Free-Radical Polymerization of Acrylic Acid under Extreme Reaction Conditions Mimicking Deep-Sea Hydrothermal Vents

Free-radical polymerization with a thermochemical initiator, which usually takes hours to complete, was dramatically accelerated under reaction conditions mimicking the deep-sea hydrothermal vents, where reaction mixtures were only briefly exposed to ultrahigh temperatures under pressure. In tests using acrylic acid and potassium persulfate, poly­(acrylic acid) (<i>M</i><sub>n</sub> = 2.1 × 10<sup>4</sup>, <i>Đ</i> = 2.73) was obtained in 5.2 s with the monomer conversion of 60.3% in water at 200 °C and 25 MPa without using any catalysts. The process that we call heat-shock-induced polymerization may pave the way for an entirely new strategy in reaction engineering for developing extremely fast, green, and scalable processes for polymer synthesis.