Silicon-containing styrenes

These foams can then be extended into the area of flame-retardant materials, where methyl oleate-polyesters were used as polyols in the synthesis of silicon-containing polyurethanes [89]. Despite not strictly being foams, methyl oleate, soybean and sunflower oils have also been investigated to produce semi-rigid flame retardant materials [90]. In this instance, they were brominated, acrylated and then radically copolymerized with styrene to form the polymeric material. 

Naghash, H. J. Hajati, F., Synthesis and Characterization of a Novel Silicone Containing Vinylic Macromonomer and Its Uses in the Preparation of Poly(silicone-co-styrene-co-butylacr ate) with Montmorfllonite Nanocomposite Emulsion. J. Appl. Polym. Sci. 2012,123,1227-1237. 

In 1975 Wacker-Chemie introduced silicones under the name of m-polymers. These are also room temperature curing liquid polymers which give rubbery materials on cross-linking and are available both as one- and two-component systems. Their particular feature is that they contain dispersions of copolymers such as those of styrene and n-butyl acrylate in the shape of rods or rice grains in the fluid silicone polymer. A small amount of the organic copolymer is also grafted onto the silicone backbone. 

Polystyrene itself is not used for endoprosthetic purposes and its application is accounted for only because of easy substitutions in benzene rings. The method was subsequently modified for heparinization of silicone and natural rubber, polyethylene, polypropylene, polyethylene terephthalate), and other polymers. Styrene was first grafted onto the polymers by y-radiation and then the above-described reaction was performed in the second step. All the polymers synthesized in this way contained sufficiently large amounts of immobilized heparin (2.8—15.7 ng/cm2) and displayed good thromboresistance when tested in vitro — recalcified blood was not clotted for several hours. 

A final example of the application of 13C NMR spectroscopy is taken from our work9 on copolymers of methacrylates and vinyl phenol which were synthesized using similar chemistry to that shown previously for the styrene-co-vinyl phenol copolymers. In Figure 7-48 are typical 13C NMR spectra of an ethyl methacrylate (EMA) copolymer containing 52 mole % EMA before (top) and after (bottom) deprotection. The absence of the NMR peaks at around 0 ppm (the two methyl carbons attached to silicon), 19 ppm (the tertiary carbon of the f-butyl group), and 26 ppm (the three methyl carbons on the f-butyl group) after desilylation, clearly indicates the absence of any residual f-butyldi-methylsilyl groups. 

Influence of the Length of the Paraffinic Chains. Lipopeptides with paraffinic chains containing 18 or 16 carbon atoms give with oils very difficult to emulsify (styrene, ricin oil, vaseline oil, silicon oil..) miniemulsions stable for more than 2 months. In contrast, lipopeptides with paraffinic chains containing 14 or 12 carbon atoms give miniemulsions stable for less than 20 days. 

A free flowing monomer, ethylene glycol dimethacrylate (EGD) stabilised with 0.1% hydroquinone is thickened with 0.0, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 14.0 and 16.0% of methyacrylate butadiene styrene (MBS). Two further samples of the same monomer are thickened with similar increasing concentrations of cellulose nitrate (CN) and silicone dioxide (SiCh) for comparison. An accurate weight of 10.0 g of each thickened monomer is dissolved in 25% n-propanol and 75% glacial acetic acid. Then 0.25 ml of 1000 ppm Zn metal stock standard solution is added to each mixture. These solutions are also spiked with 0.5 ml of 1000 ppm indium (In) metal as internal standard. All mixtures are diluted to mark with the 25% n-propanol/glacial acetic acid. The mixtures contain 2.5 ppm Zn and 5.0ppm In per ml. 

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