ADMET copolymerization

Another example of the flexibility of ADMET is the demonstration of successful polymerization of o /v-telechelic diene carbosilane macromonomers.45 The synthesis of macromonomer 30 is achieved using catalyst 23 and copolymerized with a rigid small-molecule diene, 4,4/-di-trans-l-propenylbiphenyl (Fig. 8.17). 

The slower, more controlled hydrolysis of silicon-methoxy bonds enables the synthesis of a material diat is processable and extremely tough, yet flexible, with the degree of flexibility a direct result of the molar feed ratio of die two monomers since both are incorporated equally in the ADMET copolymerization. Therefore, a series of materials can be made where the properties are adjusted... 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Sometimes it is possible to make a copolymer from deca-1,9-diene and a second diene that will not itself undergo ADMET polymerization, for example with divinyldimethylsilane260 or with p-dipropenylbenzene269. In other cases the second diene refuses to copolymerize but instead undergoes RCM this is so with (CH2 =CHCH2CMe2)2CO as the second diene234. 

There are several ways of using the olefin metathesis reaction to generate copolymers. Occasional reference has been made earlier to the formation of copolymers. Here we give further illustrations. For the ADMET copolymerization of linear dienes, see Section VII.C. 

The proposed idea that metal alkyhdene complexes are be able to catalyze olefin metathesis was confirmed in 1980 [8] and consolidated in 1986 by Schrock with the development of the first well-characterized, highly active, neutral tungsten (Cl, Fig. 3) [9] and molybdenum (C2) [10] alkylidene complexes. These complexes were able to catalyze both the metathesis of different olefins and the ROMP of functionalized norbomene to polynorbomene with low polydispersities [11]. Moreover, these catalysts were used by Wagener and coworkers to perform the first quantitative ADMET polymerization [12] and copolymerization [13] of 1,5-hexadiene and 1,9-decadiene. However, the low stability of these catalysts in... 

Ferulic acid, a phenolic acid that can be found in rapeseed cake, has been used in the synthesis of monomers for ADMET homo- and copolymerization with fatty acid-based a,co-dienes [139]. Homopolymerizations were performed in the presence of several ruthenium-based olefin metathesis catalysts (1 mol% and 80°C), although only C5, the Zhan catalyst, and catalyst M5i of the company Umicore were able to produce oligomers with Tgs around 7°C. The comonomers were prepared by epoxidation of methyl oleate and erucate followed by simultaneous ring opening and transesterification with allyl alcohol. Best results for the copolymerizations were obtained with the erucic acid-derived monomer, reaching a crystalline polymer (Tm — 24.9°C) with molecular weight over 13 kDa. 

Si l on admet que vjv peut se mettre sous la forme kx( — x), oil k est une constante caracteristique des interactions (Jenckel et Heusch, 1953), et que, d autre part, /,s= /2 (ce qui est le cas des copolymeres binaires dont les deux constituants ont sensiblement le meme Tg), on peut prevoir que la variation de T0tX passe par un maximum (k > 0) ou un minimum (k < 0) au voisinage de x = 0,5. Par suite de la valeur relativement petite du volume libre de relaxation, l effet du terme vjv peut etre important mime si k est tres petit (f 0,01). 

More industrial polyethylene copolymers were modeled using the same method of ADMET polymerization followed by hydrogenation using catalyst residue. Copolymers of ethylene-styrene, ethylene-vinyl chloride, and ethylene-acrylate were prepared to examine the effect of incorporation of available vinyl monomer feed stocks into polyethylene [81]. Previously prepared ADMET model copolymers include ethylene-co-carbon monoxide, ethylene-co-carbon dioxide, and ethylene-co-vinyl alcohol [82,83]. In most cases,these copolymers are unattainable by traditional chain polymerization chemistry, but a recent report has revealed a highly active Ni catalyst that can successfully copolymerize ethylene with some functionalized monomers [84]. Although catalyst advances are proving more and more useful in novel polymer synthesis, poor structure control and reactivity ratio considerations are still problematic in chain polymerization chemistry. 

ADMET polymerization has been used to integrate silicon into linear and network hydrocarbon polymers in an attempt to produce novel materials with enhanced thermal and mechanical stability. While ADMET has been used to produce copolymeric architectures unattainable through conventional methods, application of this polymerization to synthesis is feasible only if the silicon-based functionality does not inhibit metathesis. This research, initiated in the early 1990s by Wagener and colleagues, has shown that the silane and siloxane... 

The present book contains nine chapters focusing on the design of imine and phosphorylide catalyst structures, the preparation of cycloaliphatic materials, polar/ nonpolar monomer copolymerizations, organometallic polymerizations in aqueous media, and current frontiers in ROMP and ADMET processes. Exactly forty years after the Nobel Prize for Ziegler and Natta, we give a concise description of the state of the art in these fascinating and rapidly developing fields. The authors present, likewise, viewpoints from the forefront of both academia and industrial research, so that basic science and polymer applications are equally covered. 

Figure 6. Ester, urethane, poly-THF, and carbonate diene comonomers for ADMET copolymerization.

Siloxylene-vinylene-alkenylene Polymers via ADMET Copolymerization and Tandem ROIWCM Polymerization... 

High efficiency of the cross-metathesis of 1,9-decadiene and ROM/CM of cyclooctene with vinylsilanes points to a possibility of effective runs of the ADMET copolymerization of 1,9-decadiene [40] and tandem ROM/CM polymerization of cyclooctadiene [20], in both cases with divinylsilicon compounds. The reactions have proceeded according to Eq. 11, yielding polymeric material isolated and analyzed by GPC and NMR methods. 

Metathesis of 1,9-decadiene and cyclooctene with trialkoxy- and trisiloxy-substituted vinylsilanes in the presence of Grubbs catalyst, carried out in appropriate conditions, leads to the formation of bis(silyl)diene with a high yield. Similar processes performed with divinyl-substituted siloxane lead to the formation of silicon-containing polymers (via ADMET copolymerization and tandem ROM/CD polymerization), thus opening a new convenient route to synthesis of unsaturated organosilicon copolymers. 

ADMET copolymerization of 1,9-decadiene and 1,5-hexadiene [26] leading to perfectly random linear PBD-polyoctenamer copolymers was the first demonstration of the viability of this approach. The resulting copolymers contained comonomer ratios consistent with the monomer feed, and NMR analysis confirmed the random nature of the copolymer. Moreover, the same copolymers could be produced by the reaction of one comonomer with the homopolymer of the other comonomer for example, 1,9-decadiene with 1,4-PBD. This result further confirms the interchange reactions known to occur on the double bonds of the ADMET polymer backbone. 

Schrock s catalyst [Mo]2 has been used to polymerize thioether-containing dienes via ADMET [82]. In addition, di-5-hexenylsulfide was copolymerized with 1,9-decadiene to yield a random copolymer with anMj of 3.5 X lO gmol . An attempt was made to synthesize these polymers with [Ru]l however, a stable S-Ru chelate complex was formed, which resulted in catalyst inactivity (Figure 13.9) [37]. This was demonstrated with NMR spectroscopy, which revealed that a new alkylidene and free phosphine were formed during the reaction, which is consistent with the hypothesized chelation event. Additionally, a Ru-S bond is expected to be stronger than a Mo—S bond because of the sizes and polarizabilities of the two metals. 

While ketones are known to react, in some cases, in a Wittig-like manner with Schrock s [Mo]2 catalyst, ADMET polymerization does proceed for some ketone dienes [91], with optimum results for hindered ketones. Additionally, some of these monomers were copolymerized with 1,9-decadiene [92]. Unhindered ketones have been successfully polymerized with Grubbs [Rujl and [Ru]2 catalysts (Figure 13.12) [47, 84]. 

This study was followed by a series of papers that examined the effect of the distance between the pendant fluorine [96], chlorine [97], or bromine [98] atoms. Later, a series of ethylene/vinyl halide polymers containing fluorine, chlorine, and bromine were created via ADMET copolymerization of a halogen-containing (x,K)-diene and 1,9-decadiene [99]. Thermal analysis of these statistically random copolymers showed a distinct difference between their crystallization behavior and that of their compositionally matched precise analogs. The sharp melting... 

ADMET is capable of producing PE with specific sequences of monomer units, as well as random copolymers via copolymerization with 1,9-decadiene. The ability to precisely synthesize these polymers has opened the door to exploring the molecular origins of the material properties of these important polymers [135]. 

The copolymerization of ethylene with polar monomers is one potential method of improving various properties of PE [146, 147]. ADMET offers a method of synthesizing linear polymers identical to sequence-specific or random copolymers of ethylene and polar monomers with a variety of comonomer compositions. 

Copolymerization of conjugated and nonconjugated dienes has also been achieved with ADMET [63a]. Poly(acetylene-co-octenamer)s were produced by ADMET polymerization of mixtures of 2,4-hexadiene and 2,10-dodecadiene. NMR and UV spectra revealed that these polymers were blocky, with an average of 4-5 acetylene units per conjugated block. 

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