Synthesis and polymerization of cyclobutenyl-functionalized polylactide and polycaprolactone: a consecutive ROP/ROMP route towards poly(1,4-butadiene)-g-polyesters

Abstract

International audienceEfficient preparation of cyclobutenyl end-functionalized polyester macromonomers bearing polylactide (PLA) or poly(ε-caprolactone) (PCL) arms was achieved by organocatalyzed ring-opening polymerization (ROP) of L-lactide or ε-caprolactone in the presence of cis-3,4-bis(hydroxymethyl)cyclobutene or cis-4-benzyloxymethyl-3-hydroxymethylcyclobutene acting as an initiator. Cyclobutenyl end-functionalized PLA and PCL macromonomers having one or two arms were obtained in high yields with excellent control over molecular weights (up to 11 000 g mol−1) and dispersity (PDI < 1.25) by organocatalyzed ROP using 4-(N,N-dimethylamino)pyridine (DMAP) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), respectively. Ring-opening metathesis polymerization (ROMP) of the macromonomers using ruthenium-based Grubbs' second generation catalyst afforded well-defined polybutadiene-g-polyester copolymers having an exclusively linear polybutadiene backbone with a strictly 1,4-type microstructure, with molecular weights ranging from 20 000 to 170 000 g mol−1 and low dispersities (PDI ≤ 1.30). The products resulting from this consecutive ROP/ROMP route represent the first examples of poly(1,4-butadiene)-g-polyesters through the macromonomer route

Design and characterization of antimicrobial usnic acid loaded-core/shell magnetic nanoparticles

“…A significant variation of the MNP surface charge was observed after polymer coating. Specifically, MNP coating by sbPCL 50 suppressed the effect of the OH resulting in an almost uncharged nanocomposite (+ 1 mV). On the contrary, the two MNP samples having a pAcDED shell showed positive (+ 20 mV) charge at neutral pH indicating a protonation of the polymer tertiary amino groups.…”

“…In this study, in order to develop drug targeting systems to be employed for the treatment of localized infections, these manganese iron oxide MNPs were coated with either a hydrophilic basic polyacrylamide (pAcDED) or a hydrophobic star-branched poly-ε-caprolactone (sbPCL 50 ). The rationale of the work was to provide MNPs with a proper polymer shell able not only to decrease MNP aggregation but also to produce an engineered surface possessing specific functional groups and binding sites for drug loading.…”

“…1) was confirmed by 1 H-NMR (300 MHz, d-DMSO): δ = 1.60-1.80 (m, -CH 2 CH 2 ), δ = 2.60 (m, -CH 2 CO), δ = 3.65 (t, -CH 2 OH), δ = 4.20 (m, -CH 2 OCO). 1 H-NMR analysis was also used to determine the number-average degree of polymerization of each arm of the polymer (DP n ), from the ratio of the integrated area between the peak at 3.65 related to the chain ends and the peak at 4.2 attributed to the methylene groups linked to the ester oxygen [50]. The number-average molecular weight (M n ) and polydispersity index (I) were measured by Gel Permeation Chromatography (GPC) using a 150-C Waters GPC apparatus equipped with a differential refractive index detector.…”

“…The state of aggregation of MnFe 2 O 4 was discretely reduced by the introduction of sbPCL 50 and pAcDED as coatings. Even if some aggregates are still present in both samples ( Fig.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…Other ring systems that have been subjected to ROMP reactions are depicted in Figure 4 and include: (1) cyclobutenes connected to poly(lactone) chains (e.g. 85) [377]; (2) cyclobutene derivatives (e.g. 84) and cyclohexene (copolymer) [378]; (3) cyclopentenes (e.g.…”