Selective Oxidation of Polysulfide Latexes to Produce Polysulfoxide and Polysulfone in a Waterborne Environment

Abstract

Polymers containing sulfur centers with high oxidation states in the main chain, polysulfoxide and polysulfone, display desirable properties such as thermomechanical and chemical stability. To circumvent their challenging direct synthesis, methods based on the oxidation of a parent polysulfide have been developed but are plagued by uncontrolled reactions, leading either to ill-defined mixtures of polysulfoxides and polysulfones or to polysulfones with reduced degrees of polymerization due to overoxidation of the polymer. We developed an alternative method to produce well-defined polysulfoxide and polysulfone in a waterborne colloidal emulsion using different oxidants to control the oxidation state of sulfur in the final materials. The direct oxidation of water-based polysulfide latexes avoided the use of volatile organic solvents and allowed for the control of the oxidation state of the sulfur atoms. Oxidation of parent polysulfides by tert -butyl hydroperoxide led to the production of pure polysulfoxides, even after 70 days of reaction time. Additionally, hydrogen peroxide produced both species through the course of the reaction but yielded fully converted polysulfones after 24 h. By employing mild oxidants, our approach controlled the oxidation state of the sulfur atoms in the final sulfur-containing polymer and prevented any overoxidation, thus ensuring the integrity of the polymer chains and colloidal stability of the system. We also verified the selectivity, versatility, and robustness of the method by applying it to polysulfides of different chemical compositions and structures. The universality demonstrated by this method makes it a powerful yet simple platform for the design of sulfur-containing polymers and nanoparticles.

Stereoselective Ring-Opening Polymerization of Lactones with a Fused Ring Leading to Semicrystalline Polyesters

“…Sulfur-containing polymers have been reported to be vulnerable to oxidization in presence of oxidants such as 3-chloroperbenzoic acid (mCPBA). 80 Upon treating P(M2) (M n = 30.9 kDa, D̵ = 1.08, produced by [M2]/[Zn1]/ [I] = 200/1/1, P r = 0.85) with an excess amount of mCPBA in DCM solution at 0 °C, a pure oxidized product P(M2)-SO 2 was collected with 72% yield by vacuum filtration. 1 H NMR analysis demonstrated significant peak shifting for P(M2)-SO 2 (Figure S41) compared with its parent P(M2).…”

Fabrication of Oxidative and pH Dual-Responsive Photonic Crystals Based on Sulfide-Containing Block Copolymers

“…The concentration of PVS was 10 –2 mol L –1 . The results revealed that PVS can be first oxidized to sulfoxide at 1.74 V (Figure A), and it can be further oxidized to sulfone groups at 2.00 V. The oxidized groups can be reduced to sulfide groups at −1.27 V . Such a result indicated that the sulfide group in P­(PVS) could be selectively oxidized to form sulfoxide (named P­(PVSO)) or sulfone (named P­(PVSO 2 )) under different conditions (Scheme ).…”

“…Organic sulfur moieties can be selectively oxidized to sulfoxide and sulfone. , Herein, the oxidation behavior of PVS was investigated by cyclic voltammetry (CV) and was measured by a three-electrode system (reference electrode: Ag/AgCl; working electrode: glassy carbon; counter electrode: platinum wire) using tetrabutylammonium hexafluorophosphate as an electrolyte at room temperature in CH 2 Cl 2 . The concentration of PVS was 10 –2 mol L –1 .…”

“…Following these findings, it is interesting to investigate the possibility of constructing a responsive PC with an adjustable “ d ” value and “ n ” value at the same time. Herein, phenyl vinyl sulfide (PVS) was selected as a sulfur-functionalized monomer, which showed the ability to develop a high refractive index and selectively oxidative-responsive polymer. , At the same time, PVS could be polymerized by reversible addition–fragmentation chain transfer (RAFT) polymerization, which resulted in sulfur-containing polymers with controllable molecular weights and narrow molecular weight distributions. − Thus, a block copolymer of PVS and N,N ′-(dimethylamino) ethyl acrylate (DMAEA) was prepared by RAFT polymerization, which combined the oxidative-responsive moiety PVS and pH-responsive moiety DMAEA into one block copolymer. The responsive performance of the PC fabricated by block copolymers was investigated.…”

Nanoconfinement in miniemulsion increases reaction rates of thiol–ene photopolymerization and yields high molecular weight polymers

“…However, recent studies showed the formation of polymers with improved degrees of polymerization for thiol–ene products prepared in miniemulsion. 2,11–13 Such behavior could potentially be ascribed to a confinement effect similar to that observed during free-radical polymerization carried out in nanodispersed media, which leads to higher conversion rates of the monomers, and yield polymers with higher degrees of polymerization. 14,15 These observations demonstrate the need to investigate the mechanism of thiol–ene polymerization in nanoconfined systems to rationally design high molecular weight polythioethers and expand the range of applications of the resulting thiol–ene systems.…”