A contaminant in commercial poly(methyl methacrylate) (PMMA), likely a surfactant used in its emulsion polymerization, significantly reduces the glass transition temperature of as-received PMMA (asr-PMMA) by acting as a plasticizer. Precipitation, the common purification method used in most PMMA research, may not be able to remove the contaminant efficiently, since it is highly dependent on the solvents and non-solvents used. In this research, we introduce a new purification method for the removal of the contaminant in asr-PMMA by first complexing asr-PMMA with urea or N,N'-dimethylurea and then removing both the small molecule and contaminant in the systerm by using methanol. Urea and N,N'-dimethylurea can separately form noncrystalline complexes with asr-PMMA. They each penetrate and reside between PMMA chains in the non-crystalline complexes and may accelerate transportation of methanol in and among PMMA chains, thus helping with the purification process. Our PMMA sample purified by the new purification method showed a 30° C higher Tg than the asr-PMMA plasticized by the contaminant.

Introduction of a new purification method for the removal of a contaminant in commercial PMMA by using urea and N,N'-dimethylurea

256th National Meeting (2018)

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