Styrene-butadiene rubbers structural control

PREPARATION OF STYRENE/BUTADIENE RUBBERS OF CONTROLLED STRUCTURE... 

The uses of mercaptans in polymers fall into three major categories chain transfer agents, additives such as stabilizers against heat or UV light, and monomers that incorporate an alkylmercapto group into their structure. Mercaptans r-dodecyl, n-dododecyl, etc. are excellent chain transfer agents used to control molecular weight of several different kinds of polymers, styrene butadiene rubber, acrylonitrile-butadiene-styrene, polyacrylates, to name a few. " " ... 

Guo B, Chen F, Lei Y, Liu X, Wan J, Jia D (2009) Styrene-butadiene rubber/halloysite nanotubes nanocomposites modified by sorbic acid. Appl Surf Sci 255(16) 7329-7336 Gutowski KE, Broker GA, Willauer HD, Huddleston JG, Swatloski RP, Holbrey JD, Rogers RD (2003) Controlling the aqueous miscibility of ionic liquids aqueous biphasic systems of water-miscible ionic liquids and water-structuring salts for recycle, metathesis, and separations. J Am Chem Soc 125(22) 6632-6633... 

The solution polymerization system with anionic catalysts is best suited for the preparation of rubbers of controlled structure. The well-known structural control that is attainable in styrene/butadiene rubbers in such systems is given in Table 2. Of particular interest is... 

STRUCTURAL CONTROL IN SOLUTION STYRENE-BUTADIENE RUBBERS USING ANIONIC CATALYST SYSTEMS... 

The broad range of control of solution polymer structure and macrostructure of styrene-butadiene rubbers that is only possible using lithium catalysts was discussed in Section 2. We have seen how the microstructure of the butadiene units in the chain and comonomer sequence distribution can be controlled with the addition of polar modifiers and/or variations in pol5onerization process variables. Additionally, the unique control of macrostructure features and the new possibilities offered by reactive functional groups were discussed as part of the molecular engineering capabilities of solution anionic polymerizations. 

This paper will describe the ways in which the present needs in tire rubbers can be met by preparing butadiene-styrene solution polymers of controlled structure. This appears especially realizable today, as a result of two new classes of organo-alkaline earth polymerization initiators,... 

As it is well known [1] that the interlacial interaction role in multiphase systems, including polymer composites, is very great. In polymer composites such interactions (interfacial adhesion) absence results in sharp reduction of their reinforcement degree [2]. For polymer nanocomposites interfacial adhesion existence in the first place means the formation of interfacial regions, which are the same reinforcing element for these materials, as nanofiller actually [3], Proceeding from the said above, it is necessary to know the conditions and mechanisms of interfacial regions formation in polymer nanocomposites for their structure control. The present paper purpose is these mechanism definition and the indicated researeh is performed on the example of three particulate-filled nanocomposites on the basis of butadiene-styrene rubber. 

Table 2. Structural Control in Styrene/Butadiene Solution Rubbers Using Anionic Catalyst Systems...

Emulsion polymerization is the most important process for production of elastic polymers based on butadiene. Copolymers of butadiene with styrene and acrylonitrile have attained particular significance. Polymerized 2-chlorobutadiene is known as chloroprene rubber. Emulsion polymerization provides the advantage of running a low viscosity during the entire time of polymerization. Hence the temperature can easily be controlled. The polymerizate is formed as a latex similar to natural rubber latex. In this way the production of mixed lattices is relieved. The temperature of polymerization is usually 50°C. Low-temperature polymerization is carried out by the help of redox systems at a temperature of 5°C. This kind of polymerization leads to a higher amount of desired trans-1,4 structures instead of cis-1,4 structures. Chloroprene rubber from poly-2-chlorbutadiene is equally formed by emulsion polymerization. Chloroprene polymerizes considerably more rapidly than butadiene and isoprene. Especially in low-temperature polymerization emulsifiers must show good solubility and... 

The objective of this chapter is to provide a survey of the technological developments in solution rubbers prepared by homogeneous anionic polymerization. Emphasis will be on butadiene and styrene monomers, and catalyst systems based on organolithiums and their complexes with Lewis bases plus some unpubhshed work on alkahne earths from the authors laboratory. The rubbers thus obtained offer means for control of molecular structural features of polybutadiene and poly(butadiene-co-styrene) that directly relate to the functional properties of tyre rubbers. 

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