MM A polymerization

However, MM A polymerization photoinitiated by Re2 (CO)io (A = 365 nm) shows a long-lived aftereffect, persisting for several hours at 25°C after irradiation has... 

There is also a report on the use of a Re (I) complex (Re-2) in 1,2-dichloroethane at 50 °C, where the increase of molecular weights with conversion was observed in the MM A polymerization.143 Due to the absence of initiator, the solvent presumably serves as a supplier of the initiating radical species. The radical nature of the polymerization was suggested from the copolymerization behavior of MMA and styrene. 

Figure 5.3 Conversion-time profile for bulk MM A polymerization at 50 C with AIBN initiator illustrating the three conversion regimes. Data are taken from...

Matsuo, Y Mashima, K. Tani, K. Half-metalloeene tantalum complexes bearing methyl methacrylate (MMA) and 1,4-diaza-l,3-diene ligands as MM A polymerization catalysts. Angew. Chem., Int. Ed. Engl. 2001,40, 960-962. 

Fig. 11.6 Conversion versus time for MM A polymerization at 80 °C with 0.5 wt% of AIBN initiator in bulk and in native hydrophilic and silanized hydrophobic 13 nm-diameter CFG pores. Symbols are experimental data from three separate polymerizations. Solid lines are model calculations. After Refs. [63, 64]...

Variation of k-p with monomer concentration for MM A polymerizations in several ionic liquids at 40 °C. The dotted line serves as a visual guide. (Reprinted with permission from I. Woecht et al., Journal of Polymer Science Part. A Polymer Chemistry, 2008, 46(4), 1460. Copyright 2007 John Wiley and Sons.)... 

The studied amines such as TEA and TMEDA are among the simplest and cheapest amines, which is an attractive feature. The small PDI achievable even at high conversions would also be useful. Other examples of the MM A polymerizations are also listed in Table 7.5 (entries 3-7). 

We have prepared a copolymer-bearing amino side group and used it either alone or in combination with BP to initiate the photopolymerization of MM A [89]. The gel permeation chromatography (GPC) plot of PMMA initiated by the former system showed a bimodal distribution of molecular weight because both the radicals produced initiate polymerization as follows ... 

Misra et al. have utilized the ceric-amine redox system for grafting MM A onto wool [60] and gelatin [61], The graft yield was explained in terms of basicity, nu-cleophilicity, and steric requirements of amines. A complex of ceric ion and amine (AH) decomposes to generate free radical species, which produce additional active sites onto the polymeric backbone where grafting can occur. 

Tanaka et al,im observed that the adduct 71 from the monomeric MM A radicals adding to dimer was persistent and suggested that 71 may also act as a retarder or inhibitor of polymerization. However, the higher adducts 70 appear to be transient and no retardation beyond that expected from a reduced gel effect is observed.36... 

Kwon and coworkers have reported the use of diphenyl diselenide 2865"66 and a variety ofben/.ylic selenides (e.g. 29,67 615 30,69 3170 71 and 32K) as photoiniferters for polymerization of S, MM A and some derivatives. Very narrow dispersities were not obtained ( / Mn typically 2-2.5). However, it was possible to prepare... 

Triphenylinethyl terminated polymers (41) are formed in polymerizations conducted in the presence of triphenylmethyl thiol (40).9 5 Transfer constants for 40 are similar to other thiols (17.8 for S, 0.7 for MM A, compare Section 6.2.2.1). When the polymers (41) are heated in the presence of added monomer it is presumed that the S-CPh bond is cleaved and triphenylmethyl-mediated polymerization according to Scheme 9.11 can then ensue to yield chain extended or block polymers (42). 

Figure 4. Bulk polymerization of MM A at 22.5° C with AIBN Ri = 8.36 X 10 mol/L sec. Effect of conversion on propagation and termination rate constants (6).

Figure 1, Bulk polymerization of MM A at 45°C initiated by thermal decomposition of AIBN (5) (---) calculated from Equation 16, [I]o = 0,1 (O) 0,05 ( ) ...

Figure 5, Variation of the model parameters Cj (O) and Cb (X) u)ith temperature for the bulk free radical polymerization of MM A initiated by AIBN...

Figure 6, Arrhenius plot of A for polymerization of MM A initiated by AIBN using data of Figures 1-4...

Alkyl esters often show low reactivity for lipase-catalyzed transesterifications with alcohols. Therefore, it is difficult to obtain high molecular weight polyesters by lipase-catalyzed polycondensation of dialkyl esters with glycols. The molecular weight greatly improved by polymerization under vacuum to remove the formed alcohols, leading to a shift of equilibrium toward the product polymer the polyester with molecular weight of 2 x 10" was obtained by the lipase MM-catalyzed polymerization of sebacic acid and 1,4-butanediol in diphenyl ether or veratrole under reduced pressure. ... 

Figure 30. In situ measurements of the time evolution of the Cu K-edge when a platinum electrode coated with a polymeric film of poly (methylthiophene) is cathodically polarized in an aqueous solution containing 50 mM CuCl2. (From Ref. 105, with permission.)... 

Several rhodium(I) complexes have also been employed as ATRP catalysts, including Wilkinson s catalyst, (177),391 421 422 ancj complex (178).423 However, polymerizations with both compounds are not as well-controlled as the examples discussed above. In conjunction with an alkyl iodide initiator, the rhenium(V) complex (179) has been used to polymerize styrene in a living manner (Mw/Mn< 1.2).389 At 100 °C this catalyst is significantly faster than (160), and remains active even at 30 °C. A rhenium(I) catalyst has also been reported (180) which polymerizes MM A and styrene at 50 °C in 1,2-dichloroethane.424... 

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