Glycol methacrylate embedding in histotechnology: factors which influence the evolution of heat during polymerization at room temperature

SUMMARY Benzoyl peroxide is widely applied as an initiator–accelerator system in combination with tertiary amines for the polymerization of water‐miscible methacrylates. However, this system is very sensitive to the ambient temperature and the evolution of exothermic heat is, especially at room temperature (293 K), difficult to control. Temperatures involved may increase beyond 373 K. A linear correlation between a graded series of benzoyl peroxide (0.2–1.0 g% benzoyl peroxide/glycol methacrylate) and the maximum temperature within the polymerizing plastic was established using a commercially‐available embedding system. Commercially‐available glycol methacrylates contain various concentrations of inhibitor in order to prevent spontaneous polymerization of the monomer. We tested a series of 200–300–400–800 ppm of the inhibitor hydroquinone and found a significant influence exerted upon the maximum temperature and the moment at which the maximum temperature was reached. Supplementary addition of inhibitors to the GMA monomer may effect a decrease of the maximum temperature within polymerizing GMA mixtures. Possibilities for standardizing the polymerization of glycol methacrylate by means of the benzoyl peroxide/tertiary amine initiator–accelerator system at room temperature are discussed.