Process Analysis of PMMA-Based Dental Resins Residues Depolymerization: Optimization of Reaction Time and Temperature

This work aims to optimize the recovery of methyl methacrylate (MMA) by depolymerization polymethyl (PMMA) dental resins fragments/residues. In order pilot experiments at technical scale, PMMA scraps were submitted thermogravimetric analysis (TG/DTG/DTA). The conducted 345, 405, and 420 °C, atmospheric pressure, using a scale reactor 143 L. liquid phase products obtained subjected fractional distillation column 105 °C. physicochemical properties (density, kinematic viscosity, refractive index) reaction products, 345 determined experimentally. compositional 30, 40, 50, 60, 70, 80, 110 min, 405 130 100, 110, min GC-MS. morphology fragments before after was performed scanning electron microscopy (SEM) energy dispersive spectroscopy (EDX). show that yields 55.50%, 48.73%, 48.20% (wt.), respectively, showing first exponential decay behavior, decreasing with increasing temperature, while gas 31.69%, 36.60%, 40.13% growth, temperature. By comparing density, index pure MMA 20 °C those distillation, one may compute percent errors 1.41, 2.83, 0.14%, respectively. SEM showed all polymeric material carbonized. Oxygenated compounds including esters carboxylic acids, alcohols, ketones, aromatics detected chromatography/mass spectrometry (GC-MS) in atmosphere pressure. scraps, concentrations between 83.454 98.975% (area.) achieved. For experiments, phases purities above 98% time interval 30 80 min. However, 100 sharp decline observed. optimum operating conditions achieve high concentrations, as well elevated