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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 54 for “"crosslink density"”.
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Correlation of permeability, hydration, and crosslink density in polyelectrolyte hydrogel membranes
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.
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Effects of degradation rate and crosslink density of artificial skin on wound contraction
Thesis: M.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1986
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Fundamental Importance of Fillers, Cure Condition, and Crosslink Density on Model Epoxy Properties
… shrinkage. The influence of the model epoxy crosslink density was examined by varying the content of 1,4-butanediol in the model system. Addition of 1,4-butanediol led to a decrease in the modulus and glass transition temperature, which resulted in a reduction in residual stress and …
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Effect of Crosslink Density on the Tearing of Gum Natural Rubber Cured with Dicumyl Peroxide (DCP)
… peroxide (DCP) was studied. The effect of crosslink density on tensile strength, tear strength, strain, 100% modulus, and the critical cut size was determined. Dumbbell specimens cured with different level of DCP with (normal tensile test) and without (tear test) edge cuts, were strained …
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About the gel structure of lignin
… weight increases as delignification procedes. As crosslink density is a function of alkyl-aryl ether content, these results suggest that the 6 7 crosslink density of the sol fraction decreases while molecular weight increases. This contradicts to the theoretical behavior for the degradation of an …
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Synthesis and Characterization of Nitrile Containing Polysiloxanes and Their Corresponding Networks as Aircraft Sealant Materials
… a basic catalyst. These oligomers were then crosslinked with various hydride functional crosslinking reagents to yield model networks for mechanical and adhesion studies. The network properties of nonpolar polydimethylsiloxane (PDMS), polar poly[methyl(3,3,3-trifluoropropyl)siloxane] …
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Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape-memory polymer networks
… varying sidegroup structure and multi-functional crosslinkers with varying mole fraction and functionality. Fundamental trends are established between the network chemical structure, crosslink density, glass transition temperature, rubbery modulus, failure strain, and toughness. The glass …
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Development of Functional Polymeric Materials for Microfluidic Systems
… The relationship between the hydrogel crosslink density and the hydrogel volume has been studied in detail. In addition, dissolvable hydrogels based on de-crosslinking have been demonstrated, and the factors that affect dissolution kinetics have been understood through systematic …
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Topology and Telechelic Functionality Control in Polyester Design
… of linear, long-chain branched, and novel crosslinked polyesters for applications spanning from pressure sensitive adhesives to biomedical applications. Altering polymer topology and functionality using different synthetic strategies was enabled tailoring the thermomechanical, rheological, …
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Effect of network structure on lignin-derived polyurethane film properties
… films were prepared from solution by crosslinking hydroxypropyl lignin derivatives with diisocyanates. The network structure, characterized by the crosslink density, was controlled by two variables: the hydroxy content of the lignin polyol and the molar ratio of NCO:OH. In addition, …
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Statistical Mechanics of the Amorphous Solid State of Randomly Cross-Linked Macromolecules
… i.e., with the third power of the excess crosslink density. It is also found that, quite surprisingly, the external stresses do not spoil the spherical symmetry of the localization clouds of the particles near the transition.
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Degradation and stabilisation of diisocyanate cured polybutadiene
… that oxygen is the main factor which causes the crosslinking and chain scission reactions. The former is the predominant reaction and proceeds rapidly under oxygen sufficient environment. The unsaturation of polymer chain, which provides the desired physical properties to the binder, was lost …
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Fundamental Analysis of Wood Adhesion Primers
… alkyl-HMR (a-HMR), an HMR variant having reduced crosslink density, and a 5% solution of polymeric methylenebis(phenylisocyanate) in N-methylpyrrolidone (solution referred to as "pMDI"). The experimental system was red oak (Quercus rubra) bonded with a moisture-cure polyurethane adhesive (PUR). …
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Friction, wear and lubrication of a poly(2-hydroxyethyl methacrylate) hydrogel
… were load, lubrication, hydration and material crosslink density. Linear oscillating sliding contact tests were performed on each polyHEMA disc for approximately 30 minutes per test. Friction coefficients found ranged from 0.05 to 1.7. Linear wear measured ranged from 0.02 mm to 1.32 mm.
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Hypotheses for Scratch Behavior of Polymer Systems that Recover
… based upon the hardness of a material or its crosslink density is incorrect. In this thesis, novel polymers were tested in an attempt to discover materials that show excellent scratch recovery - one of the most important parameters in determining the wear of a material. Several hypotheses were …
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Pressure-Property Relationships in High-Performance Elastomers
… and its relationship with gas solubility, crosslink density, loading and types of filler, and chemical structure under pressure, were investigated. It was observed that absorbed gas molecules have a significant impact on the change of Tg with pressure. We note that the Tg of the …
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Synthesis of environmentally-friendly polyurethane dispersions based on soybean oil- derived polyols and their applications in advanced water-based and uv-cure coatings
… discussed. Also, the PUDs !! vi! were self-crosslinked with carbodiimide and excellent water resistance and oil resistance coatings were achieved from this research.</p> <p>For ultraviolet curable coatings, novel hydroxylated acrylic epoxidized soybean oil was synthesized from commercially …
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Crosslinking and Entanglement Effects in Polybutadiene
… have been used to investigate the effects of crosslinking and entanglements on segmental motion in polybutadiene. The temperature dependence of T(,1), the spin-lattice relaxation time, T(,2), the spin-spin relaxation time, and T(,1(,(rho))), the spin-lattice relaxation time in the rotating …
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Critical thickness in silicone resin
… then decreased at the highest cure temperature. Crosslink density is theorized as the cause for this cure temperature induced alteration of the critical thickness.
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The Vulcanization Transition and the Amorphous Solid State It Yields: A Statistical Mechanical Perspective
The vulcanization transition is a crosslink-density-controlled equilibrium phase transition from the liquid to the amorphous solid state. In order to understand the origins and consequences of the universal aspects of this transition and the emergent solid state, we construct a minimal model in the …
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