Etched Fibers of Syndiotactic Polystyrene with Nanoporous-Crystalline Phases

Daniel, Christophe; Antico, Pasqualmorica; Guerra, Gaetano

doi:10.1021/acs.macromol.8b01044

Cited by 24 publications

(16 citation statements)

References 56 publications

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“…Syndiotactic poly(styrene) (sPS), however, was found to have more desirable physical properties. First prepared by Ishihara and co-workers, sPS featured faster crystallization kinetics, a higher T m , and an entanglement molecular weight approximately half that of iPS. − Decades of optimization have led to precise syntheses of sPS, enabled primarily by MAO-activated ansa -metallocenes. , Importantly, the advantageous properties of sPS relative to iPS, as well as the similar properties of iPS to atactic PS, highlight an imposing challenge in the field of stereoselective polymerization: predicting the properties of stereoregular vinyl polymers de novo is often unreliable. The effects of even slight differences in monomer structure can be amplified as the degree of stereocontrol is increased, leading to significant changes in morphology that give rise to divergent material properties.…”

Section: Historical Developments In Stereocontrolled Polymerizationmentioning

confidence: 99%

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization

et al. 2020

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The thermomechanical properties exhibited by synthetic macromolecules can be directly linked to their tacticity, or the relative stereochemistry of repeat units. The development of stereoselective coordination–insertion polymerization, for example, led to the discovery of isotactic polypropylene, now one of the most widely produced commodity plastics in the world. Widespread interest in controlling polymer tacticity has led to a variety of stereoselective polymerization methodologies; however, this area of polymer science has lagged behind when compared to the ability to control molecular weight, dispersity, and composition. Despite decades of advancements, many stereoregular vinyl polymers remain unknown, particularly those comprised of polar functionality or derived from renewable resources. This Viewpoint provides an overview of recent developments in stereocontrolled polymerization, with an emphasis on propagation mechanism, and highlights successes, limitations, and future challenges for continued innovation.

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Section: Historical Developments In Stereocontrolled Polymerizationmentioning

confidence: 99%

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization

et al. 2020

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“…As is well described in the literature, NC polymer samples can be useful for the removal of organic pollutants from water and air [ 20 , 21 , 22 ], in molecular sensors [ 18 , 23 ], in gas separation procedures [ 14 , 24 , 25 ], as support for catalysts [ 26 , 27 ] or even for chemical stabilization of unstable guest molecules [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Axial Orientation of Co-Crystalline Phases of Poly(2,6-Dimethyl-1,4-Phenylene)Oxide Films

et al. 2020

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Films exhibiting co-crystalline (CC) phases between a polymer host and low-molecular-mass guest molecules are relevant for many applications. As is usual for semi-crystalline polymers, axially oriented films can give relevant information on the crystalline structure, both by Wide Angle X-ray diffraction fiber patterns and by polarized Fourier-transform infrared spectroscopy. Axially oriented CC phases of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) with 1,3,5-trimethylbenzene (mesitylene) can be simply obtained by the stretching of CC PPO films. In fact, due to the plasticization effect of this highly boiling guest, PPO orientation can occur in a stretching temperature range (170–175 °C) nearly 50 °C lower than that generally needed for PPO films (220–230 °C). This low stretching temperature range allows avoidance of polymer oxidation, as well as formation of the mesomorphic dense γ PPO phase. Axially oriented CC phases of PPO with toluene, i.e., with a more volatile guest, can be instead obtained by the stretching (in the same low temperature range: 170–175 °C) of CC PPO blend films with polystyrene.

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“…Thus, the combination of high hydrophobicity and oleophilicity makes sure that δ e and ε e aerogels are superior oil/organic solvent absorbers. Guerra and co-workers showed a high sorption capacity of organic solvents even from very dilute aqueous solutions using crystalline nanoporous sPS aerogels. ,, To regenerate the δ e and ε e aerogels for further absorption process, the oil/solvent-filled aerogels were washed with ethanol and dried in an oven at 60 °C for 60 min. After the washing process, oils/organic solvents can be separated from ethanol by suitable procedures.…”

Section: Resultsmentioning

confidence: 99%

Nanoporous Crystalline Aerogels of Syndiotactic Polystyrene: Polymorphism, Dielectric, Thermal, and Acoustic Properties

et al. 2021

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Hierarchically porous crystalline nanoporous aerogels of syndiotactic polystyrene (sPS) received much attention because of their unique nanoporous structures along with meso-and macroporosity. Depending on the difference in the packing of polymer chains within the crystal lattice, sPS has two nanoporous crystalline forms, namely, δ and ε forms (δ e and ε e ). In this study, we have prepared high-purity nanoporous δ and ε forms of sPS aerogels from their respective gels using a solvent exchange strategy with green solvents, followed by an environmentally friendly freeze-drying technique. Using these highly porous aerogels, the phase transition behavior of sPS at higher temperatures was investigated. The δ e form showed a complex phase transition behavior on heating, and at a higher temperature, the γ form (obtained through an intermediate helical phase) transformed into a mixture of α and β forms. On the other hand, the ε e form transformed directly into the γ form, and on further heating, the γ form transformed exclusively into the α form. The dielectric, thermal, and acoustic properties of crystallinenanoporous aerogels were promising with an ultralow dielectric constant (1.02 ± 0.02), thermal conductivity (λ) as low as 0.04 W m −1 K −1 , and a high sound absorption coefficient (close to 1). Moreover, these aerogels exhibited excellent oleophilicity, which was demonstrated in oil/organic solvent separation experiments. These multifunctional aerogels of sPS can, therefore, find a multitude of applications, especially in thermal and acoustic insulation and molecular sorption of oil/organic solvents.

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Etched Fibers of Syndiotactic Polystyrene with Nanoporous-Crystalline Phases

Cited by 24 publications

References 56 publications

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization

Axial Orientation of Co-Crystalline Phases of Poly(2,6-Dimethyl-1,4-Phenylene)Oxide Films

Nanoporous Crystalline Aerogels of Syndiotactic Polystyrene: Polymorphism, Dielectric, Thermal, and Acoustic Properties

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