Cascade synthesis of chiral block copolymers combining lipase catalyzed ring opening polymerization and atom transfer radical polymerization

J.W. Peeters, A.R.A. Palmans, M.A.J. Veld, F.J.E. Scheijen, A. Heise, E.W. Meijer

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

97 Citaten (Scopus)

Samenvatting

The enantioselective polymerization of methyl-substituted -caprolactones using Novozym 435 as the catalyst was investigated. All substituted monomers could be polymerized except 6-methyl--caprolactone (6-MeCL), which failed to propagate after ring opening. Interestingly, an odd-even effect in the enantiopreference of differently substituted monomers was observed. The combination of 4-methyl--caprolactone with Novozym 435 showed good enantioselectivity also in bulk polymerization and resulted in enantiomerically enriched P((S)-4-MeCL) (eep up to 0.88). Subsequently, a novel initiator combining a primary alcohol to initiate the ring opening polymerization and a tertiary bromide to initiate atom transfer controlled radical polymerization (ATRP) was synthesized, and showed high initiator efficiencies (>90%) in the ring opening polymerization of 4-methyl--caprolactone in bulk. In addition, the enantioselectivity was retained (E = 11). By using Ni(PPh3)2Br2 as the ATRP catalyst, Novozym 435 could be effectively inhibited at the desired conversion of 4-methyl--caprolactone, thus ensuring a high enantiomeric excess in the polymer backbone. At the same time, Ni(PPh3)2Br2 catalyzed the ATRP of methyl methacrylate resulting in the formation of P((S)-4-MeCL-b-MMA) block copolymers. By this combination of two inherently different polymerization reactions, chiral P((S)-4-MeCL-b-MMA) block copolymers can be conveniently obtained in one pot without intermediate workup.
Originele taal-2Engels
Pagina's (van-tot)1862-1868
TijdschriftBiomacromolecules
Volume5
Nummer van het tijdschrift5
DOI's
StatusGepubliceerd - 2004

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