Chloromethyl oxetane BCMO

Farthing [55] made the earliest report of the polymerization of BCMO. The catalysts used were BF3 and BF3. EtjO. He did not study the kinetics and mechanism of this polymerization. 

A variety of aluminium alkyls either alone or in combination with additives has been used for the polymerization of BCMO [58]. The characteristics of most of these initiators are similar both in composition 

In 1969 Penczek and Kubisa [59] reported an exhaustive study of the kinetics and mechanism of BCMO polymerization initiated by the (i-C4H9 )j AI/H2O system and carried out in chlorobenzene solution at 55—95°C. This system produced homogeneous conditions for the polymerization and the whole process could be described as a non-stationary reaction with slow initiation, fast propagation, and slow degradative chain transfer to polymer. 

By applying these equations and carefully determining the stai ting concentration of active species, Penczek and Kubisa [59] obtain the following values of the absolute rate coefficients at 70°C = 1.6 x 10  

The catalytic activity of aluminium alkyl and of aluminium alkyl-water systems could be further enhanced by the addition of readily polymerizable oxides, usually epoxides such as ECH or PO, (promoters) [62]. These initiators are very active with BCMO but the primary kinetic studies 

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A similar technique was used almost simultaneously by Penczek [18, 19] for the polymerisation of bis-chloromethyl oxetan (BCMO) by (i-Bu)3A/-H20 in chlorobenzene. In this system, too, there is termination by reaction of growing centres with polymer, but initiation is slow and the equations are correspondingly more complicated. The authors believe that their value of the propagation rate-constant refers to ion-pairs and is thus k"v, and we see no reason to disagree with their view they also determined k and kt. 

The degree and type of substitution has much effect on the properties of the polymer, as well as the rate of polymerization. Increasing methyl substitution at position-3 gives a regular increase in the rate of polymerization, and the most useful properties are observed with polymers of 3,3-dialkyloxetanes, with melting points ranging from 50 to nearly 300 °C. The polymers of 3,3-bis(chloromethyl)oxetane ( BCMO ) have been commercial products for many years, known as Penton and Pentaplast (equation 31). 

The synthesis of AMO involves treatment of 3,3-bis(chloromethyl) oxetane (BCMO) with sodium azide in the DMF medium at 85 °C for 24 h. Similarly, AMMO which is a monofunctional analog of AMO is synthesized by the azidation of chloro/tosylate product of 3-hydroxymethyl-3-methyl oxetane (HyMMO) with sodium azide in DMF medium at elevated temperatures. These energetic monomers are readily polymerized to liquid curable prepolymers with the help of boron trifluoride etherate/l,4-butanediol initiator system and the outlines of synthesis [147-150] of poly(BAMO) [Structure... 

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... 

Cationic polymerization of 3,3-bis(chloromethyl)oxetane (BCMO) was in the past employed in the commercial process for making chlorinated polyether-Penton , polymer having very good chemical resistance toward aggressive media (e.g., cone. H2S04 up to 120° C). Relatively high price, due to the difficult monomer synthesis, was the reason, that Penton... 

The system is considerably simplified if some of the propagation steps may be treated as irreversible reactions [300,301], This is for example the case of cationic copolymerization of 3,3-bis(chloromethyl)oxetane (BCMO) and tetrahydrofuran (THF) studied experimentally [302,303],... 

BAMO polymer has two N3 bonds in every BAMO monomer unit. As shown in Table 4-10, the heat of formation of BAMO is positive, and the adiabatic flame temperature is higher than that of GAP. BAMO monomer is synthesized by replacing C-Cl bonds of 3,3-bis (chloromethyl) oxetane (BCMO) by C-N3 bonds1151. The mo-... 

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. 

The polymerization of 3,3-bis(chloromethyl)oxetane (BCMO) initiated with living polytetrahydrofuran (polyTHF) was studied by Saegusa 117). In this system, due to the high equilibrium concentration of THF, some monomer remains in equilibrium with the polymer after the first stage is completed (i.e. at the polyTHF THF equilibrium). After addition of the second monomer, the remaining THF may participate in copolymerization with added BCMO (cf. Sect. 15.2.2.1., copolymerization above T0), leading to random copolymer. Only after the complete consumption of THF the second monomer may form the required homoblock. Thus, the two homoblocks are separated by a third random BCMO/THF copolymer block ... 

Fig. 19. Synthesis of polyethers from 3,3-bis(chloromethyl)oxetane (BCMO) and various bi-sphenols. Reprinted from (1997) Eur Polym J (1997) 33 187 [85] with permission...

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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