Against the backdrop of problems such as environmental pollution and depletion of fossil resources, there is a demand for the development of technologies to recycle plastic waste. In particular, "chemical recycling," which regenerates waste plastics at the molecular level, is expected as an alternative to conventional recycling methods where products deteriorate during collection and reshaping. Poly(methyl methacrylate) (PMMA), widely used as transparent acrylic glass, can be decomposed by heating into methyl methacrylate (MMA), which is a monomer, but this required high temperatures of 400-450℃.
A research team led by Associate Professor Yasuhiro Kohsaka of Shinshu University developed modified acrylic glass that is easier to thermally decompose through copolymerization. The monomer composition was 95 mol% MMA and 5 mol% trityl methacrylate (TMA). When heated to 270℃ under reduced pressure, 95 percent of the MMA monomers were recovered. Furthermore, the team demonstrated that the same chemical recycling level could be achieved for commercial acrylic plates by applying this technology.
The modified acrylic glass can be synthesized using conventional bulk polymerization and suspension polymerization methods like PMMA and enables chemical recycling at low temperatures while maintaining molding processability and resin properties. This could lead to new recycling methods for acrylic glass.
(Article: Masanori Nakajo)
