Search results for "Lactide"
showing 7 items of 47 documents
One-pot synthesis of poly(l-lactide) multi-arm star copolymers based on a polyester polyol macroinitiator
2013
Abstract Using a hyperbranched poly(glycolide) ( hb PGA) macroinitiator the synthesis of poly( l -lactide) (PLLA) multi-arm star polyesters has been achieved via a core-first approach. The star-shaped copolymers were prepared in a one-pot two-step process via Sn(Oct) 2 -catalyzed ring-opening polymerization (ROP) conducted in the melt. Complete conversion of the end groups of the hb polyglycolide polyester polyols is ensured by the reactive primary hydroxyl termini. By adjusting the monomer/initiator ratio a series of star copolymers with varying PLLA arm length has been obtained with molecular weights in the range of 1500 to 10,000 g/mol (SEC). The successful coupling of the PLLA arms to t…
Characterization and Processability of Blends of Polylactide Acid with a New Biodegradable Medium-Chain-Length Polyhydroxyalkanoate
2015
In this work the processability and the mechanical performance of polylactide acid (PLA) based blends with a sample of a new biodegradable medium-chain-length poly (hydroxyalkanoate) (PHA) were investigated. The two polymers are incompatible with scarce adhesion and with the dispersed PHA particles size increasing with the PHA content. Rheological tests in shear flow indicate that adding PHA improves the processability of the matrix by increasing the content of this second component in the blend, as observed also for the torque curves, due to the very low viscosity of this new sample of PHA. The processability is only slightly worsened in non-isothermal elongational flow as the melt strengt…
Preparation and Recycling of Plasticized PLA
2010
Poly(lacticacid)(PLA)hasbeengainingarisinginterestoverthe last years as a biodegradable and environmental-friendly substitute of traditional non-biodegradable poly-mers.Several ways exist to synthesize PLA, however, poly-merization through lactide formation is the most used onindustrial scale, allowing to obtain optimum results interms of mechanical and thermal properties.
Facile and efficient chemical functionalization of aliphatic polyesters by cross metathesis
2016
International audience; An effective preparation of new tailor-made macromolecular materials via a combination of two (atom-efficient) catalytic transformations is reported. First, new aliphatic polyesters with alternated composition have been prepared using a salen aluminum catalyst system. Next, the pendant vinyl moieties in those copolymers have been selectively transformed into various functional groups by metathesis in the presence of homogeneous Grubbs catalysts. The latter metathesis reaction has been optimized in terms of catalytic activity and selectivity, to define the conditions for an effective and safe procedure that does not affect the macromolecular architecture. All polymer …
Compatibilization of Polylactide/Poly(ethylene 2,5-furanoate) (PLA/PEF) Blends for Sustainable and Bioderived Packaging.
2022
Despite the advantages of polylactide (PLA), its inadequate UV-shielding and gas-barrier properties undermine its wide application as a flexible packaging film for perishable items. These issues are addressed in this work by investigating the properties of melt-mixed, fully bioderived blends of polylactide (PLA) and poly(ethylene furanoate) (PEF), as a function of the PEF weight fraction (1–30 wt %) and the amount of the commercial compatibilizer/chain extender Joncryl ADR 4468 (J, 0.25–1 phr). J mitigates the immiscibility of the two polymer phases by decreasing and homogenizing the PEF domain size; for the blend containing 10 wt % of PEF, the PEF domain size drops from 0.67 &p…
Comparative Investigation on the Soil Burial Degradation Behaviour of Polymer Films for Agriculture before and after Photo-Oxidation
2020
Polymer films based on biodegradable polymers, polyethylene (PE) and modified PE with oxo-degradable additive were prepared by film blowing. Carbon black (1%) was added to all the films. Commercial biodegradable Ecovio®
In Vitro Evaluation of Poly(lactide-co-glycolide) In Situ Forming Gels for Bedaquiline Fumarate Salt and Pharmacokinetics Following Subcutaneous Inje…
2021
This study evaluated in vitro and in vivo drug release of bedaquiline from in situ forming gels (ISGs) containing 200 mg eq./g bedaquiline fumarate salt prepared with four different grades of poly(d,l-lactide) (PDLLA) or poly(d,l-lactide-co-glycolide) (PLGA) with a lactide/glycolide ratio of 50/50 or 75/25 and acid (A) or ester (E) end-capping in N-methyl-2-pyrrolidone at a polymer/solvent ratio of 20/80% (w/w). Mean in vitro drug release in 0.05 M phosphate buffer pH 7.4 with 1% (w/v) sodium lauryl sulphate was 37.3, 47.1, 53.3, and 62.3% within 28 days for ISGs containing PLGA5050A, PDLLA, PLGA7525A, and PLGA7525E, respectively. The data suggested that drug release was primarily controlle…