Polybutadiene Rubber BR

Polybutadiene rubber (BR) is similar to natural rubber in its properties but it is more costly to process into intricate shapes than rubbers such as styrene butadiene rubber. Hence, it is essentially used as an additive in order to increase the tear resistance of other rubbers. 

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FIGURE 9.18 (continued) (b) Resilience measurements of elastomers. Samples of chlorobutyl rubber (CIIR), polybutadiene rubber (BR), and cross-linked recombinant resilin. (From Elvin, C.M., Carr, A.G., Huson, M.G., Maxwell, J.M., Pearson, R.D., Vuocolol, T., Liyou, N.E., Wong, D.C.C., Merritt, D.J., and Dixon, N.E., Nature, 437, 999, 2005.)... 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

The manufacture of polybutadiene rubber (BR), which is carried out mainly in solution processes using butyllithium or the Ziegler-Natta-type catalysts mentioned in Table 1, has some general features in common, despite the different catalyst systems [83]. The feed requirements for polymerization using Ziegler-Natta or... 

The presence of double bonds in the mainchain of a polymer increases the number of appearance forms of such a polymer. Well known examples of such systems are polybutadiene rubber (BR) and polyisoprene rubber (IR). BR for instance, can be polymerised into the following configurations ... 

Ivchenko et al. [1981] investigated the possibility of producing elastic films and coatings for synthetic leathers by introducing elastomers into PE (Table 11.9), followed by irradiation to increase their strength and heat resistance, and prevent ply separation (delamination). Six different elastomers (butyl rubber, HR, chlorinated-PE, CPE, chlorsulphonated-PE, CSR, polyisobutylene, PIB, and two polybutadiene rubbers, BR, were added to PE. Films were made on a roll mill at 105°C, and were then pressed at 130°C. The samples were irradiated at 20°C with electrons (dose rate = 0.4 kGy/s). 

There is a relatively large range of different types of rubbers that are used in different components in the food industry that can get in contact with the food. The most important of these are natural rubber (NR ds-l,4-polyisoprene), nitrile rubber (i.e., acrylonitrile-butadiene copolymer), ethylene-propylene rubber (EPR), rubbers of ethylene-propylene monomer (EPM) and EPDM, SBR, fluorocarbon rubber, silicone rubber, polybutadiene rubber (BR), polychloroprene rubber, and TPE. In addition, there is the use of rubber blends, i.e., blends of NR and N Rr with SBR [19]. 

World rubber usage of around 25.8 million metric tons is split between natural rubber, which constitutes about 43% of global consumption, and synthetic rubber, of which styrene-butadiene rubber (SBR) accounts for 21%. The balance of synthetic rubbers (36%) consists of polybutadiene rubber (BR) and a range of specialty polymers such as polyurethanes, halogenated polymers, silicones, and acrylates. Traditionally, the growth of synthetic and natural rubber consumption is virtually in line with the change in gross domestic product of, collectively. North America, Europe, Japan, China, and India. 

Polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polystyrene (PS), polymethylmethacrylate (PMMA) Ethylene-tetratluoro-ethylene (ETFE), tetrafluoroethylene/ hexafluoropropylene (THV), polyethylene (PE), polypropylene (PP) Epoxy resin (EP), polyester resin (UP), phenol resin (PF), resorcin resin (RF), polyurethane (PUR) Styrene-butadiene-rubber (SBR), polybutadiene-rubber (BR), ethylene-propylene-diene-rubber (EPDM)... 

Figure 3 Resilience measurements of cross-linked elastomers chlorobutyl rubber (CNR), polybutadiene rubber (BR), and cross-linked recl-resilin. Reproduced with permission from Elvin, C. M. Carr, A. G. Huson, M. G. etal. Nature 2005,437,999. Copyrighf 2005 Nature Publishing Group.

As discussed above, the amount of 1,2-addition in polybutadiene rubbers (BRs) can be varied from 8 up to 100% depending on the type of modifier and conditions used in organolithium polymerizations. This process versatility provides an important way to control 7 of BR and SBR rubbers. Figure 3 shows the relationship between increasing vinyl... 

While natural rubber began as the basis for automobile tires, synthetic rubber products replaced natural rubber - partly as a consequence of the rubber shortage of World War II. Synthetic rubber products include styrene-butadiene rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), nitrile rubber, neoprenes, polysulfides, polyacrylate rubber, and a host of other products with 65% of all SBR... 

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