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Showing 1 to 20 of 34 for “"soft segment"”.
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Determining soft segment structure-property effects in the enhancement of segmented polyurethane performance
Liquid Crystalline Elastomer (LCE)-inspired segmented polyurethane elastomers possessing widely different extents of ordering were created to mimic the hierarchical structure of the continuous matrix and superior mechanical performance of spider silk fibers. The silk's remarkable toughness …
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PEO-containing copolymers as polyurethane soft segments in the development of high performance materials
Silk-inspired segmented polyurethanes containing flexible, hydrophilic segments with crystalline and liquid crystalline moieties were developed to mimic the hierarchical morphology of the continuous domain in and the superior mechanical properties of native spider silk. A series of polyurethane …
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Characterization of Structure-Property Relationships of Poly(urethane-urea)s for Fiber Applications
… employing poly(tetramethylene ether glycol) as soft segments. Recent developments in catalyst technology have resulted in the production of ultra-low monol content poly(propylene glycol) (PPG), which is nearly difunctional (f=1.95+). This enhancement in difunctionality has potentially enabled …
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Structure-property relationships in segmented copolymers
The structure-property relationships for various segmented copolymers were investigated. A number of mechanical and thermal characteristics were determined. The morphology was characterized by SAXS with respect to size and dispersion of domains; degree of phase separation and the domain interfacial …
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Synthesis and Properties of Ion-Containing Block and Segmented Copolymers and Their Composites
Ion-containing segmented polyurethanes exhibit unique morphology and physical properties due to synergistic interactions of electrostatic, hydrogen bonding, and hydrophobic interactions. A fundamental investigation on a series of well-defined ion-containing polyurethanes elucidated the influence of …
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Synthesis and Characterization of Branched Macromolecules for High Performance Elastomers, Fibers, and Films
… dynamic mechanical analysis. The similarity in soft segment glass transition behavior and mechanical properties of the branched systems with that of the linear analogues suggested these materials have considerable promise for a variety of applications. When a polycaprolactone triol was utilized …
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Biodegradable Thermoplastic Elastomers and Smart Composites
… polyurethane that has a biodegradable soft segment and a crystalline hard segment (POSS). By varying the composition of the poly(caprolactone)-based soft segment as well as the soft segment to hard segment ratio, the thermal and mechanical properties could be controlled. Increasing the …
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Design, synthesis and characterization of side chain liquid crystal segmented polyurethanes
… of polyurethanes are made with traditional hard segments and cyano-biphenyl mesogens pendant on the soft segment. The synthesis of the soft segment macrodiol. a carbinol endcapped hydromethylsiloxane oligomer that can be functionalized with mesogen via a hydrosilylation technique, is effected by …
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Structure-property relationships in polyurethanes from lignin
… addresses the effect of synthesis variables and soft segment incorporation on the thermal and mechanical properties. The first part of the study examined the effect of lignin type, of diisocyanate type and of composition (NCO/OH ratio). Stoichiometric excess was found to cause a significant …
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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
… <p>The indigenous soy-polyol was used as soft segment polymeric chain backbone of aqueous PUD. The PUDs with varying soft segment to hard segment ratios were developed and characterized for film properties, surface properties, chemical resistance, and thermal properties. The PUD (55% bio …
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Fundamental Investigations of Hazardous Gas Uptake and Binding in Metal-Organic Frameworks and Polyurethane Films
… uptake into polyurethane films of varying hard:soft segment compositions revealed that dipole-dipole and dipole-induced dipole interactions were responsible for favorable absorption conditions. Furthermore, the ratio of hard and soft segment components of the polyurethane had a minor impact on …
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Investigation of the Influence of Selected Variables on the Solid State Structure-Property Behavior of Segmented Copolymers
Segmented copolymers are a commercially important class of materials that are utilized in a wide variety of applications. In these systems a relatively large number of variables such as backbone chemistry, segment molecular weight, and the overall molecular weight of the copolymer can be …
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Tailored Architectures of Ammonium Ionenes
… endothelial cell line. A series of low hard segment (HS) content, poly(propylene glycol) (PPG)-based ammonium ionenes were synthesized using a Menshutkin reaction from bromine end-capped PPG oligomers (prepared using acid-chloride reactions) and N,N,Nâ ²,Nâ ²-tetramethyl-1,6-hexanediamine. …
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Siloxane modified polyurea and polyurethane urea segmented copolymers
… coordination polymerization. The resulting segmented copolymer showed much higher tensile strength and better thermal stability than polyureas based on commercial PPO which contains some terminal unsaturation. This was attributed to the achievement of both higher molecular weight and to more …
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Structure-property relationships of lignin-based isocyanate and amine adhesives for wood
… indicated that the lignin component may act as a soft segment blocks or domains in a more rigid polymer matrix. Particle board was produced with the lignin adhesives with: (a) properties equal to those produced with commercial OF resins; (b) spray application greatly reducing the effects of …
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Effects of Polybenzoxazine on Properties of Shape-Memory Polyurethanes with Glassy and Crystalline Soft Segments
… was determined by the glassy or crystalline soft domain of polyurethanes (PU) with respectively glass transition temperature (Tg) or melting temperature (Tm). The study exploited the miscibility of the benzoxazine monomer with the PU prepolymer. The benzoxazine monomer was polymerized into PB …
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Solution History Effects and Crystal Phase Transformation in Polybutene-1 and Domain Morphology in Polyurethanes
… polyurethanes composed of alternating hard and soft segments have been shown to be composed of two phases. The hard and soft segments tend to aggregate individually to form hard- and soft-segment domains which are believed to be responsible for the unusual physical and mechanical properties …
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Synthesis and characterization of polydimethylsiloxane-polyamide segmented copolymers
… is feasible. Polyamide-polydimethylsiloxane segmented or block copolymers were found to be suitable "interfacial" agents. They were synthesized by reacting aminopropyl-terminated polydimethylsiloxane (PDMS) oligomers with sebacyl chloride via an interfacial polymerization in which methylene …
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Structure–Property Relationships Of: 1) Novel Polyurethane and Polyurea Segmented Copolymers and 2) The Influence of Selected Solution Casting Variables on the Solid State Structure of Synthetic Polypeptide Films Based on Glutamate Chemistry
… dissertation concern the characterization of segmented polyurethanes and polyureas synthesized without the use of chain extenders'molecules that are typically used to promote a microphase separated morphology that gives these materials their useful characteristics. Polyurethanes in which a …
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Structure-Property Relationships of Flexible Polyurethane Foams
… structures. These changes were shown to lead to softening of the foam. Copolymer polyol is frequently applied as reinforcing filler in foams. It was found that a common method of adding this component alters the hard segment/soft segment (HS/SS) ratio, thus increasing the load bearing capacity of …
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