Non-linear Radical Additions-Coupling Polymerization of Monovinyl Monomers towards Polymer Networks: Theory, Tunability and Heritable Architecture

• Published in: Chinese journal of polymer science 2022-12, Vol.40 (12), p.1623-1630
• Main Authors: Ren, Li-Mei, Li, Cheng-Lin, Wang, Qi
• Format: Article
• Language: English
• Subjects: Addition polymerization; Carbon monoxide; Chain branching; Characterization and Evaluation of Materials; Chemical reactions; Chemical synthesis; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Continuity (mathematics); Coupling; Gelation; Industrial Chemistry/Chemical Engineering; Monomers; Polymer Sciences; Polymerization; Polymers; Polymethyl methacrylate; Research Article; Topology
• ISSN: 0256-7679; 1439-6203
• DOI: 10.1007/s10118-022-2788-z

Exploring new polymerization strategy for current available monomers is a big challenge in polymer science. Here we re-investigate radical polymerization of monovinyl monomer (MVM) initiated by uniform branched polyfunctional initiator (PFI), which is termed non-linear radical additions-coupling polymerization (NLRAsCP). In NLRAsCP, both addition and coupling reactions of radical contribute to the construction of the polymer chains, which leads to continuous growth of branch topology. Theoretical analysis of NLRAsCP predicts that the gelation is determined by the functionality of PFI ( a ), the extent of initiation of the PFI ( q ) and the termination factor of radical ( φ ). NLRAsCPs of styrene and methyl methacrylate promoted by Cu(0)/Me 6 TREN or Mn 2 (CO) 10 /visible light were conducted. After the cleavage of incorporated PFI fragment or junctions in the network, the network was transformed to linear chains having almost the same structure as segmental chains in the precursor network. This allows the reverse deducing the network structure from its cleaved products. It has been proven that NLRAsCP includes stepwise initiation of PFI, chain-growth of segmental chains and successive endlinking of macroradicals derived from PFI. The three parameters related to the gelation process, a, q and φ , were adjusted via binary PFI, the feed ratio of [Mn 2 (CO) 10 ]/[PFI] and addition of non-homopolymerizable comonomer respectively. The minimum values of a and q , and the minimum amount of comonomer required for gelation were determined, which can be applied to estimate φ of various macroradicals. NLRAsCP opens a general and facile strategy for synthesis of a variety of polymer networks with heritable architecture by one-pot polymerization of various MVMs.