Methyl acrylate-vinyl chloride alternating

Methyl acrylate-vinyl chloride alternating copolymer... 

Block Copolymers. Several methods such as ultrasonics (100), radiation (101), and chemical techniques (102,103), including the use of polymer ions, polymer radicals, and organometallic initiators, are available to prepare Block Copolymers of acrylonitrile. Acrylonitrile can be used as either the first-or the second-phase monomer. Depending on the mechanism of termination, a diblock of the AB type and a triblock of the ABA type can be formed by disproportionation or transfer for the former, and recombination for the latter. Some of the comonomers are styrene, methyl acrylate, vinyl chloride, methyl methacrylate, vinyl acetate, acrylic acid, and re-butyl isocyanate. An overview and survey of alternating and block copolymers can be found in Reference 104. 

In Figure 15.18, plots of glass transition temperature vs. copolymer composition are given for (a) vinyl chloride/methyl acrylate (VC/MA) and (b) vinylidene chloride/methyl acrylate (VDC/MA). The behavior of copolymers with random and regularly alternating structures is compared. 

Subsequently emulsion polymerizations and copolymerizations involving polar monomers sudi as vinyl chloride (see Chapter 17), vinylidene chloride, vinyl acetate (see Chapter 16), methyl methacrylate, and butyl acrylate (see Chapter 18) proved to be of industrial interest The di rter, Polymerization in emulsion by Leverne Williams [10] includes an extorsive tabulation of the patent literature on polymerizations and copolymerizations in emulsion published up to 1955 and also comparisons of the effects of alternative emulsifiers in the saune polymerizations. 

Despite the universal adoption of PVC, some investigations have centred on the prospect of alternative matrix materials. Except for poly(vinylisobutyl ether) (71), poly(methyl methyl acrylate) (72), poly(methyl acrylate) (39) and poly(vinyl chloride/alcohol) copolymer (73), practically no functional calcium ISEs were realized with poly(vinylidene chloride) (19), cellulose acetate, ethyl cellulose, collodion or pyroxylin (11). Photocured sensor membranes based on acrylates are considered in section 3.4.4. 

Several procedures required for the preparation of porphyrins with labile side chains have already been referred to above or in the earlier article, for example, the conversion of acetoxyethyl or aminoethyl groups (introduced at the pyrrole stage) into vinyl groups. The preparation of porphyrin 3-keto esters has now been improved by the use of imidazolides (rather than acid chlorides) in condensations with magnesium methyl hydrogen malonate. The porphyrin acyl imidazolides have also been converted into acrylic esters by the sequence porCo-imidazole - -CH2OH — CHO - CH = CHC02Me. Alternatively the porphyrin ketoesters may be reduced with borohydride to hydroxyesters and dehydrated to acrylic esters. ... 

While most copolymers of vinyl acetate are random copolymers, alternating copolymers are formed when the reactivity ratios for the two monomers are suitable. This occurs spontaneously when vinyl acetate is polymerized with electron-poor monomers such as maleic anhydride [273]. Alternatively, it has been reported that acrylonitrile which has been precomplexed with zinc chloride gives alternating polymers with vinyl acetate [274]. Block polymers of vinyl acetate with methyl methacrylate, acrylonitrile, acrylic acid, and n-vinyl pyrrolidone have been prepared by the strategy of preparing poly(vinyl acetate) macroradicals in poor solvents in which the macroradicals are occluded. Addition of a second monomer swells the polymer coils, and polymerization continues with the addition of the new monomer [275]. 

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