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

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.

Download Full-text

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

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.10.269 ◽

2014 ◽

Vol 10 ◽

pp. 2573-2579 ◽

Cited By ~ 5

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.

Download Full-text

Novel comb-structured-polymer-grafted carbon black by surface-initiated atom transfer radical polymerization and ring-opening polymerization

Journal of Applied Polymer Science ◽

10.1002/app.31142 ◽

2010 ◽

Vol 117 (2) ◽

pp. 824-827 ◽

Cited By ~ 8

Author(s):

Qiang Yang ◽

Li Wang ◽

Jia Huo ◽

Jianhua Ding ◽

Weidong Xiang

Keyword(s):

Carbon Black ◽

Atom Transfer Radical Polymerization ◽

Radical Polymerization ◽

Ring Opening ◽

Ring Opening Polymerization ◽

Atom Transfer

Download Full-text

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

10.26434/chemrxiv.14663883 ◽

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

The production of poly-L-proline (PLP) via the ring-opening polymerization (ROP) of L-proline N-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.

Download Full-text