A New Process for the Preparation of Highly Saturated Nitrile Rubber in Latex Form

ABSTRACT:The mechanism and the optimum conditions for the reduction of residual double bonds in styrene-butadiene rubber (SBR) latex by hydrogenating the polybutadiene in the latex form were studied. The hydrogenation involves a copper ion (II)-catalyzed procedure in which diimide hydrogenation agent is generated in situ at the surfaces of latex particles by a hydrazine/hydrogen peroxide redox system. The surface density of the copper ion in particle surfaces was found to be a crucially important parameter in controlling the degree of hydrogenation. The distribution of the double bonds in the latex particles after the hydrogenation was found to be dependent on the particle size and the extent of crosslinking in the particles.

Section: Location and Concentration Of Copper Ionmentioning

confidence: 99%

Section: Location and Concentration Of Copper Ionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hydrogenation of styrene-butadiene rubber (SBR) latexes

Daniels

Klein

et al. 1997

“…This type of emulsion may have potentially important applications for the coating industry. [22][23][24] In the following, two proHydrogenation Process cesses for the direct hydrogenation of NBR emulsion have been investigated and the results are All the reactions were carried out in a stainless steel autoclave. The NBR copolymer emulsion was presented.…”

Section: -29mentioning

confidence: 99%

Catalytic hydrogenation of nitrile-butadiene copolymer emulsion

Guo

Rempel

1997

Two processes have been developed for the selective hydrogenation of the C|C bonds in nitrile-butadiene rubber emulsions (NBR emulsions) in the presence of a number of RuCl 2 (PPh 3 ) 3 complex catalysts. One of the processes is carried out in a homogeneous system, in which an organic solvent, which can dissolve the NBR polymer and catalyst and which is compatible with the emulsion, is used. The other process is carried out in a heterogeneous system, in which an organic solvent which is capable of dissolving the catalyst and swelling the polymer particle but is not miscible with the aqueous emulsion phase, is used. In both processes, quantitative hydrogenation of the C|C bonds of the NBR emulsion is achieved in the presence of RuCl 2 (PPh 3 ) 3 . It is also found that the addition of certain types of additives can improve the activities of the Rubased catalysts.

Influence of styrene content on the hydrogenation of styrene-butadiene copolymer

Sarkar¹,

De²,

Bhowmick³

1999

A hydrogenated styrene-butadiene copolymer (HSBR) was prepared by a diimide reduction of SBR in the latex stage. The influence of the styrene content on various reaction parameters, namely, time, temperature, and concentration of the reactants and the catalyst was studied. A comparatively lower temperature, longer time, lesser amount of hydrogen peroxide, and higher amount of the catalyst are required to optimize the hydrogenation reactions of SBR with a higher styrene content. The diimide reduction of SBR is first order with respect to the olefinic substrate and the apparent activation energy increases with increase in the styrene level. All the hydrogenated copolymers were characterized with the help of IR, NMR, and DSC. The TGA data indicate a higher thermal stability of HSBR as compared to SBR in nitrogen, although an anomalous behavior is observed in air due to crosslinking and oxidation.