Ring-opening polymerization of caprolactone

The preparation of poly( -caprolactone) given below is a bulk ring-opening polymerization of -caprolactone initiated by Ti(OBu)4 in the presence of... 

Five-coordinate aluminum alkyls are useful as oxirane-polymerization catalysts. Controlled polymerization of lactones102 and lactides103 has been achieved with Schiff base aluminum alkyl complexes. Ketiminate-based five-coordinate aluminum alkyl (OCMeCHCMeNAr)AlEt2 were found to be active catalyst for the ring-opening polymerization of -caprolactone.88 Salen aluminum alkyls have also been found to be active catalysts for the preparation of ethylene carbonate from sc C02 and ethylene oxide.1 4 Their catalytic activity is markedly enhanced in the presence of a Lewis base or a quaternary salt. 

Another approach is to use an initiator for ATRP that produces a polymer with a functional group capable of initiating a non-ATRP polymerization. ATRP polymerization of methyl methacrylate with 2,2,2-tribromoethanol produces an HO-terminated poly(methyl methacrylate). The hydroxyl group acts as an initiator in the presence of triethyl aluminum for the ring-opening polymerization of caprolactone. 

The heterobimetallic complexes Li[Ln(7]S 7]1-CsR4SiMe2NCH2CH2X)2] catalyze the ring-opening polymerization of -caprolactone (Scheme 264). The product of this polymerization had a high molecular weight Mn > 30 000 Da and moderate polydispersity (Mw/Mn < 2.0). The polymerization was carried out in toluene or dichloromethane at room... 

The cationic ring opening polymerization of -caprolactone, CL, and 5-valerolactone, VL, was investigated using n-BuOH/HCl Et2O as the initiation system [56]. It was observed that narrow molecular weight distribution samples were obtained. These results were combined with those previously... 

Fig. 15.2 Schematic representation for covalent attachment of hydroxyl groups to MWCNTs by free radical addition of 4,4 -azobis(4-cyanopentanol) in water and subsequent surface-initiated ring-opening polymerization of -caprolactone in room-temperature ionic liquids (BmimBF )...

Figure 12.2 Enantioselective enzyme-catalyzed ring-opening polymerization of caprolactone from PHB-diol [10].

Okuda, J., Rushkin, I. L. Mono(cyclopentadienyl)titanium complexes as initiators for the living ring-opening polymerization of -caprolactone. Macromolecules. 1993,26, 5530-5532. 

It was also shown that functional zinc alkoxides are also effective initiators for the ring-opening polymerization of -caprolactone imder very mild conditions via a polymerization mechanism described for aluminum alkoxides (345). Tin octoate, Sn(0(0)CCH(C2H5)C4H9)2, is another type of initiator to synthesize telechelics based on PCL. In particular, when it is used in conjunction with hydroxyl functional compounds or prepolymers, telechelics, linear and star-shaped block copolymers, or networks can be obtained via corresponding alkyl octoate formation (346-354). More recently, novel end-chain and mid-chain telechelics functionalized with photoactive groups of PCL were synthesized (355). 

Aliphatic Polycaprolactone (PCD Ring-opening polymerization of caprolactone... 

The ring opening polymerization of -caprolactone at high temperatures follows a pattern which is radically different from the one observed in solution under mild low temperature conditions. It is postulated that the phenomenon is best explained by assuming that several secondary processes occur simultaneously with the primary initiation and polymerization reactions. 

II. Kubies, D., Pantoustier, N., Dubois, Ph., Rulmont, A., Jerome, R., 2002, Controlled Ring-Opening Polymerization of -caprolactone in the presence of layered silicates and formation of nanocomposites. Macromolecules 35 3318-3320. 

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