Lactone copolymers

Sato [3] and Koyama [4] prepared lactone copolymers, (V) and (VI), respectively, that were effective in positive resist compositions suitable for use in super-microlithography processes such as the manufacture of super-LSI and high-capacity microchips. 

Malin, M., HUjanen-Vainio, M., Karjalainen, T. and Seppala, J. (1996) Biodegradable lactone copolymers. II. Hydrolytic study of E-caprolactone and lactide copolymers. Journal of Applied Polymer Science, 59, 1289-1298. 

The 15N is a unique series of TPU grades based on polyether-polycapro-lactone copolymers offering excellent hydrolysis resistance in combination with good heat resistance and mechanical properties. Additionally, the 15N Series excels for its outstanding low temperature performance and elastic properties. 

Poly( vinyl acetate-co-maleic anhydride) Fractional precipitation Acetone/petroleum ether Butyl ester lactonized copolymer 2268... 

As early as 1940 it has been established9 that diketene does not polymerize by a radical mechanism. It has, however, been shown later10 that it undergoes reactions of radical copolymerization with many vinyl monomers11. In this reaction the double bond is involved and the lactone ring is preserved in the copolymer. 

The effect of a catalyst is important in cationic copolymerizations. Epoxides and /3-lactones form random copolymers only with trialkyl aluminum catalysts. Unusual sequence distributions were observed in the cationic copolymerization of epoxides or lactones using Lewis acids175-177) have been attributed to the di-... 

A porphinatoaluminum alkoxide is reported to be a superior initiator of c-caprolactone polymerization (44,45). A living polymer with a narrow molecular weight distribution (M /Mjj = 1.08) is ob-tmned under conditions of high conversion, in part because steric hindrance at the catalyst site reduces intra- and intermolecular transesterification. Treatment with alcohols does not quench the catalytic activity although methanol serves as a coinitiator in the presence of the aluminum species. The immortal nature of the system has been demonstrated by preparation of an AB block copolymer with ethylene oxide. The order of reactivity is e-lactone > p-lactone. 

Stannous octoate has the advantage of having been used to prepare polymers (Silastic, Capronor) for which substantial toxicological data are now available (6,48). Stannous octoate-initiated polymerization has been used to prepare copolymers of e-caprolactone with other lactones, including diglycolide, dilactide, 6-valerolactone, e-decalactone, and other alkyl-substituted e-caprolactones. Conducting... 

The enantioselectivity was greatly improved by the copolymerization with 7- or 13-membered non-substituted lactone using lipase CA catalyst (Scheme 8) the ee value reached ca. 70% in the copolymerization of (3-BL with DDL. ft is to be noted that in the case of lipase CA catalyst, the (5 )-isomer was preferentially reacted to give the (5 )-enriched optically active copolymer. The lipase CA-catalyzed copolymerization of 8-caprolactone (6-membered) with DDL enan-tioselectively proceeded, yielding the (/ )-enriched optically active polyester with ee of 76%. 

The copolymerization of lactones took place through enzyme catalysis [92]. The copolymerization of e-CL with d-VL catalyzed by lipase PF affords the corresponding copolymer having a molecular weight of several thousand. From 13C NMR analysis, the copolymer was found to be of random structure having both units, suggesting the frequent occurrence of transesterifications between the polyesters. In the copolymerization of 8-OL with e-CL or DDL, random copolyesters were also formed [84], whereas the copolymer from e-CL and PDL was not statistically random [88]. 

The enzymatic polymerization of lactones could be initiated at the hydroxy group of the polymer, which expanded to enzymatic synthesis of graft copolymers. The polymerization of c-CL using thermophilic lipase as catalyst in the presence of hydroxyethyl cellulose (HEC) film produced HEC-gra/f-poly( -CL) with degree of substitution from 0.10 to 0.32 [102]. 

As described in Section 9.1.2.2.3, several lanthanocene alkyls are known to be ethylene polymerization catalysts.221,226-229 Both (188) and (190) have been reported to catalyze the block copolymerization of ethylene with MMA (as well as with other polar monomers including MA, EA and lactones).229 The reaction is only successful if the olefin is polymerized first reversing the order of monomer addition, i.e., polymerizing MMA first, then adding ethylene only affords PMMA homopolymer. In order to keep the PE block soluble the Mn of the prepolymer is restricted to <12,000. Several other lanthanide complexes have also been reported to catalyze the preparation of PE-b-PMMA,474 76 as well as the copolymer of MMA with higher olefins such as 1-hexene.477... 

The (TPP)A1X family of initiators has been used to initiate the polymerization of a range of other monomer classes including epoxides, episulfides, and methacrylates.776 In the latter case the propagating species is an aluminum enolate and this too may initiate the ROP of lactones, such as 6-VL, albeit slowly. In this way a block copolymer P(6-VL)-b-PM M A of narrow molecular weight distribution (Mw/Mn= 1.11) has been prepared.787... 

A series of bis(phenoxide) aluminum alkoxides have also been reported as lactone ROP initiators. Complexes (264)-(266) all initiate the well-controlled ROP of CL, NVL.806,807 and L-LA.808 Block copolymers have been prepared by sequential monomer addition, and resumption experiments (addition of a second aliquot of monomer to a living chain) support a living mechanism. The polymerizations are characterized by narrow polydispersities (1.20) and molecular weights close to calculated values. However, other researchers using closely related (267) have reported Mw/Mn values of 1.50 and proposed that an equilibrium between dimeric and monomeric initiator molecules was responsible for an efficiency of 0.36.809 In addition, the polymerization of LA using (268) only achieved a conversion of 15% after 5 days at 80 °C (Mn = 21,070, Mn calc 2,010, Mw/Mn = 1.46).810... 

The use of these initiators to polymerize LA814 and methylglycolide815 has been reported to proceed in a well-controlled fashion. Block copolymers such as PCL-b-PLA have also been prepared. Elimination of PrOH from the reaction of (270) with preformed hydroxyl terminated polymers, followed by lactone polymerization, yields diblocks of CL with polystyrene or polybutadiene.816 The preparation of an ABA triblock has also been reported (A = CL, B = LA) since propagating chains of PLA do not initiate CL ring opening, (270) was pretreated with hydroxy terminated (PCL-b-PLA)-OH 814... 

The lanthanocene systems have been extended to cover a range of monomers including LA,890 cyclic carbonates891 and even MMA.454 Block copolymers of MMA and lactones, with Mw/Mn = 1.11-1.23, may be prepared but only if the vinyl monomer is polymerized first. The... 

A 1992 patent describes the carbonylation of EO to yield /3-propiolactone using a mixture of Co2(CO)8 and 3-hydroxypyridine.982 A recent re-investigation of this system has indicated that the major product is the alternating copolymer, a polyester, catalyzed by the [Co(CO)4] anion (Scheme 24).983 The synthesis of lactones via this methodology has successfully been achieved using Lewis acidic counter-cations (Scheme 25) 984,985 a similar strategy allows /3-lactams to be... 

Anionic block copolymerizations of MM A with lactones proceeded smoothly to give copolymers with Mw/Mn = 1.11-1.23 when the monomers were added in this order. However, when the order of addition was reversed, no copolymerization took place [3c], i.e., no addition of MMA to the polylactone active end group occurred (Scheme 12). 

Yasuda et al. [122] extended the above work to the block copolymerization of ethylene with lactones. 5-Valerolactone and s-caprolactone were combined with the growing polyethylene end at ambient temperature and the expected AB-type copolymers (100 1 to 100 89) were obtained at high yield. Reversed addition of the monomers (first MMA or lactones and then ethylene) induced no block copolymerization at all, even in the presence of excess ethylene, and only homo-poly(MMA) and homo-poly(lactone) were produced. 

Conversions of about 80% were obtained within a few minutes at 90°C. The polymer could also be cleaved by cross-metathesis with an excess of 4-octene which gave, as the main product, 9-tridecenyl-7-undecenoate, thus confirming the structure assignment as indicated in Eq. (62). The unsaturated lactone was also copolymerized with cyclooctene, 1,5-cy-clooctadiene, and cyclopentene under the previously stated conditions to afford linear copolymers which were high molecular weight, unsaturated, rubbery polyesters (110). 

The purpose of this review is to report on the recent developments in the macromolecular engineering of aliphatic polyesters. First, the possibilities offered by the living (co)polymerization of (di)lactones will be reviewed. The second part is devoted to the synthesis of block and graft copolymers, combining the living coordination ROP of (di)lactones with other living/controlled polymerization mechanisms of other cyclic and unsaturated comonomers. Finally, several examples of novel types of materials prepared by this macromolecular engineering will be presented. 

Interestingly, the lactones copolymerization is responsible for a decrease in both and degree of crystallinity of the copolyesters when compared to the parent homopolymers. This behavior is illustrated in Fig. 1 in the case of po-ly( CL-co-6VL) random copolymers [35]. 

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