Sulfur Radical Transfer and Coupling Reaction to Benzoxazine Groups: A New Reaction Route for Preparation of Polymeric Materials Using Elemental Sulfur as a Feedstock

Abstract

A novel approach to preparing polymeric materials using elemental sulfur as a feedstock through the newly developed sulfur radical transfer and coupling (SRTC) reaction is reported herein. Polybenzoxazines with high sulfur contents are prepared using the SRTC reaction with benzoxazine compounds as the radical acceptors. The reactions between elemental sulfur and benzoxazine rings are analyzed with Fourier transform infrared (FTIR), H NMR, and C DEPT spectroscopies to elucidate the SRTC reaction mechanism. Moreover, the prepared polybenzoxazine-sulfur hybrid materials show attractive repairing properties based on the dynamic S-S linkages. An effective reaction mechanism and the prepared repairable sulfur-possessing polymeric materials are demonstrated.

Elemental sulphur in the synthesis of sulphur-containing polymers: reaction mechanisms and green prospects

“…108 Polymerisation at 432 K in the presence of elemental sulphur is not only possible for alkenes and alkynes, but also for other compounds that can act as chain transfer agents in relation to oligosulphide radicals, such as N-phenylbenzoxazine (Scheme 4). 109 Aliphatic 110 and aromatic 111 dithiols can be used as chain transfer agents, which lead to the formation of their corresponding polymeric polysuldes (Scheme 5). This reaction usually takes place at 400 K using nucleophilic catalysis.…”

Cardanol Benzoxazines: A Versatile Monomer with Advancing Applications

“…The oxazine ring opening occurring via radical mechanism is not mentioned by the authors. It is reported that Bz monomers possess radical transfer agent characteristics and assist sulfur radical transfer and coupling reactions between S 8 and organic compounds . Elemental S 8 trigger the formation of intermediate Schiff bases from benzoxazine rings at 120 °C suggesting occurrence of benzoxazine ring‐opening reaction.…”

Preparation and Modification of Biomass-Based Functional Rubbers for Removing Mercury(II) from Aqueous Solution

“…1,3-diisopropenyl benzene (DIB) was used to stabilize polysulfide chains in inverse vulcanization as a cross-linker [8]. Sulfur-containing polymers obtained by using various cross-linkers were reported, and these polymers showed great application potentials for solid electrodes, optical materials and heavy metal remediation [9][10][11][12][13][14][15][16]. In order to meet the needs of green and sustainable chemistry, it would be desirable to employ renewable and sustainable bio-based materials to combine with sulfur for preparing functional materials.…”