Sodium polybutadiene

Sodium phosphate(s), 28 831-834, 29 18 carbon dioxide by-product of manufacture, 4 810 economic aspects of, 28 860 uses for, 28 833-834 Sodium polybutadiene, 9 555, 556 Sodium polymetaphosphate, 8 416 Sodium polyphosphates, 9 16 manufacture of, 28 858 Sodium polyphosphate glass, 28 851 Sodium polystyrene sulfonate cosmetic surfactant, 7 835t Sodium polysulfide(s), 23 640 in sodium production, 22 773 Sodium-potassium eutectic, 15 252... 

To obtain the absorbances at 910 and 967 cm. 1, it was necessary to correct the observed band intensities for the overlapping of adjacent bands. The band at 910 cm."1 for the vinyl group was corrected for the absorbance from the wing of the 967-cm."1 frarw-vinylene band,. and the latter band was corrected for the vinyl band at 995 cm. 1. The Lorentz band shape equation was used to calculate the absorbance in the wings, and in the thicker specimens, successive approximations were necessary. This treatment gave the four equations below, which yielded the concentrations of trans and vinyl groups for the emulsion and sodium polybutadienes listed in Table I. Implicit in these equations is the assumption that the absorptivities are independent of concentration. 

On the other hand, changes in the recipes of alkali metal polymerizations frequently make appreciable changes in the microstructures of the resultant polymers (2, 10, 12). Thus, sodium polybutadiene, or sodium polyisoprene, has a microstructure different from that of the corresponding potassium-catalyzed polymer. It also has been established that promoters or modifiers like dioxane or dimethoxytetraglycol affect the microstructure in these alkali metal catalyzed systems. One further example is afforded by the Alfin catalyst, which is apparently related to alkali metal catalysts but which gives a polybutadiene or polyisoprene with a microstructure very different from that of the corresponding alkali metal polymers. 

Sodium polybutadiene Emulsion polybutadiene Natural rubber Lithium polybutadiene... 

Sodium polybutadiene Emulsion polybutadiene Lithium polybutadiene Lithium polybutadiene Lithium butadiene-styrene, 89-11 LTP... 

The polymers in Table III catalyzed by sodium-mercury show structures identical with sodium polybutadienes. Because mercury, alone, does not catalyze the polymerization, these results should be compared with previous work (2) using sodium hydride which gave similar results. Both of these sets of experiments show merely that the crystalline structure of the sodium metal, or some other constitutive property, is not the deciding factor in the determination of polymer microstructure. 

The Young s bending modulus is a measure of the stiffness of a material—a higher value indicates a stiffer material. The sodium polybutadiene is, of course, considerably inferior to both of these polymers in this low temperature test. Table IV similarly illustrates the superiority, in compounded stocks, of lithium polybutadiene in low temperature shear recovery tests, also a measure of cold properties of a rubber. In this test the relative superiority of the lithium polymers to the emulsion and sodium polymer is even greater than that in the former test. 

PB(SKB) NR SKB=sodium polybutadiene rubber dilato-metric Tg results 32... 

In the late 1920s Bayer Company began reevaluating the emulsion polymerisation process of polybutadiene as an improvement over their Buna technology, which was based on sodium as a catalyst. Incorporation of styrene (qv) as a comonomer produced a superior polymer compared to polybutadiene. The product Buna S was the precursor of the single largest-volume polymer produced in the 1990s, emulsion styrene—butadiene mbber... 

The process of anionic polymerisation was first used some 60 or more years ago in the sodium-catalysed production of polybutadiene (Buna Rubbers). Typical catalysts include alkali metals, alkali metal alkyls and sodium naphthalene, and these may be used for opening either a double bond or a ring structure to bring about polymerisation. Although the process is not of major importance with the production of plastics materials, it is very important in the production of synthetic rubbers. In addition the method has certain special features that make it of particular interest. 

Polybutadiene was first prepared in the early years of the 20th century by such methods as sodium-catalysed polymerisation of butadiene. However, the polymers produced by these methods and also by the later free-radical emulsion polymerisation techniques did not possess the properties which made them desirable rubbers. With the development of the Ziegler-Natta catalyst systems in the 1950s, it was possible to produce polymers with a controlled stereo regularity, some of which had useful properties as elastomers. 

Buna [Butadien natrium] The name has been used for the product, the process, and the company VEB Chemische Werke Buna. A process for making a range of synthetic rubbers from butadiene, developed by IG Farbenindustrie in Leverkusen, Germany, in the late 1920s. Sodium was used initially as the polymerization catalyst, hence the name. Buna S was a copolymer of butadiene with styrene Buna N a copolymer with acrylonitrile. The product was first introduced to the pubhc at the Berlin Motor Show in 1936. Today, the trade name Buna CB is used for a polybutadiene rubber made by Bunawerke Hiils using a Ziegler-Natta type process. German Patent 570, 980. 

These efforts coupled with the much earlier work on sodium and lithium initiated polymerizations led to an appreciation of the stereospecificity of the alkyllithium initiators for diene polymerization both industrially and academically. Polymerization of isoprene to a high cis polyisoprene with butyllithium is well known and the details have been well documented 2 Control over polybutadiene structure has also been demonstrated. This report attempts to survey the unique features of anionic polymerization with an emphasis on the chemistry and its commercial applications and is not intended as a comprehensive review. 

Richardson and Sacher (41) showed that the anionic polymerization of butadiene with ethyllithium in THF produces mainly 1.2 structure in the polybutadiene. Roha (2) reviewed the typical anionic polymerization of butadiene to polymers containing 1.2 structure by catalysts such as alkyl sodium and alkyl potassium. Sodium naphthalene with THF produces 88% 1,2 polybutadiene (42). 

Reed 332) has reported that reaction of ethylene oxide with the a,(a-dilithiumpoly-butadiene in predominantly hydrocarbon media (some residual ether from the dilithium initiator preparation was present) produced telechelic polybutadienes with hydroxyl functionalities (determined by infrared spectroscopy) of 2.0 + 0.1 in most cases. A recent report by Morton, et al.146) confirms the efficiency of the ethylene oxide termination reaction for a,ta-dilithiumpolyisoprene functionalities of 1.99, 1.92 and 2.0j were reported (determined by titration using Method B of ASTM method E222-66). It should be noted, however, that term of a, co-dilithium-polymers with ethylene oxide resulted in gel formation which required 1-4 days for completion. In general, epoxides are not polymerized by lithium bases 333,334), presumably because of the unreactivity of the strongly associated lithium alkoxides641 which are formed. With counter ions such as sodium or potassium, reaction of the polymeric anions with ethylene oxide will effect polymerization to form block copolymers (Eq. (80) 334 336>). 

The mixture of methotrexate sodium with cytarabine, fluorouracil, hydrocortisone sodium, and prednisolone sodium phosphate produces precipitate upon storage, although it is not observed immediately. A concentration-dependent photodegradation was reported for methotrexate and considered high in the presence of bicarbonate ions and unprotected polybutadiene tubings.226 Methotrexate wastes may be disposed of by oxidation with potassium permanganate and sulfuric acid or by oxidation with aqueous alkaline hypochlorite. 

Using Alfin catalysts, butadiene polymers were already obtained in the 1940s. The Alfin catalytic system consists of three components (formed in statu nascendi from alkyl chloride, metallic sodium, alcohol and olefin) sodium salt of secondary alcohol (e.g. sodium isopropoxide), alkenylsodium (e.g. allyl-sodium) and finely dispersed sodium chloride (the name Alfin originates from a/cohol + olefin) [2,3], Since the molecular weight of polybutadiene obtained with Alfin catalysts is very high (it can reach a value of a few millions), 1,4-dihydronaphthalene is often added to the polymerisation system for the regulation of molecular weight [1],... 

A mixture of ammonium chloride and borax was one of the treatments of cellulosic fabrics reported by Gay-Lussac in 1821. Due to its low dehydration temperature and water solubility, sodium borates are only used as flame retardants in cellulose insulation (ground-up newspaper— see Sections 9.2.1.2 and 9.2.2.1), wood timber, textiles, urethane foam, and coatings. For example, a mixture of urethane (100 parts), borax (100 phr), and perlite (30phr) was claimed to provide flame-retardant urethane foam.8 Borax in conjunction with boric oxide, silica, ammonium chloride, and APB as ceramizing additives and volume builders, are claimed in a fire-protection coating based on polybutadiene and silicone microemulsion.9 Using a modified DIN 4102 test, the chipboard with the coating showed a loss of mass less than 1% and there was no pyrolysis of the wood sample. 

Again in polybutadiene, one finds sodium, potassium, rubidium and cesium giving polybutadienes fairly similar in structure varying from 35% 1,4 for sodium to 55% 1,4 for potassium and the 1,4 fraction varying from 71 to 85% trans. The trans-1,4 content is significantly lower than was observed in the case of polyisoprene. Again lithium is far removed from the other alkali metals, but in this instance the percentage 1,4 is now 85%, and of this 1,4 fraction only 40% is cis. The extreme stereospecificity which one finds in the isoprene case is not so pronounced with butadiene. 

A few other pertinent observations have been made. Although the effect of temperature on structure in the case of sodium or potassium metal polymerized butadiene was shown to lead to the gradual approach to a nearly random mixture between 0 and 45° (41,32), in the case of phenyllithium in tetrahydrofuran there is observed only a few percent difference between — 78° and + 100° (76). Furthermore, the use of lithium, n-butyllithium, n-amyllithium or isoamyllithium produces polyisoprene of the same microstructure in tetrahydrofuran (77). Kuntz (34) found that polybutadiene prepared with n-butyllithium in... 

Development of polybutadiene, polychloroprene and especially copolymers of butadiene andstyrene, as best replacements for natural rubber for tire-applications. Sodium used as catalyst Ring-opening polycondensation of caprolactam discovered by Schlack Formulation of the well-known Mark-Houwink equation for the viscometric determination of the molecular weight (mass)... 

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