Epichlorohydrin, polymerization oxetane

The cationic ring-opening polymerization of epichlorohydrin in conjunction with a glycol or water as a modifier produced hydroxyl-terminated epichlorohydrin (HTE) liquid polymers (1-2). Hydroxyl-terminated polyethers of other alkylene oxides (3 4), oxetane and its derivatives (5 6), and copolymers of tetrahydrofuran (7-15) have also been reported. These hydroxyl-terminated polyethers are theoretically difunctional and used as reactive prepolymers. 

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... 

The scope of applications of cationic oxetane polymerization is rather limited, with one exception [3,3-bis(chloromethyl)oxetane, BCMO] polyoxetanes have not found any practical application. BCMO, is not as easily available as some of the 3-or 5-membered cyclic ethers (ethylene oxide, propylene oxide, epichlorohydrin, tetrahydrofuran) which are made from simple petrochemical products. 

Oxepanes are polymerized by various cationic initiators like (C2H5)3C BF4 , (C2H5)3C -SbCl6 , BF3-epichlorohydrin, and SbCl6-epichlorohydrin. The reactions take place in chlorinated solvents, like piethylene chloride. The rates of these reactions, however, are quite slow. In addition, these polymerizations are reversible. The rates of propagation of the three cyclic ethers, oxetane, tetrahydrofuran, and oxepane, at 0 °C fall in the following oider ... 

Monomers. Commercial, polymerization grade monomers were used as received. The sources were ethylene oxide (EO), propylene oxide (PO), and epichlorohydrin (ECH) from Union Carbide Corp. allyl glycidyl ether (AGE) from Shell Chemical Coip.j butadiene monoxide (BMO) from PPG Industries, Inc. (no longer commercially available) and 3,3-bis(chloromethyl) oxetane (BCMO) from Hercules Incorporated (no longer commercially available). 

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