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Results for “Polymer science”
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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Complexation between Oppositely Charged Polyelectrolytes in Dilute Solution: Effects of Charge Asymmetry
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Structure–Property Relationships for Polyether-Based Electrolytes in the High-Dielectric-Constant Regime
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Impact of Side-Chain Length on the Self-Assembly of Linear-Bottlebrush Diblock Copolymers
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Molecular Dynamics Simulations of the Effects of Entanglement on Polymer Crystal Nucleation
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Triblock Terpolymer Thin Film Nanocomposites Enabling Two-Color Optical Super-Resolution Microscopy
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Miniemulsion SI-ATRP by Interfacial and Ion-Pair Catalysis for the Synthesis of Nanoparticle Brushes
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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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