PMMA-grafted

The high-molecular weight was assigned to the PMMA grafted to the copolymer chains and the low-molecular weight to the PMMA initiated by the MMA radical (II). However, only one molecular weight distribution peak was observed for the PMMA initiated by the latter system, i.e., in combination with BP, which implies that only aminomethyl radicals are capable of initiating the polymerization. 

A radical initiator based on the oxidation adduct of an alkyl-9-BBN (47) has been utilized to produce poly(methylmethacrylate) (48) (Fig. 31) from methylmethacrylate monomer by a living anionic polymerization route that does not require the mediation of a metal catalyst. The relatively broad molecular weight distribution (PDI = (MJM ) 2.5) compared with those in living anionic polymerization cases was attributed to the slow initiation of the polymerization.69 A similar radical polymerization route aided by 47 was utilized in the synthesis of functionalized syndiotactic polystyrene (PS) polymers by the copolymerization of styrene.70 The borane groups in the functionalized syndiotactic polystyrenes were transformed into free-radical initiators for the in situ free-radical graft polymerization to prepare s-PS-g-PMMA graft copolymers. 

GBCH-polymers were the first synthetic materials that displayed relatively high thromboresistance. For instance, poly(methyl methacrylate) grafts, having been coated with GBCH and implanted in dog s vena cava, were patent for 14 days, while uncoated PMMA grafts were totally covered with thrombin within the first 2 hours44). 

EPDM-g-PMMA was produced through ATRP with CuBr/bipyridine [80]. The graft copolymer, which had an ethylene-propylene terpolymer (EPDM) backbone and PMMA branches, was prepared from brominated EPDM that was produced with NBS to introduce allylbromine moiety on the backbone. Resulting EPDM-g-PMMA graft copolymers were characterized by solvent extraction, infrared (IR), and NMR techniques. 

Figure 2. Effect of carbonyl group content on the yield of copolymer, molecular weight, and apparent number of grafted chains in the pMMA-grafted dialdehyde-cellulose. Conditions cellulose, 0.3 g H2(), 10 mL MMA, 2 mL at 50°C for 1 h. Key (reaction tube) O, quartz d.Pyrex.

Figure 5. Effect of organic solvent concentration on the yield of copolymer and molecular weight of grafted chains in the pMMA-grafted dialdehydecellulose using a quartz lube. Conditions cellulose (C — 0, 29.8 mmol/100 g), 0.3 g H,0 + solvent, 10 mL MMA, 2 mL 50°C. Key to solvent O, CC/(, 1.5 h X, (CHs)t-CHCH%OH, 1.25 h A, HCON(CHs)t, 1 h <>, (CHs)2CO, 3 h.

Figure 8. Effect of reaction temperature on the yield of copolymer in the pMMA-grafted dicarboxylcellulose using a Pyrex tube. Conditions cellulose, 0.3 g HsO, 10 mL. Key [cellulose COOH content (mmol/100 g)] O, 6.8 A, 18.1 0, 55.0. Key (reaction time) open mark, 1 h half closed mark, 1.4 h.

Viscosity. The viscosity measurements of the PMMA graft chains obtained by hydrolysis of graft copolymer were carried out in benzene at 30°C using an Ubbelhode viscometer, and the number average molecular weight of the grafted chain was calculated using the equation(25) ... 

This shows that at low monomer concentrations, most of the azoradicals formed are utilized in grafting reactions rather than initiating homopolymerization of MMA. The molecular weights of the isolated PMMA grafts were found to increase with increase in monomer concentration with both initiators. 

Yamashita et al.2,99) also investigated the copolymerization of PMMA macromonomers both with a mixture of HEMA and perfluoroalkyl acrylate and with a MMA-methacrylic acid mixture here again, the PMMA grafts originating from the macromonomer play the role of anchoring segments, and surface accumulation of the functional backbone segments is well established. 

A similar procedure was used with co-dicarboxy-PMMA macromonomers 105). They were mixed with another diacid (sebacic acid) and reacted stoichiometrically with a diamine (p,p -diaminodiphenylmethane and others) at 100 °C in N-methyl-pyrrolidone/pyridine mixtures. The formed polyamide was shown to contain PMMA grafts although the proportion of MMA was slightly lower than in the feed. 

Poly(HEMA-co-MMA-g-PMMA) graft copolymer was also prepared with a commercially available poly(methyl methacrylate) (PMMA) macromonomer, HEMA, and MMA, and used as an efficient dispersant for the dispersion polymerization of styrene in ethanol [152]. 

Simultaneously, the molecular weight of the particles is reduced from M 10 g mol to M 10 g mol [9]. Fig. 2a and 2b illustrate the monodispersity of precrosslinked poly(organo-siloxane) particles and of PMMA grafted core/shell particles, respectively. 

The diameters of the particles, prepared from dispersion, are approximately 120 nm each. The powder morphology of spray-dried PMMA grafted siloxane particles is illustrated in Fig. 3a the spherical agglomerates are approximately 1-20 pm in size. The microstructure of the graft copolymer after processing is shown in Fig. 3b. 

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