Analysis of the essential oils of Salvia Libanotica and Origanum Syriacum

ABSTRACT Essential oils (EO's) of Salvia libanotica and Origanum syriacum grown in Lebanon were extracted by two different techniques; hydrodistillation and cold solvents extraction using different solvents systems according to their polarity. The essential oil was analyzed using GC/MS. The results identified 35 constituents in each of Salvia Libanotica and Origanum syriacum extracts

Synthesis, characterization, and enhanced electrochemical behavior of polypyrrole doped ZrO2–ZnO electrode materials for supercapacitor applications

The polypyrrole@ZrO2–ZnO (PPy@ZrO2–ZnO) electrodes were synthesized using an in situ chemical oxidative method. The samples were characterized by XRD, FTIR, XPS, UV-vis, TGA, and BET. In addition, the electrochemical characteristics of the electrodes are tested by cyclic voltammetry (CV), galvanostatic charge and discharge (G.C.D.), and electrochemical impedance spectroscopy (E.I.S.). The values of the specific capacitances and the energy densities of PPy@ZrO2–ZnO (1.0) and PPy@ZrO2–ZnO (0.5) at a current density of 0.5 A g−1 are recorded as (395.3 F g−1 and 508.5 Wh·kg−1) and (195.3 F g−1 and 351.5 Wh·kg−1), respectively. Furthermore, the electrode stability for the formed samples was also determined, which exhibited specific capacitance retention at 90.2% for PPy@ZrO2–ZnO (1.0) and 82.4% for PPy@ZrO2–ZnO (0.5) after cycling up to 4,000 cycles. This work provides an efficient approach to the potential of the synthesized samples for application as electrodes in a supercapacitor

Étude par RMN des complexes d'inclusion avec des cyclodextrines natives et polymérisées

La structure des différentes cyclodextrines natives et polymérisées a été étudiée par RMN. Puis la capacité d'indusion de ces différentes cyclodextrines avec des molécules organiques comme la doxycycline, la jasmone et le citronellol a été testée. La stoechiométrie de ces différents complexes a eté déterminée avec la méthode de Job. Les mesures de constante d'association permettant d'estimer la stabilité du complexe ont été réalisées à partir de deux paramètres différents: déplacement chimique (méthode de Scott) et coefficient de diffusion (DOSY). L'inclusion des molécules organiques dans la cavité des cyclodextrines natives et polymérisées a été prouvée à partir de l'expérience RMN ROESY 2D. Enfin, les polymères de cyclodextrines insolubles et les textiles greffés avec des cyclodextrines ont été étudiés par HR-MAS.LILLE1-BU (590092102) / SudocSudocFranceF

Diffusion ordered spectroscopy (DOSY) as a powerful tool for amphiphilic block copolymer characterization and for critical micelle concentration (CMC) determination

International audienceDiffusion-ordered spectroscopy (DOSY)NMRwas successfully used to characterize amphiphilic block copolymers. A triblock copolymer was prepared by ring-opening polymerisation of a lactide using poly(ethylene glycol) as the initiator. The DOSY NMR experiment is revealed to be a useful analytical method to prove the formation of block copolymers. According to the DOSY map, PLA and PEG blocks exhibited the same diffusion coefficient of 5.623 10 10 m2 s 1, consistent with an efficient polymerisation of the lactide. The determination of the critical micelle concentration (CMC) using DOSY NMR experiments has also been reported. The CMC value correlated with those obtained by fluorimetry and static light scattering. The CMC value was found to be 0.11 g L 1. All the results suggest that DOSY NMR is a valuable analytical tool for the polymer community. The good correlation between the results from DOSY, fluorescence and SLS experiments suggests that the DOSY spectroscopy can accurately measure the CMC of amphiphilic copolymer solutions

Redox and thiol–ene cross-linking of mercapto poly(ε-caprolactone) for the preparation of reversible degradable elastomeric materials.

International audienceA novel thiol-functionalized PCL (PCL-HDT) was synthesized following a convenient two-step procedure. Taking advantage of the pendant thiol group, degradable elastomeric materials have been prepared from PCL-HDT by redox or thiol–ene reaction. Elastomers were characterized by HRMAS NMR spectroscopy to confirm the formation of disulfide or thioether cross-links. The thermal and mechanical properties of elastomers have been assessed by DSC, DMA and tensile tests. Disulfide containing elastomers (EMSS) and thioether containing elastomers (EMTE) exhibited improved mechanical properties with ultimate strains up to 220%. The stability of the mechanical properties at temperatures close to body temperature was confirmed by DMA with G′ ≈ 200 MPa and G′′ ≈ 15 MPa. Finally, the reversibility of the disulfide formation and breaking has been evaluated, and confirmed the potential of these degradable elastomers as biomaterials

Brush-like amphiphilic copolymers based on polylactide and poly(ethylene glycol): Synthesis, self-assembly and evaluation as drug carrier

International audienceA series of novel amphiphilic poly(poly(ethylene glycol) methacrylate)-block-poly(l-lactide)-block-poly(poly(ethylene glycol) methacrylate) (P(PEGMA)-b-PLLA-b-P(PEGMA)) copolymers were synthesized by combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). First, two α,ω-telechelic PLLA ATRP macroinitiators were prepared in two steps via ROP of l-lactide using a difunctional initiator, and subsequent reaction of the hydroxyl end groups with 2-bromoisobutyryl bromide. Then, the ATRP of poly(ethylene glycol) methacrylate was carried out using PLLA macroinitiators. The resulting brush-like triblock copolymers were characterized by 1H NMR, size exclusion chromatography and DOSY NMR. The aggregation behavior of the copolymers in aqueous medium was investigated by fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The critical aggregation concentration was in the range of 0.08-0.12 g L−1. The diameter of the nanoparticles (NPs), determined by DLS, was around 100 nm. TEM images showed that these nano-sized objects were spherical in shape. Preliminary studies with a hydrophobic model drug, namely clofazimine, exhibited that such NPs could be potential candidates for drug delivery carrier

From nanospheres to micelles: simple control of PCL-g-PEG copolymers amphiphilicity through thiol–yne photografting

International audienceA simple method for the synthesis of a family of poly(ε-caprolactone)-g-polyethylene glycol (PCL-g-PEG)copolymers of controlled amphiphilicity and their use in generating nanospheres or micelles are reported.PCL-g-PEGs with various compositions are prepared from a single strategy relying on a combination ofpost-polymerization modification and subsequent thiol–yne photografting. Alkyne-functional PCL (PCLyne)was first obtained by anionic activation and reaction with propargyl bromide to yield PCL-yne with8% alkyne groups. PEG-thiol is then reacted on PCL-yne under UV activation to yield the targeted graftcopolymer by thiol–yne photoaddition. The advantage of the approach is that control over the compositionis easily achieved, yielding amphiphilic graft copolymers with ethylene glycol/caprolactone (EG/CL)ratios ranging from 0.1 to 1.3. Starting from this single strategy, it was therefore possible to obtain nanospheres(DH ∼ 55 nm) or micelles (DH ∼ 30 nm) by copolymer self-assembly depending on the EG/CLratio. The potential of PCL-g-PEG micelles as drug carriers was finally evaluated with curcumin thatwas efficiently encapsulated, protected and released over 80 days. Interestingly it was found that drugencapsulation efficiency and drug loading were higher for PCL-g-PEG copolymers compared to blockPCL-b-PEG

Double-Hydrophilic Block Copolymers Based on Functional Poly(ε-caprolactone)s for pH-Dependent Controlled Drug Delivery

International audienc

Sensitized [2 + 2] intramolecular photocycloaddition of unsaturated enones using UV LEDs in a continuous flow reactor: kinetic and preparative aspects

International audienc

Degradable double hydrophilic block copolymers and tripartite polyionic complex micelles thereof for small interfering ribonucleic acids (siRNA) delivery

International audienc