Controlled radical depolymerization of chlorine-capped PMMA via reversible activation of the terminal group by ruthenium catalyst. (November 2019)

• Record Type: Journal Article
• Authors: Sano, Yuki; Konishi, Takahiro; Sawamoto, Mitsuo; Ouchi, Makoto
• Is Part Of: European polymer journal. Volume 120(2019)
• Publication Date: 2019-11
• Subjects: Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2019.08.008
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: An unzipping-type depolymerization has been achieved for PMMA-Cl. A ruthenium catalyst afforded the depolymerization while keeping the narrow SEC curve. An evaporation of the generating monomer allowed further progress of depolymerization. Abstract: This paper deals with a preliminary study in controlled radical depolymerization, that is a unimodal polymer is converted into monomer while maintaining the narrow molecular weight distribution. Thus, our effort has been directed to unzipping-type depolymerization triggered by the reversible activation of the terminal group. An indenyl-based ruthenium catalyst afforded depolymerization of a chlorine-capped poly(methyl methacrylate) (PMMA-Cl) at relatively high temperature (>100 °C). Interestingly, the SEC curve shifted to lower molecular weight as the time proceeds, and the monomer, that is MMA, definitely generated and the amount almost corresponded to the decrease in molecular weight. The depolymerization was eventually saturated due to the equilibrium monomer concentration, but evaporation of the generating monomer followed by an addition of solvent and re-heating allowed further progress of depolymerization. We have thus demonstrated four consecutive depolymerizations via the evaporation methodology resulting in the unimodal SEC curve shift to lower molecular weight.