Poly(hydroxyalkanoate) Block or Random Copolymers of β-Butyrolactone and Benzyl β-Malolactone: A Matter of Catalytic Tuning. - Université de Rennes Accéder directement au contenu
Article Dans Une Revue Macromolecules Année : 2013

Poly(hydroxyalkanoate) Block or Random Copolymers of β-Butyrolactone and Benzyl β-Malolactone: A Matter of Catalytic Tuning.

Résumé

The controlled copolymn. of racemic β-butyrolactone (BL) and racemic benzyl β-malolactonate (MLABe) has been achieved under mild operating conditions (in bulk at 60 °C) with various systems derived either from a metal-based (pre)-catalyst assocd. with isopropanol (iPrOH) acting as a co-initiator and a chain transfer agent or more simply from a neat basic organocatalyst. Among the metallic systems evaluated, only the neodymium triflate-based catalyst system, Nd-(OTf)3/iPrOH, enabled the prepn., upon simultaneous addn. of the two monomers, of poly-(benzyl β-malolactonate-ran-β-butyrolactone) random copolymers (P-(MLABe-ran-BL)) with Mn,NMR up to 5800 g mol-1 (DM = ca. 1.4) as evidenced by 1H and 13C NMR. Simultaneous copolymn. of the comonomers mediated by the zinc β-diketiminate [(BDI)-Zn-\N-(SiMe3)2\]/iPrOH system only afforded PMLABe, leaving BL unreacted. Also, the sequential copolymn. with this zinc catalyst proceeded effectively only when BL was introduced prior to MLABe. In contrast, both the Nd-based system and basic organocatalysts of the guanidine (1,5,7-triazabicyclo[4.4.0]-dec-5-ene, TBD), amidine (1,8-diazabicyclo[5.4.0]-undec-7-ene, DBU), and phosphazene (2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine, BEMP) type effectively copolymd. MLABe and BL in a sequential approach, regardless of the order of comonomers addn., forming the corresponding P-(MLABe-b-BL) block copolymers, with segments of significant length (ca. 88 BL and 360 MLABe units; Mn,NMR up to 73 500 g mol-1 with DM = 1.44). Remarkably, BEMP afforded P-(MLABe-b-BL) from either a simultaneous or a sequential approach and regardless of the order of the comonomers addn. Kinetic and microstructural control in copolymn. of MLABe and BL can thus be achieved via catalytic tuning. [on SciFinder(R)]

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hal-01069947 , version 1 (30-09-2014)

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Citer

Cedric G. Jaffredo, Jean-Francois Carpentier, Sophie M. Guillaume. Poly(hydroxyalkanoate) Block or Random Copolymers of β-Butyrolactone and Benzyl β-Malolactone: A Matter of Catalytic Tuning.. Macromolecules, 2013, 46, pp.6765--6776. ⟨10.1021/ma401332k⟩. ⟨hal-01069947⟩
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