Rapid and Controlled Organocatalyzed Ring-Opening Polymerization of 3S-(Isobutyl)morpholine-2,5-dione and Copolymerization with Lactide

Abstract

Morpholine-2,5-diones are increasingly attractive monomers derived from amino-acids whose copolymerization with other monomers produces interesting biodegradable materials. In this study, the rapid and controlled organocatalyzed ring-opening polymerization of 3S-(isobutyl)­morpholine-2,5-dione (MD) and its copolymerization with lactide (LA) was accomplished using 1,8-diazabicyclo­(5,4,0)­undec-7-ene and a thiourea (TU) cocatalyst. The amount of TU used for the polymerization was found to be fundamental for achieving good control. A range of polymers with molecular weights between 8.1 and 25.2 kg mol–1 was thus produced with narrow chain distributions (Đ = 1.13–1.18) in short periods (5 to 10 min). Secondly, copolymers with varying compositions (MD:LA = 25:75;50:50; 75:25) were prepared (11.2 to 12.7 kg mol–1; Đ = 1.09–1.26). The kinetics of these polymerizations suggest that concurrent thioimidate and cyclic imidate mechanisms are occurring and that these are governed by the quantity of TU in respect to MD.

Simple and Rapid Mechanochemical Synthesis of Lactide and 3S-(Isobutyl)morpholine-2,5-dione-Based Random Copolymers Using DBU and Thiourea

“…33−35 To date, besides those studies by Kim et al, the field of mechanochemical ROP (mechaROP) is unexplored and mechanochemical copolymerization (mechaROCP) has yet to be investigated. 24 clohexylthiourea (TU)), 36 we report herein on the mechaROP of 3S-(isobutyl)morpholine-2,5-dione (MD) and mechaROCP with LA. This permits a direct and pertinent comparison with our previous solvent-based study.…”

“…Although LAG slightly improved the kinetics, the low monomer conversion obtained was unexpected as the same catalytic system proved highly efficient when polymerizing MD in solution, achieving total monomer conversion in 5 min. 36 In addition to a low monomer conversion, the peaks in the 1 H NMR spectrum of the crude product obtained from PMD2 were remarkably broad, a characteristic that disappears when the sample was filtered through cotton (see Figure S1). This is a tell-tale sign that paramagnetic species are present within the sample.…”

Balancing Degradability and Physical Properties of Amorphous Poly(d,l‐lactide) by Making Blends

“…The ester functional groups in polymer backbone repeat units can be hydrolyzed under appropriate environments leading to the breakage of the polymer chain (fragmentation) followed by bio‐assimilation of fragmented oligomers and monomers to carbon dioxide (CO 2 ), water, and biomass. [ 4–9 ] This two‐step process is called biodegradation. The first step of biodegradation, the process of fragmentation to oligomers and monomers, is highly critical for the whole process of biodegradation as long macromolecule chains with high molar mass cannot be bio‐assimilated.…”

Cooligomers from morpholine-2,5-dione and para-dioxanone and catalyst complex SnOct2/2-hydroxyethyl sulfide

“…Another advantage of this catalyst is the possibility to cleave the disulfide group of the synthesized polymers with a reducing agent [2] such as dithiothreitol and thereby generating a bifunctional oligomer carrying a sulfide group on one side and a hydroxyl group on the other as demonstrated earlier [2]. We investigated this catalyst complex for the ROP of a morpholine-2,5-dione (MD) [3][4][5][6][7], PDX and their cooligomers. A series of homo-and cooligomers was synthesized by ROP of SBMD (1) and PDX (2) in one-pot reactions, in which the ratio of SBMD to PDX was varied.…”