ISSN:
1432-1130
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract. Silicone resins can be used as polymeric precursors in the production of ceramic materials. Cohydrolysis of mixtures of trimethylchlorosilane, methyldichlorosilane, vinylmethyldichlorosilane and phenyltrichlorosilane leads to the formation of especially suitable polysiloxanes, but also low-molar mass siloxanes are formed as undesired by-products. The structures of these by-products have been elucidated. Vaporizable components of the matrix have been isolated by distillation, separated using gas chromatography and identified by mass spectrometry in EI (electron impact ionization) and CI (chemical ionization with isobutane) mode. The EI mass spectra of the siloxane oligomers with different numbers of Si-H, Si-phenyl and Si-vinyl groups show characteristic fragments like Me3Si+, ViMe2Si+, Vi2MeSi+, PhMe2Si+, and Ph2MeSi+, which give a first indication to the structure, but generally do not show molecular peaks. A reliable determination of the molar mass has been possible considering the CI-ions and CI-fragments [M+1]+, [M−1]+, [M−27]+ and [M−77]+, respectively. The compounds M2DPh,OH and M3TPh have been identified as main components of the investigated siloxane mixture. Besides, numerous linear compounds of the type M2(DH)n(DVi)m and M2TPh(DH)n(DVi)m M as well as cyclic ones of the structure [MTPh(DH)n(DVi)m] with n, m=0–3 have been indicated.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002169600004
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