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.