Improvement of thermal resistance of polydimethylsiloxanes with polymethylmethoxysiloxane as crosslinker

Synthesis and characterization of imide modified poly(dimethylsiloxane) with maleopimaric acid as raw material

“…These special performances allow silicones well suited for applications that experience large temperature swings and long service lifetimes, such as automotive engine sealants, damping material in aircraft and encapsulant for electronic devices [1]. However, polysiloxanes start to degrade around 200 8C, especially poly(dimethyl siloxane) undergoes dramatic thermal degradation above 300 8C [1,2].…”

“…These special performances allow silicones well suited for applications that experience large temperature swings and long service lifetimes, such as automotive engine sealants, damping material in aircraft and encapsulant for electronic devices [1]. However, polysiloxanes start to degrade around 200 8C, especially poly(dimethyl siloxane) undergoes dramatic thermal degradation above 300 8C [1,2]. Many efforts have been made to improve the high-temperature thermal stability of silicones, such as adding inorganic additive [2], increasing crosslink density [1] and incorporating rigid group (e.g., phenyl and imide heterocycle) [3,4].…”

“…However, polysiloxanes start to degrade around 200 8C, especially poly(dimethyl siloxane) undergoes dramatic thermal degradation above 300 8C [1,2]. Many efforts have been made to improve the high-temperature thermal stability of silicones, such as adding inorganic additive [2], increasing crosslink density [1] and incorporating rigid group (e.g., phenyl and imide heterocycle) [3,4]. The inorganic additives are not compatible with silicones, and the processing problems with blending technique still exist [1].…”

“…Many efforts have been made to improve the high-temperature thermal stability of silicones, such as adding inorganic additive [2], increasing crosslink density [1] and incorporating rigid group (e.g., phenyl and imide heterocycle) [3,4]. The inorganic additives are not compatible with silicones, and the processing problems with blending technique still exist [1]. The second method of increasing crosslink density with polymethylmethoxysiloxane as crosslinker is only applicable to silicones vulcanized by free radical polymerization.…”

“…The preparation scheme of MP-VMS was shown in Fig. 1 As a contrast, MR modified vinyl-containing silicone (MR-VMS) was prepared strictly according to the aforementioned process, except that MPA was replaced by MR. Common vinyl-containing silicone (C-VMS) was also prepared according to the aforementioned process, except that HAPMS and MPA were absent and the loading of D 4 was adjusted to 48.1 g. The NMR results of C-VMS are listed as following: 1 NMR analyses were conducted with a Bruker DRX-500 nuclear magnetic resonance spectrometer with tetramethylsilane as the internal standard. DSC was performed on a Perkin-Elmer Diamond instrument in flowing nitrogen gas.…”