Cationic grafting from carbon black. III. Grafting of polyesters from carbon black by ring-opening polymerization of lactones initiated by COClO4 groups on carbon black

1985 ◽  
Vol 30 (5) ◽  
pp. 2041-2049 ◽  
Author(s):  
Norio Tsubokawa
Keyword(s):  
Carbon Black ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Grafting From

Silk sericin as a bio-initiator for grafting from synthesis of polylactide via ring-opening polymerization

2019 ◽  
Vol 121 ◽  
pp. 109265 ◽  
Author(s):  
Kanittha Boonpavanitchakul ◽  
Suwatchai Jarussophon ◽  
Nuttaporn Pimpha ◽  
Wiyong Kangwansupamonkon ◽  
Rathanawan Magaraphan
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Silk Sericin ◽  
Grafting From

Novel Amphiphilic Star-Shaped Poly(2-Oxazoline)s with Calix[4]Arene Branching Center

2021 ◽  
Vol 899 ◽  
pp. 300-308
Author(s):  
Aleksei N. Blokhin ◽  
Alla B. Razina ◽  
Andrey V. Tenkovtsev
Keyword(s):  
Aqueous Solutions ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Arene Derivative ◽  
Vis Spectroscopy ◽  
Gel Permeation ◽  
Grafting From ◽  
Cationic Ring Opening Polymerization

Novel amphiphlic four-arm star-shaped poly (2-alkyl-2-oxazoline) s with calix [4] arene core were synthesized using the “grafting from” approach. The chlorosulfonated calix [4] arene derivative was synthesized and successfully applied as a multifunctional initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines. Obtained star-shaped poly (2-alkyl-2-oxazoline) s were characterized by means of NMR, UV-Vis spectroscopy and gel-permeation chromatography. It was shown that star-shaped poly (2-isopropyl-2-oxazoline) perform thermosensitivity in aqueous solutions.

scholarly journals Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

2014 ◽  
Vol 10 ◽  
pp. 2573-2579 ◽  
Author(s):  
Kazuaki Kato ◽  
Katsunari Inoue ◽  
Masabumi Kudo ◽  
Kohzo Ito
Keyword(s):  
Polyethylene Glycol ◽  
Inclusion Complex ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Kinetic Control ◽  
Basic Catalyst ◽  
Grafting Polymerization ◽  
Grafting From ◽  
Hydroxy Groups ◽  
End Group

Graft polyrotaxanes, with poly(ε-caprolactone) (PCL) graft chains on the ring components were synthesized by the simultaneous ring-opening polymerization of ε-caprolactone from both ends of the backbone polymer, an end-functionalized polyethylene glycol (PEG) and the formation of inclusion complexes with α-cyclodextrin (α-CD). PEG with multiple functional groups at each end was prepared by the condensation of PEG-amine and D-gluconic acid; the PEG derivative formed an inclusion complex with α-CD. The polymerization of multiple hydroxy groups at the backbone ends resulted in a star-shaped end group, which served as a bulky capping group to prevent dethreading. In contrast, PEG with only one hydroxy group at each end did not produce polyrotaxanes, indicating that single PCL chains were too thin to confine α-CDs to the complex. In addition, the grafting polymerization proceeded properly only when robust hydrogen bonds formed between α-CDs were dissociated using a basic catalyst. Since the dissociation also induced dethreading, kinetic control of the polymerization and dissociation were crucial for producing graft polyrotaxanes. Consequently, this three-step reaction yielded graft polyrotaxanes in a good yield, demonstrating a significant simplification of the synthesis of graft polyrotaxanes.

scholarly journals Water-Assisted and Protein-Initiated Ring-Opening Polymerization of Proline N-Carboxyanhydride

2021 ◽  
Author(s):  
Yali Hu ◽  
Zi-You Tian ◽  
wei xiong ◽  
HUA LU
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Biological Activities ◽  
Functional Materials ◽  
Monomer Conversion ◽  
Ring Opening Polymerization ◽  
Type I ◽  
Stringent Requirement ◽  
Native Proteins ◽  
Grafting From

<p>The production of poly-<sub>L</sub>-proline (PLP) via the ring-opening polymerization (ROP) of <sub>L</sub>-proline <i>N</i>-carboxyanhydride (ProNCA) is challenging due to a combination of factors, including the stringent requirement of moisture-free conditions, slow monomer conversion, poor control of the molar mass, and premature precipitation of the product in the form of polyproline type I helix. Here, we report water-assisted ROP of ProNCA, which affords well-defined PLP in polyproline II helix in 2-5 minutes. Density functional theory reveals an as-yet-unreported role of water in facilitating proton shift that significantly lowered the energy barrier of the chain propagation. Protein-mediated ROP of ProNCA conveniently affords various protein-PLP conjugates via a grafting-from approach. PLP conjugation not only preserves the biological activities of the native proteins, but also enhances the stability of proteins against extreme conditions. This work provides a simple means and new mechanistic insight to solve a longstanding problem in PLP synthesis and will offer valuable guidance for the development of water-resistant ROP of other NCAs. The facile access of PLP can greatly boost the application potentials of PLP-based functional materials.<b></b></p>

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