Polymer octoate

Other Octoate Uses. Metal octoates are also used as driers in printing inks. Another appHcation of octoates includes the use of the aluminum salt to gel paint. Stannous, dibutyltin, and bismuth carboxylates find appHcation as catalysts in polyurethane foam appHcations in order to obtain a reaction efficiency suitable for industrial production. In polyurethane foam manufacture the relative rate of polymeriza tion and gas foaming reactions must be controlled so that the setting of the polymer coincides with the maximum expansion of the foam. 

Ring-opening polymerization was used to synthesize PTMC. The polymerization was carried out in evacuated and sealed glass ampoules with stannous octoate as a catalyst. The schematic reaction equations are shown in Schemes 8.7 and 8.8. The reaction time for aU homo- and copolymerizations were three days and the reaction temperature at 130 2°C. The obtained polymers were purified by dissolution in chloroform and precipitation in isopropanol. The precipitated polymers were collected, and washed with fresh isopropanol, and dried under reduced pressure at room temperamre until constant weight. 

Stannous octoate has the advantage of having been used to prepare polymers (Silastic, Capronor) for which substantial toxicological data are now available (6,48). Stannous octoate-initiated polymerization has been used to prepare copolymers of e-caprolactone with other lactones, including diglycolide, dilactide, 6-valerolactone, e-decalactone, and other alkyl-substituted e-caprolactones. Conducting... 

Hydrogenation was carried out with the assistance of an n-butyl lithium/cobalt octoate catalyst (6). It was necessary to determine the proper conditions for efficTent hydrogenation with minimal degradation (7). For the BIB polymer the Li/Co ratio used was 5/1 to obtain selective hydrogenation of the polybutadiene, while for the total hydrogenation of the BBB polymer, a ratio of 2.2/1 was satisfactory. NMR analysis showed better than 99% hydrogenation. 

The polymers were made according to procedures described in Ref. 15. A representative example is given here. A 1-liter round-bottom flask equipped with an overhead mechanical stirrer was flame dried under a vacuum to remove moisture from the interior surfaces of the vessel. When cool, the vacuum was released by the introduction of dry nitrogen gas. To the flask was added, in a dry nitrogen glovebox, 500.0 grams (3.469 moles) of pure L-lactide. Thai, 0.35 ml of a 0.33 molar catalyst solution (stannous octoate in toluene) containing 1.155 x 10 moles of catalyst was Current address Los Alamos National Laboratory, Los Alamos, NM 87544... 

Currently, tin(II) bis-(2-ethyUiexanoate), also referred as tin octoate, is the most widely used catalyst for the ROP of lactones. This popularity stems from its acceptance by the American Food and Drug Administration (FDA) for the formulation of polymer coatings in contact with food. Moreover, tin(II) bis-(2-ethyUiexanoate) is less sensitivity towards water and other protic impurities than aluminum alkoxides, which facilitates its use in the laboratory and in industry. 

Kowalski A, Libiszowski J, Majerska K, Duda A, Penczek S (2007) Kinetics and mechanism of E-caprolactone and LJ--lactide polymerization coinitiated with zinc octoate or aluminum acetylacetonate The next proofs for the general alkoxide mechanism and synthetic applications. Polymer 48 3952-3960... 

The liquid polymer is converted to the rubbery state by reagents that react with mercaptan (-SH) and side groups of the polymer segments by oxidation, addition or condensation to effect sulfide (-S-S-) bond formation. The oxidation reactions are exothermic and accelerated by an alkaline environment. The most commonly employed oxidizing agents which are suitable for curing liquid polymers are cobalt or manganese or lead octoate, p-quinonedioxime and di- or tri-nitrobenzene. Epoxy resin also reacts with liquid polysulfide polymers by addition in the presence of an aliphatic or aromatic amine and polyamide activator as shown in Equation 5.8 ... 

He XW et al. (1989) Poly(dimethylsiloxane)/poly(methyl methacrylate) interpenetrating polymer networks 1. Efficiency of stannous octoate as catalyst in the formation of poly(dimethylsiloxane) networks in methyl methacrylate. Polymer 30(2) 364-368... 

Due to the liquid state of the silicone prepolymer, silicone polymers are prepared as preformed sheets and tubing or any other shape by first mixing the drug with the silicone polymer and a catalyst (e.g., stannous octoate). Then, the mixture is cast as a sheet or in a mold followed by curing overnight. For example, Norplant is a set of flexible, closed cylindrical capsules (2.4 x 34 mm) of Silastic silicone polymer containing levonorgestrel for fertility control for 5 years. The capsules are inserted under the skin of the upper arm. 

Donors have been added to the cobalt catalysts used to polymerize butadiene (20). Cobalt chloride-pyridine complexes gave a soluble catalyst with AlEt2Cl which was effective for cis polymerization of butadiene, but at the low concentrations of pyridine employed (Al/Co/py = 1000/1/1 to 4), there was no effect on the polymer structure. However, it was observed that the molecular weight fell as the ratio of pyridine to cobalt was increased. Isopropyl ether in the cobalt octoate-methylaluminum sesquichloride catalyst had a similar effect, although at the highest ether concentrations (typical ratios employed were Al/Co/iPr20 = 160/1/3.5 to 8), a reduction in cis content and polymerization... 

Attempts to isolate the complex which forms trans polymer have been made, but no pure compounds have yet been isolated. From cobalt chloride, solid or liquid products were obtained which have variable composition. (Co = 5.7-15%, A1 = 5.2-10.6%, Cl = 20.6-26.2%, N = 4.5%, and replaceable ethyl groups 1.2-16.9%). It seems probable that in certain of these products some of the amine cobalt chloride complex is present without coordinated AlEt2Cl. The corresponding products from cobalt octoate have all undergone decomposition to a greater or lesser extent during isolation, but by suitably protecting the catalyst with other donors such as ethers or nonpolymerizable dienes, it may be possible to isolate a stable product. 

Thus, termination of oxazoline polymerization with potassium hydroxide gave hydroxy-terminated polymers, which in the presence of tin octoate were capable of initiating the anionic polymerization of -caprolac-tone [287] giving the corresponding block copolymer, acting as effective compatibiliser. 

Silanol-silane reaction. A is removal of H B is Si-O-Si crosslinked polymer tin octoate is the catalyst. 

Aliphatic prepolymerisation usually requires catalysts in addition to an elevated temperature. Typical conditions are 4h at 80°C-90°C with 20 ppm stannous octoate. One drawback of using catalysts in prepolymerisation is the promotion of unwanted side reactions and the reduction of shelf-life and stability, particularly with MDI polymers. 

Active catalysts for butadiene polymerization are obtained from aluminium alkyl halides and soluble Co and Co salts and complexes. The structure of the organic grouping attached to the cobalt is not important, but compounds most widely employed are acetylacetonates and carboxylic acid salts such as the octoate and naphthenate. The activity of the catalyst and structure of the polymer are affected by the groupings in the complex. Catalysts from aluminium trialkyls and cobalt salts other than halides are relatively unstable and give syndiotactic 1,2-polybutadiene. If halogens are present, e.g., from CoClj or CoBrj,... 

For a better understanding of the probe behavior in PDMS networks it was necessary to investigate the fluorescence behavior of a probe covalently bonded to a soluble polydimethylsiloxane chain. Therefore, a dialkoxysilane containing 4-piperidinobenzoic acid ester was allowed to react with a hydroxyl-terminated polydimethylsiloxane giving a soluble polymer with a covalently bonded probe at the main chain. This reaction occurs in the presence of Sn(II) octoate. The reaction scheme is drawn in Fig. 4. It was shown by GPC (UV detection) and NMR spectroscopy that the probe reacted with the hydroxyl groups of the polydimethylsiloxane chains. 

Examination of Figure 7 shows that stannous octoate strongly catalyzed the already rapid (3.0) ratio polymerization. The highest torque was realized in uncatalyzed Polymer 9 but prompt, substantial melt viscosity reduction, indicative of polymer degradation via shear-induced chain cleavage followed. Catalyzed Polymer 11 showed polymerization die-out at about 4 minutes of reaction time but no polymer degradation tendency is apparent even at these high torque and temperature levels. 

Figure 7. Thermoplastic urethane melt polymerization. Key X, Polymer 9 (natural) O, Polymer 11 (47 ppm stannous octoate).

Data Showing Stannous Octoate Catalyst Effect Polymers 9 11... 

---