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Synthesis of Sulfur-Containing Polymers Through Multicomponent Polymerizations
Yuzhang Huang1, Rongrong Hu1, and Ben Zhong Tang1
1South China University of Technology, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, Center for Aggregation-Induced Emission, No. 381 Wushan Road, Tianhe District, 510640, Guangzhou, China
2The Hong Kong University of Science & Technology, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Department of Chemistry, Clear Water Bay, Kowloon, Hong Kong, China
1.1 Introduction
Sulfur-containing polymers represent a group of popular advanced materials that have attracted much attention owing to their broad range of fascinating properties such as high refractivity [1], coordination with metal ion [2], self-healing property [3], dielectrical property [4], and unique electrochemical property [5]. The well-known sulfur-containing polymers include polythioethers [6], polythiophenes [7], polyoligosulfides [8], and vulcanized rubbers [9], which are generally prepared from classical thiol-ene/yne addition reactions [10], thiol-epoxy reaction [11], transition-metal catalyzed polycouplings [12], and other ring-opening reactions [13]. High sulfur-content materials with excellent optical properties were also reported to be prepared through inverse vulcanization with elemental sulfur [14,15]. However, the widely studied sulfur-containing polymers are still quite limited. Sulfur-containing polymers with new and complex structures remain rare, and their design and synthesis still face many challenges such as complicated and unstable monomer structures [16], poor solubility of polymers [17], chaotic product structures [18], etc. One effective approach is to develop new sulfur-containing polymer structures based on the exploration of new synthetic methodologies.
Multicomponent polymerizations (MCPs) as emerging polymer synthetic approaches combine three or more monomers in a one-pot reaction to construct complex polymers with high efficiency, great structural diversity, high atom economy, and well-defined structures [19]. During the past decade, with the inspiration from the progress in organic multicomponent reactions (MCRs), great effort has been made by polymer chemists to solve the problems regarding polymer solubility, structural regularity, narrow monomer scope, low conversion, molecular weight control, inhibition of side reactions, sequence control and topological control of the structures, and so on, and a series of efficient MCPs have been developed [20]. For example, the three-component Passerini polymerization of dialdehyde, dicarboxylic acids, and isocyanides was reported to access a class of polyesters [21]. Different combinations of various monomers were also applied to obtain sequence-regulated poly(ester-amine)s and hyperbranched polymers [22,23]. Many other MCPs such as Ugi four-component polymerizations [24], Biginelli polymerizations [25], Kabachnik–Fields polymerizations [26], alkyne, aldehyde, and amine A3-polycouplings [27], and a group of alkyne-based MCPs were reported [28–32]. Moreover, through diversity-oriented synthesis from different combinations of multiple types of monomers [33,34], MCPs can easily afford libraries of polymer materials with structural similarities.
Recently, MCPs prove to be powerful and popular tools for the construction of sulfur-containing polymers with unique structures and functionalities. The sulfur-related MCPs have been developed rapidly nowadays, and their recent progress will be summarized in this chapter. With their rich chemical properties and high reactivity, sulfur-containin...
