Comparison of Surface and Bulk Properties of Pendant and Hybrid Fluorosilicones
Résumé
This chapter aims at supplying various strategies of fluorosilicones and the structure/property relationship. First, the "conventional" fluorosilicone are depicted and the most common one is poly(3,3,3-trifluoropropylmethylsiloxane) (PTFPMS) commercialized nowadays by Dow Corning. Then various ways have thus been employed to increase the number of fluorine atoms in the materials. One elegant way of preparing these is to simply introduce in the silicone chain, either as a pendant group or inside the backbone, perfluorinated groups of increasing size (typically C6 or more). Hence, "pendant silicones" are listed containing perfluorinated chains introduced as side groups of the silicone backbone whereas those bearying fluorine atoms into the main backbone are generally referred as "hybrid silicones". Additionally, polymers bearing fluorinated groups both in the main chain and as pendant groups in the class of hybrid copolymers complete that chapter. In each case, the properties of such fluoropolymers and their equivalent (crosslinked) elastomers are reviewed. Particularly, a thorough comparison of the above mentioned two classes of polymers in terms of mechanical, swelling or thermal properties is lacking, especially for the hybrid fluorosilicones. Intermediate conclusions will compare these above classes of polymers in regards with the considered property.