Comonomers, cyclic reactive

Vinyl substituted cyclic hemlamidals 2 and their Interconvertible acetal precursors (eg. acrylamldo-butyraldehyde dimethyl acetal 1) were Incorporated as latent crosslinkers and substrate reactive functional comonomers In solution and emulsion copolymers. Some use and applications data for copolymers prepared with these new monomers are presented. They show low energy cure potential, long shelf life and high catalyzed pot stability In solvent and aqueous media, good substrate reactivity and adhesion, and good product water and solvent resistance. They lack volatile or extractable aldehyde (eg. formaldehyde) components and show enhanced reactivity and hydrolytic stability with amines and diol functional substrates. 

For copolymerizations proceeding by the activated monomer mechanism (e.g., cyclic ethers, lactams, /V-carboxy-a-amino acid anhydrides), the actual monomers are the activated monomers. The concentrations of the two activated monomers (e.g., the lactam anions in anionic lactam copolymerization) may be different from the comonomer feed. Calculations of monomer reactivity ratios using the feed composition will then be incorrect. 

THF copolymerizes readily with other cyclic ethers such as oxides and oxetanes. The comonomers used include ethylene oxide (67), propylene oxide (99,100), epichlorohydrin (ECH) (101,102), phenyl glycidyl ether (102), 3.3-bis(chloromethyl) oxetane (BCMO) (25, 98, 101, 103) and 3-methyl-3-chloromethyl oxetane (103). Just as in THF homo-polymerization, a large variety of catalysts have veen used. In many cases the kinetics of copolymerization have been studied. Table 22 summarizes the monomer reactivity ratios, rx (THF), and r2 (comonomer) which have... 

In the random copolymerization process, both types of active species should be able to participate in the cross-propagation reactions. This imposes certain limitations on the choice of comonomers in the cationic polymerization of heterocyclic monomers. Onium ions, being the active species of these polymerizations, differ considerably in reactivity thus, as already discussed, oxonium ions initiate the polymerization of cyclic amines, whereas ammonium ions do not initiate the polymerization of cyclic ethers and the corresponding cross-propagation reaction would not proceed ... 

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