Next Article in Journal
Development of Surface-Coated Polylactic Acid/Polyhydroxyalkanoate (PLA/PHA) Nanocomposites
Next Article in Special Issue
Characteristics and Mechanism of Vinyl Ether Cationic Polymerization in Aqueous Media Initiated by Alcohol/B(C6F5)3/Et2O
Previous Article in Journal
Comparison of Adhesive Properties of Polyurethane Adhesive System and Wood-plastic Composites with Different Polymers after Mechanical, Chemical and Physical Surface Treatment
Previous Article in Special Issue
Synthesis of Polyazobenzenes Exhibiting Photoisomerization and Liquid Crystallinity
Article Menu
Issue 3 (March) cover image

Export Article

Open AccessArticle

Effects of End-Caps on the Atropisomerization, Polymerization, and the Thermal Properties of ortho-Imide Functional Benzoxazines

1
Research School of Polymeric Materials, School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
2
Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK
*
Authors to whom correspondence should be addressed.
Polymers 2019, 11(3), 399; https://doi.org/10.3390/polym11030399
Received: 5 February 2019 / Revised: 20 February 2019 / Accepted: 22 February 2019 / Published: 1 March 2019
(This article belongs to the Collection Design and Synthesis of Polymers)
  |  
PDF [3682 KB, uploaded 1 March 2019]
  |  

Abstract

A new type of atropisomerism has recently been discovered in 1,3-benzoxazines, where the intramolecular repulsion between negatively charged oxygen atoms on the imide and the oxazine ring hinders the rotation about the C–N bond. The imide group offers a high degree of flexibility for functionalization, allowing a variety of functional groups to be attached, and producing different types of end-caps. In this work, the effects of end-caps on the atropisomerism, thermally activated polymerization of ortho-imide functional benzoxazines, and the associated properties of polybenzoxazines have been systematically investigated. Several end-caps, with different electronic characteristics and rigidities, were designed. 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) calculations were employed to obtain structural information, and differential scanning calorimetry (DSC) and in situ Fourier transform infrared (FT-IR) spectroscopy were also performed to study the thermally activated polymerization process of benzoxazine monomers. We demonstrated that the atropisomerization can be switched on/off by the manipulation of the steric structure of the end-caps, and polymerization behaviors can be well-controlled by the electronic properties of the end-caps. Moreover, a trade-off effect were found between the thermal properties and the rigidity of the end-caps in polybenzoxazines. View Full-Text
Keywords: benzoxazine; ortho-imide; atropisomerization; thermal properties benzoxazine; ortho-imide; atropisomerization; thermal properties
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material

SciFeed

Share & Cite This Article

MDPI and ACS Style

Zhang, K.; Liu, Y.; Shang, Z.; Evans, C.J.; Yang, S. Effects of End-Caps on the Atropisomerization, Polymerization, and the Thermal Properties of ortho-Imide Functional Benzoxazines. Polymers 2019, 11, 399.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Polymers EISSN 2073-4360 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top