Dimethylsilanone Generation from Pyrolysis of Polysiloxanes Filled with Nanosized Silica and Ceria/Silica

Abstract

Temperature‐programmed desorption mass spectrometry (TPD MS) was used to study the pyrolysis of PDMS and its composites with nanosized silica and ceria/silica. The results suggest that the elusive organosilicon compound, dimethylsilanone, is generated from PDMS over a broad temperature range (in some cases starting at 70 °C). The presence of nano‐oxides catalyzes this process. Ions characteristic of the fragmentation of dimethylsilanone under electron ionization are assigned with the aid of DFT structure calculations. Possible reaction mechanisms for dimethylsilanone generation are discussed in the context of the calculated kinetic parameters. Observed accompanying products of PDMS pyrolysis, such as tetramethylcyclodisiloxane and hexamethylcyclotrisiloxane, indicate that multiple channels are involved in the dimethylsilanone release.

Silicone elastomers filled with rare earth oxides

“…Among the approaches, along with those in principle consisting of chemical modification, a path that offers many design opportunities is the incorporation of suitable active fillers to induce or enhance certain properties. It is known that the incorporation of a small amount of REO into polymers induces significant improvements in their properties, such as thermal stability, conductivity, hydrophobicity, surface or texture properties, etc [9].…”

“…CeO 2 proved to be an efficient reinforcing agent for natural rubber [17]. As additives to silicones, generally, in studies reported in literature [9,18], REO have been used together with silica (Ceria/Silica [9] or Ceria-Zirconia-Silica@PDMS [18]). There is a report in 1974 [19] about the thermostabilizing effect of rare-earth metal oxides on methylvinylsilicone rubbers.…”

“…Mechanical, dielectric, thermal, photoluminescent propertie, as well as moisture behaviour of the resulted composites, have been studied in comparison to the simple matrix considered as a reference in order to evaluate the effects of rare earth oxide addition on silicones. While the thermal degradation pattern of simple polysiloxane systems is relatively well studied and understood, the identification of chemical reactions occurring during the decomposition of polymers filled with nanoparticles is more complicated [9]. Therefore, the pyrolysis products of PDMS-REO composites prepared in this work were studied by TGA coupled with FTIR.…”

Mechanism on The Disproportionating Synthesis of Dichlorodimethyl‐ silane by ZSM‐5(5 T)@γ‐Al2O3 Series Core‐Shell Catalysts

“…In the silicone industry chain, monomers play a vital role, which preparation level marks the development level of the silicone industry . The amount of methylchlorosilanes accounts for more than 90% of the total monomers' yield, in which dimethyldichlorosilane((CH 3 ) 2 SiCl 2 , abbreviated as M2) is the most used and most important one . In order to promote the development of the silicone industry, it is important to disproportionate waste silanes into dimethyldichlorosilane.…”

Quantification of peroxynitric acid and peroxyacyl nitrates using an ethane-based thermal dissociation peroxy radical chemical amplification cavity ring-down spectrometer

“…Their barriers to dissociation have been reported (Davidson and Thompson, 1971) and are too large for decomposition to occur at the inlet temperatures used in this work. However, Kulyk et al (2016) …”