Chemical Recycling and Physical Tuning of Necklace-Shaped Polydimethylsiloxanes Bearing Anthracene Dimer Units.

The problem of plastic waste in the environment calls for the development of new polymeric materials designed specifically for easy recycling at the end of their life cycle. Herein, we developed a green polymer system comprising a series of necklace-shaped polydimethylsiloxanes bearing anthracene dimer units. The polymers have low environmental impact and are easily recycled. Furthermore, their flexibility and glass transition temperatures are easy to control. These necklace-shaped inorganic polymers were synthesized by photopolymerizing (dimerizing) anthracene-terminated oligo-dimethylsiloxane monomers. A key achievement of the present work is the successful chemical recovery of the monomers from the polymers through thermal depolymerization, enabling monomer-polymer recycling. By applying equilibrium polymerization with base catalysts, we synthesized monomers with a controlled distributed chain length from monomers with a constant chain length. The necklace-shaped polymers synthesized from these randomized monomers had amorphous structures, and readily formed transparent films. It was possible to modulate the thermal and mechanical properties of the polymers by controlling the average chain length of the polydimethylsiloxane between the anthracene dimers. This investigation presents a method for the synthesis and cyclic utilization of polymer materials with a wide range of applications, including plastics and elastomers. This article is protected by copyright. All rights reserved.