β Scribed by Samuel A. Fuqua; Robert M. Silverstein
No coin nor oath required. For personal study only.
This paper described the preparation and properties of a new class of silicone polyiners, A direct measure of ratios of copolymer the phenylene-perfluoroalkylene silicones. units in silicone copolymers was developed during this work.
Silicone elastomers have found applicability because of the wide temperature range over which they are useful. Elastomers can be produced which are flexible below -100Β°F. and yet retain useful properties-for a short period-at 600'F. This performance however has been achieved at some sacrifice of other properties. Compared with some elastomers that perform over a more limited temperature range, silicones are a t a disadvantage with regard to tensile strength, compression set, solubility, creep, and resistance to radiation damage.
Thermal degradation of silicone elastomers containing the (-Si-0-) backbone occurs mainly by a process of depolymerization in which the chain reverts to small rings, mainly trimers and tetramers. In order to minimize this tendency, the (Si-0-) repeating unit may be interrupted by rigid groups. This report is concerned with the preparation and properties of silicones I and I1 which contain phenylene groups separated by perfluoroalkylerie groups. Improved radiation and solvent resistance in addition to increased thermal stability might be predicted for these structures. Copolymers VI containing dimethylsiloxane units were also prepared.
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