Programmable Compressing and Decompressing for Controllable Polymerization: The Case of Methyl Methacrylate

Conventionalhigh-pressure chemical reactions that are initiatedby manual compression or decompression face critical challenges inreproducibility, as different research groups often obtain differentresults. In this study, we developed a new high-pressure techniquetermed programmable compression and decompression (PCD) in order tosolve this problem. This versatile method allows us to arbitrarilyadjust the pressure loading modes, including the compression and decompressionrates, the amplitude, and the number of compression-decompressioncycles, to explore their effects on chemical reactions. Using thepolymerization of methyl methacrylate (MMA) as a model reaction, ourPCD technique shows that the characteristic of the pressure-inducedpolymerization (PIP) of MMA is "high-pressure initiation andlow-pressure polymerization". The effects of the initiationpressure, polymerization pressure, and holding time at low pressurewere confirmed by simple compression and decompression experiments.Furthermore, using the PCD technique, we set several pressure loadingmodes to explore the effects of the number of compression-decompressioncycles, amplitude, and rate on MMA polymerization. The results showthat the number of compression-decompression cycles and theamplitude significantly affect the conversion yield (CY). Our resultsdemonstrate that the PCD technique is a convenient method for controllinghigh-pressure reaction conditions and provide some inspiration forfuture high-pressure technology.