Fluorosiloxane sealants for aviation industry

Improved synthesis and properties of hydroxyl‐terminated liquid fluorosilicone

“…Organopolysiloxanes having 3,3,3-trifluoropropyl groups bonded to the silicon atoms are widely used as the principal constituent of various kinds of silicone products by virtue of their unique properties such as low surface energy and excellent oil resistance, and thus it is a promising material for different commercial and military applications. [1][2][3][4][5][6][7][8][9][10][11] The introduction of F atom would increase the polarity of polysiloxane molecules, and thus the oil and fuel resistance properties of the silicone rubber could be well improved. 5,12 Fluorosilicone gums can be made into fluorosilicone rubbers of both heat cured, and roomtemperature vulcanizable varieties.…”

“…As shown in Scheme 1, the linear polymers are formed by the consumption of D 3 F (the chain propagation), while the unexpected cyclic by-products, D n F, are also formed simultaneously through the chain redistributions or the back-biting by chain ends of linear polymers (the chain depropagation) and a content as high as 8090 wt % has been proved at equilibrium. 9 This highly unsatisfactory result drives the organosilicon chemists to explore new methods to suppress the cyclics content for both scientific interest and industrial consideration. Veith et al 21 carried out the kinetic analysis of the polymerizations of D3F to determine the optimal polymerization conditions for the maximal yield of PTFPMS (85-90 wt %).…”

Reply to comment by Biemann and Bada on “Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars”

“…[ Mark , 1999]. In contrast, methylfluorosiloxanes are silicone elastomers that are normally used as O‐rings or sealants [ Donskoi and Baritko , 2007]. Their detection in the GC‐MS experiments implies that there was some degree of degradation of these polymers during the conduction of the Viking experiments; however, because these contaminants were detected, it does not imply that other trace compounds observe in the experiments at the same levels (e.g., CH 3 Cl and CH 2 Cl 2 ) should be classified as contamination.…”

Preparation and characterization of high molecular weight vinyl-containing poly[(3,3,3-trifluoropropyl)methylsiloxane

“…Poly[(3,3,3-trifluoropropyl)methylsiloxane] (PTFPMS) is resistant to oil, fuel, solvents, and extreme heat and cold [ [1] , [2] , [3] , [4] , [5] ]. It can be used as a sealing material for aviation and automotive fuel tanks [ [6] , [7] , [8] ]. Because PTFPMS has good film-forming properties, it can also be made into various coatings [ [9] , [10] , [11] ], such as release agents and protective layers.…”