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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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User Guide to Ring-Opening Metathesis Polymerization of endo -Norbornene Monomers with Chelated Initiators
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Tuning Diblock Copolymer Particle Packing Symmetry with Variable Molecular Weight Core-Homopolymers
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Understanding the Aggregation and Flow Response of Donor–Acceptor Conjugated Polymers
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Scalable Frontal Oligomerization: Insights from Advanced Mass Analysis
Linear oligomers of dicyclopentadiene (DCPD) are reactive precursors for thermoplastic and thermoset materials. Unlike the foul-smelling parent monomer, oligomers composed of DCPD are odorless. With appropriate modification of the end-group or backbone chemistry, telechelic DCPD oligomers have potential utility as cross-linkers and as macromonomer precursors for block and graft copolymers. Most existing methods to produce oligo-DCPD, however, require solvent, are relatively slow, and necessitate air-free techniques. Here we show that frontal ring-opening metathesis oligomerization (FROMO) of neat DCPD and other norbornene derivatives rapidly generates hundreds of grams of material in minutes with catalyst loadings of 0.5 mM. This energy-efficient catalytic process utilizes the heat generated by the reaction to self-propagate oligomerization throughout the liquid monomer. FROMO employs a terminal olefin (e.g., styrene) in which a cross-metathesis reaction (i.e., chain transfer) competes with ring-opening metathesis (i.e., propagation). Kendrick mass analysis enables rapid identification and assignment of all the chain-end types present and quantifies the degree of branching resulting from the infrequent cyclopentene ring-opening reaction. This analytical technique also detects oligomer species derived from trace impurities in the monomer or chain-transfer agent that are otherwise difficult to observe with other characterization methods. Here, the obtained oligomers possess well-defined chain-ends and molecular weight distributions.
Fragile Glass Formation and Non-Arrhenius Upturns in Ethylene Vitrimers Revealed by Dielectric Spectroscopy
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Triblock Elastomeric Vitrimers: Preparation, Morphology, Rheology, and Applications
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Simulation and Experiment of CO 2 Philicity and Separation in Carbonate-Rich Polymers
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Composition-Tolerant Terpolymers for Efficient, Nonhalogenated Solvent-Processed Polymer Solar Cells
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Impact of Photoactive Monomer Location in Photoresponsive Block Copolymer/Ionic Liquid Solutions
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Impact of Ionic Correlations on Selective Salt Transport in Ligand-Functionalized Polymer Membranes
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Structure and Phase Behavior of Bottlebrush Diblock Copolymer-Linear Homopolymer Ternary Blends
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Polymerization of Primary Amines with Sulfur Monochloride to Yield Red Polymers with a Conjugated SN Backbone
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