Trans-1,4-polymer

Melting point obtained by extrapolating to hypothetical pure trans polymer. ... 

Cyclopentene. After Eleuterio s early disclosure (10) of cyclopentene polymerization by ring-opening catalysis, Natta and co-workers (11) reported that trans polymer forms using WC16 catalyst and the cispolypentenamer forms using MoC15. The... 

The trans polymer is highly crystallizable. In contrast the cispolypentenamer is difficult to crystallize it requires 4 or 5 days at -78°C to develop crystallinity. 

An example of the use of 1,4-butanediol diglycidyl ether for the activation of soluble dex-tran polymers is given in Chapter 25, Section 2.3. One end of the fezs-epoxide reacts with the hydroxylic sugar residues of dextran to form ether linkages, which terminate in epoxy functionalities. The epoxides of the activated derivative then can be used to couple additional mol-ecules-containing nucleophilic groups to the dextran backbone. 

For ROMP of cyclopentene dominant 1,2 interactions will lead to trans polymer, but dominant 1,3 interactions will give an initial cis polymer. The latter seems to be the case in more crowded catalysts. 

We also mentioned Vestenamer 8012, a predominantly trans polymer of cyclooctene made with a WC16 based catalyst (Degussa-Hiils), used in blends and poly-norbomene made by a catalyst generated from RuC13 in t-BuOH in the presence of air (Norsorex by Atofina, a polymer with a very high molecular weight). 

When all of the double bonds in the polymer molecule have the same configuration, the result is two different ordered polymer structures—transtactic and cistactic. Figure 8-5 shows the structures of the completely cis and completely trans polymers of isoprene. The stereochemistry of these polymers is indicated in their names. For example, the trans polymer (IX) is named as trans-1,4-polyisoprene or poly( -l-methylbut-l-ene-l,4-diyl). The first name is the IUPAC-recommended trivial name the second name is the IUPAC structure-based (Sec. l-2c) [IUPAC, 1966, 1981, 1996],... 

Stereoisomerism in 1,4-poly-1,3-dienes results in significant differences in the properties of the cis and trans polymers. The trans isomer crystallizes to a greater extent as a result of higher molecular symmetry and has higher Tm and Tg values (Table 8-1). These trends are... 

Later, Tieke reported the UV- and y-irradiation polymerization of butadiene derivatives crystallized in perovskite-type layer structures [21,22]. He reported the solid-state polymerization of butadienes containing aminomethyl groups as pendant substituents that form layered perovskite halide salts to yield erythro-diisotactic 1,4-trans polymers. Interestingly, Tieke and his coworker determined the crystal structure of the polymerized compounds of some derivatives by X-ray diffraction [23,24]. From comparative X-ray studies of monomeric and polymeric crystals, a contraction of the lattice constant parallel to the polymer chain direction by approximately 8% is evident. Both the carboxylic acid and aminomethyl substituent groups are in an isotactic arrangement, resulting in diisotactic polymer chains. He also referred to the y-radiation polymerization of molecular crystals of the sorbic acid derivatives with a long alkyl chain as the N-substituent [25]. More recently, Schlitter and Beck reported the solid-state polymerization of lithium sorbate [26]. However, the details of topochemical polymerization of 1,3-diene monomers were not revealed until very recently. 

Figure 1 summarizes the chemical structures of the topochemically polymerizable 1,3-diene monomers providing stereoregular 1,4-trans polymer (Scheme 6) [ 16]. Most of the polymerizable monomers contain benzyl, naphthylmethyl, and long alkyl-chain substituents in their chemical structures. The (ZyZ)-, (E,Z)-, and ( , )-muconic and sorbic acids as well as the other diene carboxylic acids are used as the ester, amide, and ammonium derivatives. In contrast to this, the carboxylic acids themselves have crystal structures unfavorable for polymerization while they undergo [2-1-2] photodimerization, as has already been described in the preceding sections.

Scheme 6 Solid-state polymerization of 1,3-diene compounds providing 1,4-trans polymers...

This polymer is a hard plastic that occurs naturally as gutta-percha or balata. Since the trans isomer packs better than the cis isomer, it has a higher specific gravity, a higher degree of crystallinity, and a higher melting point (67 C) than the ds isomer of polyisoprene. The chemical and the solvent resistance of the trans polymer are simitar to those of the ds polymer. 

Initial yields for conversion to the trans-vinylene isomer can be derived by adding to the apparent yield the rate of destruction calculated from the initial concentration of trans-vinylene groups and the first-order rate constants determined for the amorphous trans polymer. The initial yield of trans-vinylene groups is 6.8 for gamma radiation and 4.4 for the reactor. The value for gamma radiation is similar to Golub s value of 7.2 for both gamma and electrons. 

The destruction of tram-vinylene groups in the crystalline high trans polymer had upper and lower G values of 22 and 11. There was little or... 

Polynorbomene the oldest polyalkenamer is manufactured by a method developed by CDF Chimie156 157 since 1976. Tungsten or rhodium catalysts are used to yield a highly trans polymer. This is capable of rapidly absorbing hydrocarbon oils and can be crosslinked to produce a very soft rubber. 

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