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Degradation Reactions in Silicone Polymers.

ADA050366

Publication Date	1976
Personal Author	Grassie, N.; Macfarlane, I. G.
Page Count	56
Abstract	This report is concerned with the preparation and thermal degradation of methyl and phenyl substituted siloxane polymers. There are three main experimental sections which are concerned respectively with poly(dimethyl-siloxane), poly(diphenylsiloxane) and poly(phenylmethylsiloxane). The volatile products of thermal degradation of poly(dimethylsiloxane) at temperatures from 200 C upwards, have been separated and estimated quantitatively using gas-liquid chromatography and shown to consist of cyclic trimer, tetramer, pentamer, hexamer, etc. in decreasing quantities. Infra-red spectral examination of the residual polymer suggests that crosslinking has occurred. At 160 C the molecular weight does not change, at 200 and 250 it increases to approximately double its initial value, while at 300, 350 and 400 C it increases initially but later decreases. The mechanism of thermal degradation of poly(dimethylsiloxane) is discussed in the light of these observations.
Keywords	Silicones Synthesis(Chemistry) Pyrolysis Methyl radicals Phenyl radicals Siloxanes Thermal stability Heat resistant plastics Thermogravimetric analysis
Source Agency	Non Paid ADAS
NTIS Subject Category	99C - Polymer Chemistry 71O - Plastics
Corporate Authors	Glasgow Univ (Scotland) Dept of Chemistry
Document Type	Technical Report
Title Note	Final rept. 1 Jul 73-30 Jun 75.
NTIS Issue Number	197810

Degradation Reactions in Silicone Polymers.

Degradation Reactions in Silicone Polymers.
ADA050366

Publication Date	1976
Personal Author	Grassie, N.; Macfarlane, I. G.
Page Count	56
Abstract	This report is concerned with the preparation and thermal degradation of methyl and phenyl substituted siloxane polymers. There are three main experimental sections which are concerned respectively with poly(dimethyl-siloxane), poly(diphenylsiloxane) and poly(phenylmethylsiloxane). The volatile products of thermal degradation of poly(dimethylsiloxane) at temperatures from 200 C upwards, have been separated and estimated quantitatively using gas-liquid chromatography and shown to consist of cyclic trimer, tetramer, pentamer, hexamer, etc. in decreasing quantities. Infra-red spectral examination of the residual polymer suggests that crosslinking has occurred. At 160 C the molecular weight does not change, at 200 and 250 it increases to approximately double its initial value, while at 300, 350 and 400 C it increases initially but later decreases. The mechanism of thermal degradation of poly(dimethylsiloxane) is discussed in the light of these observations.
Keywords	Silicones Synthesis(Chemistry) Pyrolysis Methyl radicals Phenyl radicals Siloxanes Thermal stability Heat resistant plastics Thermogravimetric analysis
Source Agency	Non Paid ADAS
NTIS Subject Category	99C - Polymer Chemistry 71O - Plastics
Corporate Authors	Glasgow Univ (Scotland) Dept of Chemistry
Document Type	Technical Report
Title Note	Final rept. 1 Jul 73-30 Jun 75.
NTIS Issue Number	197810