Thermal degradation behaviors of polydimethylsiloxane-graft-poly(methyl methacrylate)

• We synthesized PDMS-g-PMMA by emulsion polymerization.
• The synthesized PDMS-g-PMMA possesses greatly improved thermal stability compared to PMMA.
• The degradation of PDMS chain happens only after PMMA chains decomposed mostly.
• Ea,av of thermal degradation of PMMA chain was larger than that of pure PMMA.

Polydimethylsiloxane-graft-poly(methyl methacrylate) (PDMS-g-PMMA) was synthesized by emulsion polymerization. Thermal degradation behaviors of PDMS-g-PMMA were studied by using thermogravimetric analysis-Fourier transform infrared spectroscopy (TGA-FTIR) and pyrolysis-gas chromatography–mass spectrometry (PY-GC–MS). It was found that a two-stage degradation happened due to PMMA graft chain and PDMS main chain, respectively, and the grafting ratio of PMMA can be calculated through the first-stage weight loss. The 5% weight loss temperature (T5%) of PDMS-g-PMMA increased with increasing PDMS contents. The apparent activation energy (Ea) of thermal degradation was evaluated by Kissinger–Akahira–Sunose method and the average value of Ea of PMMA chain in PDMS-g-PMMA was larger than that of pure PMMA.