Propagation butadiene polymerisation

Having made extensive studies of the behaviour of models of the propagation center of 1,3-diphenyl butadiene this monomer would be the most appropriate one to investigate. Unfortunately, it seems that it cannot be isolated because of extremely facile dimerisation via the Diels Alder reaction. A cursory examination has, however, been made of the polymerisation of... 

Rhodium salts such as Rh(N03)3.2H20 and RhCl3.3H20 exhibit catalytic activity for polymerisation of butadiene in protic solvents or aqueous emulsions and yield trans- 1,4-polybutadiene (>99%) [27,28,150-154]. Propagation active species are proved to be formed in such systems by the insertion of... 

The propagation reaction in conjugated diene polymerisation occurs by an analogous insertion, which has been demonstrated by 1H NMR analysis of the polymerisation of partially deuterated butadiene (CD2=CH—CH=CD2) with a simple re-crotyl derivative of nickel, [Ni(/73-C4DgH)I]2 [166],... 

Table 3.5 The value of rate constants for elementary stages of propagation reactions and their ratios in polymerisation of butadiene with the catalytic systems NdCl3-3TBP-Al(i-C,Hg)3 (I) and NdCl,-3TBP-Al(f-C Hg) H (II)...

The nomenclature poly (M1-6-M2) is used where Mj and M2 are the monomer names for example poly (styrene-b-butadiene). To make block copolymers, the polymer chains must have the ability to propagate [living polymers) when the first monomer is replaced by the second. In conventional addition polymerisation the chain termination and transfer processes make the lifetime of a growing polymer chain too short. Consequently, special ionic polymerisation catalysts were developed. A fixed number of di-anions such as [C6H5CHCH2CH2CHC6H5] are introduced into an inert solvent. These propagate from both ends if a suitable monomer is introduced. As there are no termination or transfer reactions, once the first monomer has been consumed, a second monomer can be introduced to produce a triblock copolymer such as styrene-butadiene-styrene. Each block has a precisely defined molecular weight. These materials undergo phase separation (Chapter 4) and act as thermoplastic rubbers. 

No. 16,1996, p.3665-73 ANIONIC POLYMERISATION OF STYRENE AND BUTADIENE INITIATED BYN-BUTYLLITHIUM IN ETHYLBENZENE DETERMINATION OF THE PROPAGATION RATE CONSTANTS USING RAMAN SPECTROSCOPY AND GEL PERMEATION CHROMATOGRAPHY... 

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