Incorporation into silicone network

Incorporation of Ablative and Tethered Oils into Silicone Network... 

Chen et al. have developed an electrothermally actuated CNT-silicone composite [194]. They have been able to produce a maximal strain of 4.4% with an applied field of only 1.5 kV m by incorporating a CNT network into the silicone... 

Fortuniak, W. Mazerska, U. Chojnowski, J. Basinska, T. Slomkowski, S. Chehimi, M. M. Konopacka, A. Turecka, K. Werel, W., Polysiloxanes with Quaternary Ammonium Salt Biocidal Functions and Their Behavior When Incorporated into a Silicone Elastomer Network. J. Inorg. Organomet. Polym. 2011,21,576-589. 

The chains must be crosslinked to form a network (cf. Fig 7.16). In most elastomers containing double bonds, covalent bonds are introduced between chains. This can be done either with sulfur or polysulfide bonds (the well known sulfur vulcanisation of natural rubber is an example), or else by direct reactions between double bonds, initiated via decomposition of a peroxide additive into radicals. Double bonds already exist in the chemical structure of polyisoprene, polybutadiene and its copolymers. When this is not the case, as for silicones, ethylene-propylene copolymers and polyisobutylene, units are introduced by copolymerisation which have the property of conserving a double bond after incorporation into the chain. These double bonds can then be used for crosslinking. This is how Butyl rubber is made from polyisobutylene, by adding 2% isoprene. Butyl is a rubber with the remarkable property of being impermeable to air. It is used to line the interior of tyres with no inner tube. 

In this paper, we report two methods to control oil depletion from silicone foul release coatings ablative networks and tethered incompatible oils. The synthesis of ablative and tethered diphenyldimethylsiloxane oils, the incorporation of such oils into the silicone room temperature vulcanized (RTV) network and the foul release properties of RTV coatings containing the ablative and tethered oils are discussed. The residence time of radiolabeled diphenyldimethylsiloxane oils in silicone RTV topcoats is also addressed. Synthesis of the radiolabeled diphenyldimethylsiloxane oil and incorporation of the radiolabeled oil into the silicone network are discussed. In addition, the environmental partitioning of the radiolabeled oils in both freshwater and marine systems is presented with the material balance. 

The incorporation of ablative and tethered oils into the silicone topcoat of fouling release coatings is a desirable mechanism for slow, controlled release of the silicone oil from the RTV topcoat. Once incorporated into the silicone network, the hydrolytically unstable Si-O-C bond in the ablative oil (Figure 3) should slowly degrade in water. Conversely, the tethered oil is chemically bonded into the silicone network and one end (the non-miscible portion) should phase separate to the surface of the PDMS. Both ablative and tethered oils contain diphenyldimethylsiloxane functionality, based on previous studies of the free oil. The approach was to synthesize both ablative and tethered diphenyldimethylsiloxane copolymers, incorporate the copolymers into the RTV topcoat and then measure the foul release performance of the coatings. Both oils are shown below in Figure 3. 

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