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Monomers butadiene

The preparation and characterization of 1,3-butadiene monomer is discussed extensively elsewhere (1 4) (see Butadiene). Butadiene monomer can be purified by a variety of techniques. The technique used depends on the source of the butadiene and on the polymerization technique to be employed. Emulsion polymerization, which is used to make amorphous /n j -l,4-polybutadiene (75% trans-1 4 , 5% kj -l,4 20% 1,2), is unaffected by impurities during polymerization. However, both anionic and Ziegler polymerizations, which are used to prepare kj -l,4-polybutadiene, mixed cis-1 4 and... [Pg.530]

SBR is produced by addition copolymerization of styrene and butadiene monomers in either emulsion or solution process. The styrene/butadiene ratio controls the glass transition temperature (To) of the copolymer and thus its stiffness. T ... [Pg.585]

Chemistry of polychloroprene rubber. Polychloroprene elastomers are produced by free-radical emulsion polymerization of the 2-chloro-1,3-butadiene monomer. The monomer is prepared by either addition of hydrogen chloride to monovinyl acetylene or by the vapour phase chlorination of butadiene at 290-300°C. This latter process was developed in 1960 and produces a mixture of 3,4-dichlorobut-l-ene and 1,4-dichlorobut-2-ene, which has to be dehydrochlorinated with alkali to produce chloroprene. [Pg.590]

Diene polymers refer to polymers synthesized from monomers that contain two carbon-carbon double bonds (i.e., diene monomers). Butadiene and isoprene are typical diene monomers (see Scheme 19.1). Butadiene monomers can link to each other in three ways to produce ds-1,4-polybutadiene, trans-l,4-polybutadi-ene and 1,2-polybutadiene, while isoprene monomers can link to each other in four ways. These dienes are the fundamental monomers which are used to synthesize most synthetic rubbers. Typical diene polymers include polyisoprene, polybutadiene and polychloroprene. Diene-based polymers usually refer to diene polymers as well as to those copolymers of which at least one monomer is a diene. They include various copolymers of diene monomers with other monomers, such as poly(butadiene-styrene) and nitrile butadiene rubbers. Except for natural polyisoprene, which is derived from the sap of the rubber tree, Hevea brasiliensis, all other diene-based polymers are prepared synthetically by polymerization methods. [Pg.547]

The polymerization of the butadiene monomers (3,4) can also be followed spectroscopically by the disappearance of the strong absorption of the monomers at 260 nm, whereas the absorption of the resulting poly-1,4-trans(butadiene)s is too small to be observed in a single monolayer. The polymers from the butadiene and methacryloyl lipids are probably better model membrane systems, because the polymer chains are still mobile and not excessively rigid as the polydiacetylenes. [Pg.220]

Synonyms Biethylene Bivinyl Butadiene Buta-1,3-diene a.y-Butadiene Butadiene monomer CCRIS 99 Divinyl EINECS 203-450-8 EINECS 271-039-0 Erythrene NCI-C50602 Pyrrol-ylene UN 1010 Vinylethylene. [Pg.199]

The JC-enriched butadiene samples were transferred and sealed in nmr tubes, along with the solvent and initiator, under a vacuum of about 10 torr. They were held at liquid nitrogen temperatures before warming to the reaction temperature. The non-enriched butadiene monomer was syringed from a hydrocarbon solution and injected through a rubber septum into an nmr tube containing solvent and initiator at liquid nitrogen temperature. The tube was then sealed under vacuum. [Pg.368]

The recent development of using hexane as a solvent for the preparation of SBS copolymers has been attempted even though the polystyryl, lithium is insoluble in this media, (,2k). Polystyryl lithium was dispersed in hexane using 1% of SBS rubber as a dispersing agent. The block copolymer tried as a dispersing agent retained the colloidal properties of poly-styrenyl lithium till the addition of the butadiene monomer. [Pg.418]

The compound (I) then reacts with additional butadiene monomer to form a polymer. [Pg.519]

In other words, the butadiene monomer reactivity significantly differs from isoprene but by a smaller factor than for a styrene-diene system. Nevertheless, the phenomenon of "reversal of... [Pg.530]

The diene polymerizations were generally allowed to proceed for 48 hours, which ensured quantitative conversion. In the case of butadiene, the reactor was cooled periodically to draw residual butadiene monomer into the solution from the void volume of the reactor. [Pg.561]

Potential exposure to butadiene can occur in the following industrial activities petroleum refining and related operations (production of C4 fractions containing butadiene, and production and distribution of gasoline), production of purified butadiene monomer, production of various butadiene-based rubber and plastics polymers and other derivatives, and manufacture of rubber and plastics products (tyres, hoses and a variety of moulded objects). [Pg.114]

Table 6. Eight-hour time-weighted average exposure levels in personal breathing zone samples at four butadiene monomer production facilities, United States, 1985... Table 6. Eight-hour time-weighted average exposure levels in personal breathing zone samples at four butadiene monomer production facilities, United States, 1985...
One cohort study of workers in the United States who manufactured 1,3-butadiene monomer showed a moderate and significant excess of lymphohaematopoietic cancers based on 42 deaths. Persons employed before 1950 were especially at increased risk, but there was no convincing association with a cumulative exposure score. A total of... [Pg.199]

Cowles, S.R., Tsai, S.P., Snyder, P.J. Ross, C.E. (1994) Mortality, morbidity, and haematological results from a cohort of long-term workers involved in 1,3-butadiene monomer production. Occup. environ. Med., 51, 323-329... [Pg.206]

Kelsey, K.T., Wiencke, J.K., Ward, J., Bechtold, W. Fajen, J. (1995) Sister-chromatid exchanges, glutathione S-transferase theta deletion and cytogenetic sensitivity to diepoxybutane in lymphocytes from butadiene monomer production workers. Mutat. Res., 335, 267-273... [Pg.211]

Krishnan, E.R.. Ungers, L.J.. Morelli-Schroth, PA. Fajen, J.M. (1987) Extent-of-exposure Study 1,3-Butadiene Monomer Production Industry, Cincinnati, OH, National Institute for Occupational Safety and Health... [Pg.212]

STEP 1 Polybutadiene rubber is formulated by feeding butadiene, water, an emulsifier, and catalyst into a glass-lined reactor. This is an exothermic reaction About 80% conversion is achieved in a period of about 50 hours. The residual butadiene monomer is recovered by steam-stripping and recycled. [Pg.1436]

Materials. Styrene and butadiene monomers were polymerization grade, available from Dow Chemical Company. Acrylic acid was a technical grade monomer from Dow Badische. The polymeriza-tion surfactant was sodium dodecyldiphenyl oxide sulfonate available from Dow. The polymerization initiator was sodium persulfate, and bromoform and carbon tetrachloride the chain transfer agents. [Pg.402]

A series of latex samples with varying stage ratios (LS-1 to LS-4) was prepared at 90°C by emulsion polymerizing styrene and butadiene monomer mixes (S/B/AA/CHBr3 59/40/1/0.5) in the pre-... [Pg.402]

Furthermore, Morton and co-workers (59,69) examined the PMR spectra of 1,3-butadiene monomers both in the presence and absence of polybutadieny(lithium in order to determine whether the diene protons of the monomer are shifted by interaction with the polymer lithium. No shifts were observed. Their finding indicates that if any complex between monomer and C—Li exists, it must be of a shorter lifetime than the NMR time scale. However, such a complex has been observed in the presence of a modifier such as DPE (31). [Pg.80]

In all cases, the formation of the higher telomers therefore seems to occur in multiples of C8 (i.e. coupling of an even number of butadiene monomers). The regioselectivity differences observed under the different circumstances and with the various catalyst systems are intriguing, and further investigations into the mechanistic details are warranted. Indeed, for some applications, e.g. as surfactant, aliphatic chains longer than C8 are required to get the proper balance in hydrophi-licity/hydrophobicity and molecular control over the process that allows one to achieve this is thus highly desired. [Pg.65]

Butadiene (Biethylene, Bivinyl, Butadiene Monomer, Divinyl,... [Pg.225]

Industrial polymerisation processes with the use of titanium-, cobalt- and nickel-based aluminium alkyl-activated Ziegler-Natta catalysts, which are employed for the manufacture of cis- 1,4-poly butadiene, involve a solution polymerisation in low-boiling aromatic hydrocarbons such as toluene or in a mixture of aromatic and aliphatic hydrocarbons such as n-heptane or cyclohexane. The polymerisation is carried out in an anhydrous hydrocarbon solvent system. The proper ratio of butadiene monomer and solvent is blended and then completely dried in the tower, followed by molecular sieves. The alkyla-luminium activator is added, the mixture is agitated and then the transition metal precatalyst is introduced. This blend then passes through a series of reactors in a cascade system in which highly exothermic polymerisation occurs. Therefore, the reaction vessels are cooled to slightly below room temperature. [Pg.319]


See other pages where Monomers butadiene is mentioned: [Pg.111]    [Pg.498]    [Pg.500]    [Pg.500]    [Pg.520]    [Pg.523]    [Pg.14]    [Pg.1028]    [Pg.875]    [Pg.166]    [Pg.262]    [Pg.265]    [Pg.313]    [Pg.367]    [Pg.374]    [Pg.518]    [Pg.523]    [Pg.116]    [Pg.128]    [Pg.272]    [Pg.101]    [Pg.98]    [Pg.14]    [Pg.58]    [Pg.404]    [Pg.64]    [Pg.638]   
See also in sourсe #XX -- [ Pg.237 ]

See also in sourсe #XX -- [ Pg.141 ]




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