Polybutadiene latex state

Fig. 38. Applications of the NMR-MOUSE to elastomer materials, (a) Values of T2 for a curing series of carbon-black filled NR. The measurements made with NMR-MOUSE are compared with the values obtained at 300 MHz in high homogeneous field, (b) T2 of a cross-link series of unfilled SBR with different sulfur contents, (c) T2 versus glass-transition temperature Tg of unfilled SBR by the CPMG and steady-state CPMG methods, (d) Normalized Hahn-echo decays for polybutadiene latex samples for small, medium, and large cross-link densities. Reproduced from Refs. 189 and 190, with permission from Rapra Technology.

Butadiene is used primarily in the production of synthetic rubbers, including styrene-butadiene rubber (SBR), polybutadiene nibber (BR), styrene-butadiene latex (SBL), chloroprene rubber (CR) and nitrile rubber (NR). Important plastics containing butadiene as a monomeric component are shock-resistant polystyrene, a two-phase system consisting of polystyrene and polybutadiene ABS polymers consisting of acrylonitrile, butadiene and styrene and a copolymer of methyl methacrylate, butadiene and styrene (MBS), which is used as a modifier for poly(vinyl chloride). It is also used as an intermediate in the production of chloroprene, adiponitrile and other basic petrochemicals. The worldwide use pattern for butadiene in 1981 was as follows (%) SBR + SBL, 56 BR, 22 CR, 6 NR, 4 ABS, 4 hexamethylenediamine, 4 other, 4. The use pattern for butadiene in the United States in 1995 was (%) SBR, 31 BR, 24 SBL, 13 CR, 4 ABS, 5 NR, 2 adiponitrile, 12 and other, 9 (Anon., 1996b). 

Figure 11.31 13C-NMR spectra of polybutadiene containing 80% gel (a) Solution measurement (10 w/v% CDC13 solution), (b) latex measurement (10 w/v % dry rubber content), and (c) solid state measurement [133]...

Meanwhile, however, a discovery was made which radically altered the approach to synthetic rubber production. In 1927, it was found that butadiene could be polymerized to a true latex in the presence of suitable emulsifiers and peroxide initiators. This discovery made possible the development of fast, efficient polymerization processes and eliminated many of the handling problems associated with bulk and solution methods. The polybutadienes obtained by emulsion polymerization, however, had disappointing properties and were difficult to process. Thus by about 1929 interest had shifted toward butadiene copolymers which had been found to have very promising properties. Butadiene copolymers, of course, formed the basis of the gigantic output of synthetic rubber which occurred in Germany and the United States during the Second World War but these developments are described in subsequent sections of this chapter. 

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