Acyclic monomers

What are the differences in the coordination of hydrocarbon unsaturated monomers and heteroatom-containing cyclic and acyclic monomers Give examples of catalysts and monomers. 

At the end of considerations concerning the coordination polymerisation of heteroatom-containing cyclic and acyclic monomers, it is obvious that future development (beyond carbon monoxide copolymerisations) is to be anticipated, especially concerning new catalytic processes, including both new... 

Name heteroatom-containing cyclic and acyclic monomers capable of undergoing coordination polymerisation. Indicate racemic monomers among them. 

TABLE 1. Ring-opening metathesis polymerization cyclic and acyclic monomers in preparing copolymers nsing catalyst l,3-dimesityl-4,5-dihydroimidazol-2-ylidene) benzylidene-tricyclopentylphosphine ruthenium(II) dichloride. 

Perfluorinated dioxole monomers have been used to prepare a series of amorphous fluoropolymers such as Teflon AF and Hyflon AD. A third amorphous fluoropo-lymer, Cytop contains perfluorotetrahydrofuran and perfluorotetrahydropyran rings, but is prepared in a cyclopolymerization process from an acyclic monomer. These amorphous fluoropolymers retain the outstanding chemical, thermal, and surface properties associated with perfluorinated polymers while also having unique electrical, optical, and solubility characteristics. 

Various types of polymerization reactions involving appropriate inorganic acyclic monomers have been quite effectively utilized for the preparation of polymers containing inorganic elements or inorganic groups. Some of... 

Acyclic monomers have also been found suitable for the preparation of poly(dichlorophosphazene). For example, heating the acyclic phosphazene derivative Cl3P=N-P(0)Cl2 leads to the elimination of P(0)Cl3 as the byproduct and affords the linear polymer, polydichlorophosphazene, [NPCl2]n (see Eq. 1.16) [34],... 

Anionic polymerization also can be used for preparing polyphos-phazenes from acyclic monomers. Thus, treatment of Me3SiNP(OCH2Cp3)3 with BU4NF leads to the formation of the polymer [NP(OCH2CF3)2]n(see Eq. 1.18) [32]. 

Acyclic C5. The C5 petroleum feed stream consists mainly of isoprene which is used to produce rubber. In a separate stream the linear C5 diolefin, piperylene (trans and cis), is isolated. Piperylene is the primary monomer in what are commonly termed simply C5 resins. Small amounts of other monomers such as isoprene and methyl-2-butene are also present. The latter serves as a chain terminator added to control molecular weight. Polymerization is cationic using Friedel-Crafts chemistry. Because most of the monomers are diolefins, residual backbone unsaturation is present, which can lead to some crosslinking and cyclization. Primarily, however, these are linear acyclic materials. Acyclic C5 resins are sometimes referred to as synthetic polyterpenes , because of their similar polarity. However, the cyclic structures within polyterpenes provide them with better solvency power and thus a broader range of compatibility than acyclic C5s. 

Aliphatic/aromatic. Copolymerization of aliphatic monomers (terpenes, cyclic C5, and acyclic C5) with the aromatic C9 petroleum stream is used to produce... 

Nearly all of the polymers produced by step-growth polymerization contain heteroatoms and/or aromatic rings in the backbone. One exception is polymers produced from acyclic diene metathesis (ADMET) polymerization.22 Hydrocarbon polymers with carbon-carbon double bonds are readily produced using ADMET polymerization techniques. Polyesters, polycarbonates, polyamides, and polyurethanes can be produced from aliphatic monomers with appropriate functional groups (Fig. 1.1). In these aliphatic polymers, the concentration of the linking groups (ester, carbonate, amide, or urethane) in the backbone greatly influences the physical properties. 

Wolfe and Wagener have developed main-chain boronate polymers (59) (Fig. 38) by the acyclic diene metathesis (ADMET) polymerization of symmetrical ,oj-dienes, containing both methyl- and phenyl-substituted boronate functionalities using Mo and Ru catalysts.84 The ring-opening metathesis polymerization (ROMP) of several norbornene monomers containing methyl- and phenyl-substituted boronates into... 

This process is quite unexpected for another reason. The cyclobutene ring is highly strained, making this monomer one of the most easily polymerized of all the cycloolefins. Thus, the variety of catalysts effective for cyclobutene polymerization is much broader than that effective for metathesis of low-strained cycloolefins and acyclic olefins (73). Therefore, the recovery of monomeric cyclobutene rather than its respective polymer is remarkable and indicates the lack of substantial metathesis activity in the above retrocarbenation system. 

The diverse steric course of the metathesis of cyclic vs. acyclic olefins poses a dilemma. It stands to reason that once a cycloolefin monomer... 

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