Initiator-free photopolymerization of MMA in sealed systems: SEC/GPC data and molecular weight analysis
Description
This dataset contains raw and processed data obtained in the study of initiator-free photopolymerization of methyl methacrylate (MMA) under 395 nm irradiation in sealed systems containing air or CF₄. The dataset includes: - Raw SEC/GPC chromatograms (CSV format) - Processed chromatograms (PNG) - Molecular weight values (Mw, Đ) - MMA/air ratio series (2–11 mL MMA) - Control experiments under inert CF₄ atmosphere The data demonstrate that molecular weight is governed by the MMA/air volume ratio in sealed systems. Ultra-high molecular weight PMMA (~10⁷ g/mol) is obtained even in the presence of air when the monomer volume exceeds the gas phase volume. All experiments were performed without added initiators in static sealed vials under 395 nm irradiation.
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Steps to reproduce
Methyl methacrylate (MMA) was purified by vacuum distillation before use. Polymerization was carried out in sealed glass vials under static, non-stirred conditions. The MMA fill volume was varied from 2 to 11 mL in order to change the initial MMA/air ratio in the closed system. Irradiation was performed with a 395 nm LED source in a closed reflective chamber for 30 h at an average temperature of approximately 40 °C. A control series was performed under inert CF4 atmosphere under otherwise comparable conditions. After polymerization, the glass vial was broken and the polymer was recovered as a solid cylindrical sample. Samples were dried under vacuum at 100 °C to constant mass. Material for SEC/GPC analysis was consistently taken from the lower region of the cylinder to ensure strict comparability across the series. Molecular-weight distributions were determined by SEC/GPC with refractive-index detection using Agilent MIXED-C columns in THF at 40 °C and a flow rate of 1.0 mL/min. Molecular weights were calculated from external multipoint calibration based on Agilent polystyrene standards, including high-molecular-weight fractions. Signals eluting after 9.0 min were assigned to the solvent region and excluded from Mw and Đ calculations. The dataset contains raw chromatograms (CSV), processed chromatograms (PNG), and summary tables for the air and CF4 series.