Diene, conjugated polymers

Analyses of polymer microstructures do not allow these possibilities to be unambiguously distinguished, However, EPR experiments demonstrate that radicals add exclusively to one of the terminal methylenes.87 

When used in conjunction with unsymmetrical dienes with substituents in the 2-position, the term tail addition has been used to refer to addition to the methylene remote from the substituent. Head addition then refers to addition to 

Tacticity is only a consideration for units formed by 1,2-addition. However, units formed by 1,4-addition may have a cm- or a Ira , v - e o n fi g ura t i on, 

In anionic and coordination polymerizations, reaction conditions can be chosen to yield polymers of specific microstructurc. However, in radical polymerization while some sensitivity to reaction conditions has been reported, the product is typically a mixture of microstructures in which 1,4-addition is favored. Substitution at the 2-position (e.g. isoprene or chloroprene - Section 4.3.2.2) favors 1,4-addition and is attributed to the influence of steric factors. The reaction temperature does not affect the ratio of 1,2 1,4-addition but does influence the configuration of the double bond formed in 1,4-addition. Lower reaction temperatures favor tram-I,4-addition (Sections 4.3.2.1 and 4.3.2.2). 

Early work on the microstructurc of the diene polymers has been reviewed.1 While polymerizations of a large number of 2-substituted and 2,3-disubstituted dienes have been reported,88 little is known about the microstructure of diene polymers other than PB,89 polyisoprene,90 and polychloroprene.91 

When used in conjunction with unsymmetrical dienes with substituents in the 

4-addition and is attributed to the influence of steric factors. The reaction temperature does not affect the ratio of 1,2 1,4-addition but does influence the configuration of the double bond formed in 1,4-addition. Lower reaction temperatures favor 1,4-addition (Sections 4.3.2.1 and 4.3,2.2). 

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Conjugated diene polymers are modified and improved by copolymerizing them with other unsaturated compounds, such as acrylonitrile, H2C==CH—C=N. 

Title Modified Conjugated Diene Polymer, Polymerization Intitiator, Method of Producing the Same, and Rubber Composition... 

Modified Conjugated Diene Polymer, Polymerization Intitiator... 

Isomerism in conjugated diene polymers is a considerably more complex phenomenon than that encountered in a-olefin polymers. 

Bicyclic conjugated diene polymers were anionically prepared by Watanabe [ 1 ] using bicyclo[4.3.0]-2,9-nonadiene and bicyclo[4.3.0]-l,8-nonadiene and products used in high-performance resins. The polymer product of dicyclopenta-diene and 1,3-cyclohexadiene was also prepared by Oshima [2] and used in optical applications. 

Luo, S. Molybdenum-Based Catalyst Composition and Process for Controlling the Characteristics of Conjugated Diene Polymers. U.S. Patent 6,348,550, Feb 19, 2002 Bridgestone. 

Active anions have been used so far with epoxies, but epoxidation can be obtained by other means, as long as the polymer contains double bonds. It is possible to react an epoxidized conjugated diene polymer with a white filler, forming chemical bonds between rubber and silica without using a coupling... 

Although cyclic conjugated diene polymers are potentially fascinating materials, examples of these materials have been so far limited because of the following reasons ... 

One of the key technologies needed to make cyclic conjugated diene polymers useful is an expansion of monomer availability. Presently, neither 1,3-cycloheptadiene nor 1,3-cyclooctadiene has been coordinatively polymerized, even with highly active cationic Ni complexes. The polymerization of functionalized CHDs is, so far, limited to ANiTFA. In order to provide processability and functionality to cyclic conjugated diene polymers, these problems must be overcome. The progress of transition metal-catalyzed polymerization may make this possible in the near future. 

Anticorrosive Conjugated diene polymers Japan 8,132 1979 Ashai Chemical... 

Thermoplastic elastomers Conjugated diene polymers Netherlands 157,316 1978 Shell... 

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