plasticization of zein with oleic and linoleic acids resulted in thermoplastic and moldable resins potentially useful for manufacturing flexible packaging materials. Methods of plasticizer incorporation influenced effectiveness of plasticization. Stabilizing and enhancing of …
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Preparation of Zein-Based Biodegradable Materials and Investigation of Their Physical Properties
Plasticization was improved by dissolving zein and fatty acids in warm aqueous alcohol solutions. Resins were obtained through precipitation and kneading treatments. Inclusion of palmitic and stearic acid in the formulation resulted in harder resins that were suited for rolling into sheets; whereas …
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Highly productive ester crosslinkable composite hollow fiber membranes for aggressive natural gas separations
… polymeric membranes suffer from CO₂ induced plasticization, which reduces CO₂/CH₄ separation efficiency significantly. Covalent ester-crosslinking can improve the plasticization resistance by controlling the segmental chain mobility in the polymer; however, only relatively thick selective …
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Comparison of conventional and super-glassy polymers
… show a strong tendency to physical aging and plasticization, which lead to changes in their performance with time. Up to know, it is not fully understood how these drawbacks are connected to the internal molecular mobility. In this study, a commonly used non-porous polyimide for gas separation …
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Designing Microporous Polymers for Separations
… 1. Gas sorption, diffusion, and CO₂-induced plasticization are reported. Competitive sorption effects are studied using 50:50 mixture of CO₂/CH₄. Separation performance at different compositions of CO₂/CH₄ is also explored. In Chapter 3, we incorporate nitrile functionality into the structure …
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Characterizing Mechanical and Gas Transport Properties of Nitrile Norbornene (NN) ROMP in Preparation for Analysis of OMe-NN-ROMP Block Copolymers
… did plasticize in intervals and the specific plasticization pressure is higher than 5 bar which is the CO₂-induced plasticization pressure point for the OMe-nitrile norbornene ROMP one-pot copolymers. Forming a block copolymer using nitrile norbornene ROMP with OMe-ROMP has potential for …
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THE EFFECT OF WATER ON THE PHYSICAL PROPERTIES OF EPOXIDES
… was found to involve two processes, namely plasticization and cross linking; the predominant effect depends on the particular system. Water absorption in epoxides was found to seriously depress the glass transition temperature (Tg), which explains the reason for the deterioration in the …
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Free Volume Manipulation Techniques of Polymer Membranes for Gas Separations
… transport properties, as well as unprecedented plasticization and physical aging resistance. The excellent stability exhibited by ROMP polymers was attributed to the rigid side chains. The effect of side-chain length on the gas transport properties of a methoxy-functionalized ROMP (OMeROMP) was …
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Microporous Polymer-Metal Organic Framework (MOF) Hybrid Materials for Separations
… polymers can mitigate stability issues such as plasticization, swelling, and physical aging. This thesis investigates MMMs based on PIM-1 and its derivatives, along with UiO MOFs, for gas and organic solvent-based separations. The studies focus on enhancing polymer–MOF interfacial compatibility, …
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Effect of intermediate solvents on poly(ether ether ketone)
… performed on completely swollen PEEK specimens. Plasticization and delocalized crazing were found in the case of amorphous PEEK exposed to the three solvents and semi-crystalline PEEK exposed to methylene chloride, while classical crazing occurred in the other specimens. Finally, an amorphous …
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Benign Processing of High Performance Polymeric Foams of Poly(arylene ether sulfone)
… reduced glass transition temperature (Tg) due to plasticization of the polymer. It was determined that 2 hours was sufficient time to saturate the PAES with water and scCO2 when subjected to a temperature of 220 oC and 10.3 MPa of pressure. Under these conditions, a combination of 7.5% of water …
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DEVELOPMENT OF BIO-ACTIVE FOOD PACKAGING FILMS
… of GSE that led to significant improvement in plasticization, hydrophilicity and inhibition of the growth of Escherichia coli. Albeit it did not change the film morphology as PCL and chitosan remained in immiscible phases. Biodegradation in soil compost over 16 weeks had films with lower MW …
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Mixed-gas Transport in Microporous Polymer Derivatives for Energy-Efficient Gas Separations
… overall separation performance and reducing plasticization. Despite the surge in available material platforms for membrane-based separations, the performance and fundamental underpinnings of binary and ternary mixed-gas transport in these microporous polymers and MMMs remains underexplored. …
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Characterisation of Silsesquioxane-Poly(Methyl Methacrylate) blends
… the Silsesquioxanes within Vitolane™ cause a plasticization effect in the lower inclusion compositions.
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Development of a Humidity-Resistant Coating to Impart High Oxygen Barrier Performance to Food Packaging Films
… with these coatings is also susceptible to a plasticization effect when exposed to high humidity, since water vapor molecules are readily soluble in typically hydrophilic resins. In this work, we demonstrate a 1 – 2 micron thick oxygen barrier coating, prepared on a 12 micron poly(ethylene …
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Room Temperature Ionic Liquid (Rtil) Membranes For Bio-Methane Dehumidification
… and the susceptibility of polymer materials to plasticization by H2O [6]. Water vapor does not plasticize room temperature ionic liquid membranes (RTIL-membranes) according to literature data, and RTIL-membranes have water/CH4 selectivities > 6000. In this paper we will build on the initial …
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