Methyl methacrylate transfer catalyzed

Ruthenium(II)-NHC systems ean be used for atom transfer radical polymerization (ATRP). Generally, similar results as for the analogous phosphine complexes are obtained. For the ATRP of styrene and methyl methacrylate (MMA) [(NHC)2peBr2] was found to rival copper(I)-based systems and to yield poly (MMA) with low polydispersities. Polymerizations based on olefin metathesis that are catalyzed by ruthenium-NHC complexes are discussed separately vide supra). 

Block copolymers can be produced from terminally borane-containing polyolefins. These borane-containing POs can be synthesized by the metallocene-catalyzed (co)polymerization of olefin(s) monomer with 9-BBN as a chain transfer agent or by the metallocene catalyzed copolymerization of olefins with allyl-9-BBN [55,56], as referred to above. Alternatively, borane-containing POs were prepared by hydroboration of terminally unsaturated PO, for instance, terminally vinyl PE and terminally vinylidene PP [33-35,57]. Such method could produce diblock copolymers, such as polyethylene-block-poly(methyl methacrylate) (PE-fo-PMMA), polypropylene-foZock-poly(methyl methacrylate) (PP-fc-PMMA), polypropylene-foZock-poly(butyl methacrylate) (PP-fc-PBMA), and PP-fc-PS. 

Peeters et al. combined the enantioselective eROP of 4-methyl-e-caprolactone (4-MeCL) with controlled atom transfer radical polymerization (ATRP) of methyl methacrylate (Scheme 11.17) [58]. It was found that the addition of Ni(PPh3)4 inhibited Novozym 435 and at the same time catalyzed the ATRP reaction. On the other hand, Novozym 435 did not interfere with the ATRP of methyl methacrylate. As a result the sequence of the reaction was important first the enantioselective eROP of 4-MeCL was conducted at low temperature to have a high enantioselectivity until the conversion was around 50%. Then, Ni(PPh3)4 and MM A were added and the temperature was raised to 80 °C to start up the ATRP reaction of MM A. After precipitation of the polymer to remove the unreacted (R)-4-MeCL, the chiral block copolymer (Mn= llkgmoT1 and 17 kg mol 1) was... 

Among these reactions, the Cu(l)-catalyzed azide-alkyne cycloaddition (CuAAC) is the most widely used. This reaction has been implemented for the preparation of segmented block copolymers from polymerizable monomers by different mechanisms. For example, Opsteen and van Hest [22] successfully prepared poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA) and PEO-b-PSt by using azide and alkyne end-functionalized homopolymers as the click reaction components (Scheme 11.2). Here, PEO, PSt, and PMMA homopolymers were obtained via living anionic ring-opening polymerization (AROP), atom transfer radical polymerization (ATRP), and postmodification reactions. Several research groups have demonstrated the combination of different polymerization techniques via CuAAC click chemistry, in the synthesis of poly(e-caprolactone)-b-poly(vinyl alcohol) (PCL-b-PVA)... 

Materials. The ultraviolet initiator Darocur 1173 (2-hydroxy-2-methyl-l-phenyl-propan-1-one) was purchased from EM Science and was used as received. Dimethylacrylamide (DMA), methacryloyl chloride (MC), allyloxytrimethylsilane and (tris(triphenylphosphine)rhodium)chloride were purchased from Aldrich Chemical Co. DMA and MC were distilled under nitrogen prior to use. 1,3-Tetramethyldisiloxane, methacryloylpropyltrichlorosilane, and 1,3-tetramethyldisiloxane platinum complex (2 % platinum in xylenes) were purchased from Gelest, The fluorinated allylic ether, allyloxy octafluoropentane, was prepared by the phase transfer catalyzed reaction of allyl bromide with octafluoropentanol using tetrabutylammonium hydrogen sulfate, tetrahydrofuran and 50% (w/w) NaOH (11). The fluorinated side-chain methacrylate end-capped siloxane (FSi) was prepared according to a literature procedure. All other solvents and reagents were used as received. 

---