The utilization of carbon dioxide as a polymer feedstock is an ongoing challenge. This report describes the catalytic conversion of carbon dioxide and an olefin comonomer, 1,3-butadiene, into a polymer structure that arises from divergent propagation mechanisms. Disubstituted unsaturated δ-valerolactone 1 (EVL) was homopolymerized by the bifunctional organocatalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) to produce a hydrolytically degradable polymer. Isolation and characterization of reaction intermediates using 1H, 13C, COSY, HSQC, and MS techniques revealed a vinylogous 1,4-conjugate addition dimer forms in addition to polymeric materials. Polymer number-average molecular weights up to 3760 g/mol and glass transition temperatures in the range of 25–52 °C were measured by GPC and DSC, respectively. The polymer microstructure was characterized by 1H, 13C, FTIR, MALDI-TOF MS, and ESI tandem MS/MS. The olefin/CO2-derived materials depolymerized by hydrolysis at 80 °C in 1 M NaOH. This method and the observed chemical structures expand the materials and properties that can be obtained from carbon dioxide and olefin feedstocks.
Ever since the inception of synthetic polymeric materials in the late 19th century, the number of studies on polymers as well as the complexity of their structures have only increased. The development and commercialization of new polymers with properties fine‐tuned for specific technological, environmental, consumer, or biomedical applications requires powerful analytical techniques that permit the in‐depth characterization of these materials. One such method with the ability to provide chemical composition and structure information with high sensitivity, selectivity, specificity, and speed is mass spectrometry (MS). This tutorial review presents and exemplifies the various MS techniques available for the elucidation of specific structural features in a synthetic polymer, including compositional complexity, primary structure, architecture, topology, and surface properties. Key to every MS analysis is sample conversion to gas‐phase ions. This review describes the fundamentals of the most suitable ionization methods for synthetic materials and provides relevant sample preparation protocols. Most importantly, structural characterizations via one‐step as well as hyphenated or multidimensional approaches are introduced and demonstrated with specific applications, including surface sensitive and imaging techniques. The aim of this tutorial review is to illustrate the capabilities of MS for the characterization of large, complex polymers and emphasize its potential as a powerful compositional and structural elucidation tool in polymer chemistry.
Three sets of polyoxometalate (POM)‐based amphiphilic hybrid macromolecules with different rigidity in their organic tails are used as models to understand the effect of molecular rigidity on their possible self‐recognition feature during self‐assembly processes. Self‐recognition is achieved in the mixed solution of two structurally similar, sphere‐rigid T‐shape‐linked oligofluorene(TOF4) rod amphiphiles, with the hydrophilic clusters being Anderson (Anderson‐TOF4) and Dawson (Dawson‐TOF4), respectively. Anderson‐TOF4 is observed to self‐assemble into onion‐like multilayer structures and Dawson‐TOF4 forms multilayer vesicles. The self‐assembly is controlled by the interdigitation of hydrophobic rods and the counterion‐mediated attraction among charged hydrophilic inorganic clusters. When the hydrophobic blocks are less rigid, e.g., partially rigid polystyrene and fully flexible alkyl chains, self‐recognition is not observed, attributing to the flexible conformation of hydrophobic molecules in the solvophobic domain. This study reveals that the self‐recognition among amphiphiles can be achieved by the geometrical limitation of the supramolecular structure due to the rigidity of solvophobic domains.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.